The approach extends targeted protein degradation beyond the intracellular proteins commonly directed to the ubiquitin–proteasome system by PROTACs and molecular glues. The proteasome acts principally in the cytosol and nucleus, making it poorly suited to many secreted factors, extracellular proteins and membrane receptors, including cytokines, growth factors, immune checkpoints, receptor tyrosine kinases, adhesion receptors and transporters. Neutralizing or inhibiting these proteins can leave catalytic, scaffolding, ligand-independent or recycling-dependent functions intact, whereas eliminating them may provide a distinct pharmacological profile. Lysosome-targeting degraders, including LYTAC-like chimaeras, exploit cellular entry pathways naturally connected to extracellular and membrane cargo.

Early LYTAC designs linked a target-binding antibody to mannose-6-phosphate ligands that recruit the cation-independent mannose-6-phosphate receptor, CI-M6PR, also known as IGF2R. Later systems used the hepatocyte-enriched asialoglycoprotein receptor, ASGPR, often with triantennary N-acetylgalactosamine ligands, to direct uptake toward the liver. These approaches established the central principle of induced proximity: a bifunctional molecule can connect an extracellular or cell-surface target to an endogenous receptor and thereby bring it into the endolysosomal system. The field has since expanded to bispecific biologics, antibody fragments, ligand- and cytokine-guided chimaeras, compact synthetic degraders, aptamers, nucleic-acid scaffolds, polymers, nanoparticles, vesicles and genetically encoded systems.

Internalization, however, does not prove degradation. Once a target–degrader complex enters an endosome, it may be recycled to the plasma membrane, transported retrogradely, moved across a cell by transcytosis, retained in a non-degradative compartment or delivered to a lysosome. The review therefore treats receptor identity, binding kinetics, valency, geometry, linker length and rigidity, and complex lifetime as tools for controlling post-endocytic fate. Multivalent engagement can enhance avidity and, in suitable systems, promote receptor clustering, while pH-responsive interactions may release a recruited receptor in an acidifying endosome without releasing the target. Receptors already inclined toward lysosomal delivery may offer an advantage over handles chosen solely for rapid uptake.

Membrane proteins face an additional hurdle. After internalization, a transmembrane protein generally remains within the limiting membrane of an endosome and must enter intraluminal vesicles of multivesicular bodies before the full-length protein can be efficiently destroyed. Sorting of this kind can depend on receptor clustering, ubiquitination, membrane context, adaptor recruitment and the ESCRT machinery. For receptors such as EGFR, immune checkpoints, adhesion proteins and transporters, the design question is therefore not simply whether target and receptor can be internalized together, but whether the complex is committed to a degradative vesicular pathway. Recycling, retrograde transport, transcytosis and non-degradative endosomal retention are distinct failure modes rather than interchangeable evidence of activity.

The review proposes a five-tier evidence framework to distinguish binding and uptake from genuine destruction. Tier 1 covers target engagement and cellular uptake, establishing only that capture and delivery are feasible. Tier 2 requires reproducible, dose- and time-dependent reduction in total target protein, supported by orthogonal assays and controls for viability, assay interference and major changes in expression. Tier 3 is the decisive step: the reduction in total target must be reversed or substantially attenuated by an appropriate perturbation of lysosomal acidification or proteolysis. Tier 4 adds mechanistic evidence involving receptor dependence, trafficking, recycling, receptor fate and, for membrane proteins, multivesicular-body sorting, ubiquitination or ESCRT involvement. Tier 5 concerns translation, requiring target reduction in relevant tissues or cell populations alongside exposure, pharmacokinetic–pharmacodynamic relationships, selectivity and tolerability. The tiers assess a particular target, construct and biological context rather than assigning an intrinsic maturity level to an entire platform.

Surface flow cytometry, fluorescence uptake, microscopy and reduced surface staining can support target engagement or altered accessibility, but they cannot independently establish degradation. Apparent signal loss may result from epitope masking, target shedding, redistribution, conformational change, assay interference or receptor clustering. Quantitative immunoblotting, proteomics, targeted mass spectrometry, non-competing immunoassays, permeabilized flow cytometry and other orthogonal methods can help establish loss of the full target. Lysosomal inhibitors such as bafilomycin A1, concanamycin A, chloroquine, hydroxychloroquine and lysosomal protease inhibitors can test dependence, but they also affect endosomal trafficking, secretion, autophagic flux, signaling and cell fitness. Their use therefore requires viability controls and, where appropriate, target RNA measurements and complementary protein assays. Dose-response, time-course, washout and recovery experiments further distinguish durable depletion followed by resynthesis from redistribution or persistent assay interference.

Receptor selection creates opportunities but also imposes distinct liabilities. Broadly expressed CI-M6PR can provide access to lysosomal trafficking machinery, whereas ASGPR offers a liver-biased clearance sink for plasma-accessible targets. Sortilin and members of the low-density lipoprotein receptor-related protein family may suit extracellular clearance, aggregate removal or barrier transport, depending on cell context. Transferrin receptor 1 is widely used for uptake and blood–brain-barrier transport, but its recycling and transcytosis behavior must be redirected if degradation is intended. Disease-enriched handles, including prostate-specific membrane antigen, glypican-3, carbonic anhydrase IX and folate receptor alpha, can improve tissue selectivity, although their expression is often heterogeneous among patients, lesions and anatomical regions. Signaling-active cytokine, chemokine and hormone receptors may distinguish cell populations, but they can also alter pathways including JAK–STAT, PI3K–AKT, MAPK, calcium signaling, chemotaxis, desensitization and receptor downregulation. Attenuated ligands, antagonist-like binders, affinity tuning, altered subunit selectivity and geometric control may preserve uptake while reducing unwanted biological effects.

Molecular format adds another layer of control. Antibodies and other modular biologics offer high affinity, epitope selection and adjustable valency, but their size can limit penetration into solid tumors, dense extracellular matrices and protected compartments. For IgG-based constructs, Fc-receptor engagement, immune-complex behavior and neonatal Fc receptor recycling can also influence biodistribution, persistence and uptake independently of the intended mechanism. Compact small molecules or peptides may diffuse more readily and permit precise control of linker polarity, rigidity, plasma stability and pH sensitivity, yet many extracellular proteins lack suitable compact binders, and small constructs may be rapidly filtered, degraded or otherwise cleared before sufficient target capture occurs. Multivalent polymers, nucleic-acid assemblies, nanocages and vesicles can control ligand spacing and local concentration, but excessive size or valency may promote nonspecific uptake, clearance-organ accumulation, receptor sequestration or unstable endosomal complexes. Architectural novelty is not itself evidence of degradation; formats must be compared by sustained total target loss, lysosomal dependence, mechanistic clarity and translational performance.

Translating this strategy will require matching the dominant biological bottleneck to the design. Plasma-accessible soluble proteins may suit repeated systemic capture through a high-capacity clearance route, whereas tissue-resident membrane targets require penetration, selective cell access and sustained post-endocytic commitment. Targets behind anatomical barriers present two separate problems: crossing the barrier and achieving lysosomal degradation within the intended cell. Immune, inflammatory and endocrine applications also require monitoring of feedback, target resynthesis and receptor signaling. Safety assessments must examine competition with endogenous ligands, receptor capacity, off-tissue loss, inflammatory activation, immunogenicity and biodistribution, while manufacturing must control conjugation, valency, particle size, stability and batch consistency. Spatial proteomics, surface proteomics, multiplex imaging and single-cell profiling may help identify where target, recruited handle and degradative machinery coexist and distinguish delivery failure from routing failure. The review’s central conclusion is that the field must advance from demonstrating uptake to controlling intracellular fate, because only verified lysosomal destruction—not binding, disappearance from the cell surface or fluorescent uptake—establishes successful targeted lysosomal degradation.

Subject of Research: Design and validation of targeted lysosomal degraders for extracellular and membrane proteins

Article Title: Targeted Lysosomal Degradation of Extracellular and Membrane Proteins: From Receptor Hijacking to Programmable Endolysosomal Routing

Article References: Liu, K., Wang, X., Liu, X., He, C., Qian, D., Meng, X., & Zhu, L. (2026). Targeted Lysosomal Degradation of Extracellular and Membrane Proteins: From Receptor Hijacking to Programmable Endolysosomal Routing. Advanced Science, 13(58), Article e77675. https://doi.org/10.1002/advs.77675

Image Credits: AI Generated

DOI: 10.1002/advs.77675

Keywords: targeted protein degradation, lysosomal degradation, LYTACs, endolysosomal routing, membrane proteins, receptor recruitment, protein therapeutics, molecular design, drug discovery, extracellular proteins, Targeted, Lysosomal

Perovskite solar cells owe their appeal to a rare combination of traits: power conversion efficiencies that now rival established silicon technology, and a manufacturing route based on low-cost solution processing that can be printed, coated, or spin-cast at temperatures far below those needed for silicon wafer fabrication. Yet the technology remains haunted by stubborn bottlenecks. Devices degrade under sustained illumination, heat, and humidity; non-radiative recombination losses drain voltage; energy levels at interfaces misalign in ways that waste charge carriers; and producing large, uniform films across square meters of module area remains notoriously difficult. These problems, the review argues, share a common root in the delicate chemistry of the perovskite layer itself.

Ionic liquids, salts that remain liquid at or near room temperature, have emerged as one of the most versatile tools for addressing these weaknesses. Composed of bulky organic cations paired with organic or inorganic anions, they are essentially non-volatile, thermally robust, and electrically conductive. Crucially for perovskite researchers, both halves of the molecule can be tuned independently. The review emphasizes that this structural modularity is the key to their effectiveness: the cation backbone, the length of alkyl side chains, the type of functional substituents, and the coordination behavior of the anion collectively determine how, and how strongly, an ionic liquid interacts with the perovskite components.

The first major mechanism the authors dissect is crystallization control. Perovskite films form from solution, and the speed and orderliness of crystal growth determine whether the final film is riddled with grain boundaries and voids or dense and well-oriented. Ionic liquids can coordinate with lead ions and intermediate phases during deposition, slowing nucleation and guiding the formation of larger, more uniform grains. The review highlights work showing that ionic liquid additives enable high-quality crystallization even in air atmosphere, a significant practical advantage since perovskite processing has traditionally demanded inert-glovebox conditions. Viscosity effects, noted in earlier studies of ionic-liquid-assisted growth, also modulate how nanoparticles assemble into the final film.

Defect passivation is the second pillar. The surfaces and grain boundaries of perovskite crystals are littered with undercoordinated lead atoms and halide vacancies that act as traps for charge carriers, sapping efficiency through non-radiative recombination. Ionic liquids attack this problem from both ends of the molecule: the anion, whether a halide, pseudohalide, acetate, or fluorinated species, can bond to exposed lead sites, while cations such as imidazolium, pyrrolidinium, and pyridinium derivatives interact with the halide-rich side of the lattice. The review catalogs studies in which such dual-action passivation pushed fill factors above 83 percent in cesium-based cells and lifted efficiencies beyond 23 and even 25 percent, including air-fabricated devices reaching 25.11 percent efficiency.

Interfacial energetics form the third mechanism. A solar cell is a stack of dissimilar materials, and every junction between the perovskite and its transport layers can either help or hinder the flow of electrons and holes. Ionic liquids, with their permanent dipoles and tunable work functions, can realign energy levels at these buried interfaces, reducing voltage losses. The review describes strategies ranging from ionic liquid optimization of the interface between spray-coated nickel oxide and the perovskite, to hybrids of self-assembled monolayers and ionic liquids for buried interface modulation in tandem devices, to ionic liquid engineering that strengthens the perovskite/self-assembled-monolayer heterointerface itself.

Moisture resistance and long-term stability round out the picture. Water ingress is a primary degradation pathway for perovskites, and the hygroscopic character of ionic liquids is a double-edged sword that the review examines carefully. Some ionic liquids form protective encapsulating layers or stabilize one-dimensional perovskite phases at the surface that shield the underlying three-dimensional absorber. A landmark study cited in the review demonstrated that ionic liquids can dramatically improve the long-term operational stability of perovskite solar cells, and related work showed modules stabilized with ionic liquids exceeding 20 percent power conversion efficiency. The review also notes that in situ oligomerization of ionic liquids has produced robust encapsulation even in perovskite single crystals for X-ray detection, hinting that the same chemistry could harden photovoltaic devices.

The review’s most distinctive contribution is its insistence on structure-property relationships. Rather than treating ionic liquids as interchangeable additives, it categorizes them by chemical family, imidazolium, pyrrolidinium, ammonium, pyridinium, and protic variants among them, and links each family’s behavior to its molecular features. Alkyl chain length governs hydrophobicity and how deeply the cation inserts into the lattice; functional groups such as sulfonates, fluorine atoms, and Lewis base sites dictate coordination strength and passivation mode; and anion identity determines whether the additive manages iodine, moderates strain, or forms low-dimensional surface phases. This framework explains why, for example, a piperidinium salt famously stabilized high-efficiency perovskite cells in work published in Science, and why acetate-based ionic liquids excel at crystallization regulation in inorganic compositions.

The implications extend well beyond the laboratory. Ionic liquids have enabled printable mesoscopic cells exceeding 20 percent efficiency, improved the humidity tolerance of vacuum-deposited large-area modules, and even accelerated the oxidation of the widely used hole transport material Spiro-OMeTAD for more reproducible devices. They are also opening a greener processing route: protic ionic liquids have allowed researchers to formulate perovskite inks from water and alcohols for slot-die coating, moving the field away from toxic solvents. Machine learning is now being deployed to accelerate the search for optimal ionic liquid formulations, a development the review flags as a coming inflection point for the field.

Challenges remain before ionic liquid engineering becomes standard practice. The review acknowledges that the sheer diversity of possible cation-anion combinations makes systematic optimization difficult, that the long-term behavior of some additives under real-world operating conditions needs further scrutiny, and that the green credentials of ionic liquids themselves deserve honest reassessment rather than assumption. Still, the authors argue that the correlations they have mapped between molecular design and device performance provide the theoretical foundation needed to move from empirical discovery to deliberate engineering. If perovskite solar cells are to graduate from record-breaking lab curiosities to durable, bankable products on rooftops and solar farms, the humble ionic liquid, they suggest, may be one of the decisive ingredients.

Subject of Research: The role of ionic liquid molecular design in improving the efficiency and stability of perovskite solar cells

Article Title: Ionic liquids for perovskite solar cells: from molecular design to device performance

Article References: Sun, Z., Yang, L., Du, F., Wang, H., & Li, Z. (2026). Ionic liquids for perovskite solar cells: from molecular design to device performance. Journal of Materials Science. https://doi.org/10.1007/s10853-026-13946-8

Image Credits: AI Generated

DOI: 10.1007/s10853-026-13946-8

Keywords: perovskite solar cells, ionic liquids, defect passivation, crystallization, photovoltaics, interface engineering, device stability, molecular design, thin films, renewable energy, Ionic, liquids

The Branco Weiss Fellowship, formally known as the Society in Science program, is designed precisely for ideas of this kind. It supports postdoctoral researchers from any discipline who want to pursue unconventional, potentially transformative research questions at the academic institution of their choice, and it accepts no more than ten new fellows each year. With funding of up to CHF 600,000, roughly €635,000, over five years, the fellowship gives its recipients an unusual degree of freedom at a career stage when most researchers are still working within the frameworks of their senior colleagues. Mateo becomes only the second Spanish researcher to receive the award and one of the first to carry out the fellowship in Spain, a milestone that highlights the growing visibility of Spanish molecular science on the international stage.

For Mateo, the award represents more than financial security. It provides the opportunity to begin building his own research team and to establish an independent research programme at the Universidade de Santiago de Compostela, where he has worked since 2021 as a postdoctoral researcher in the groups of Diego Peña and Dolores Pérez. In a statement accompanying the announcement, he described the fellowship as an exceptional opportunity to explore a high-risk idea with the freedom and time needed to develop it, noting that carrying out the project at CiQUS, an environment that brings together synthetic chemistry, nanoscience and molecular materials, would allow questions to be addressed that would be difficult to tackle from a single discipline.

The scientific problem at the core of his project, named PhthalocyanYnes, begins with a paradox familiar to anyone who works with functional materials. Phthalocyanines are among the most chemically robust molecules in modern chemistry. These large, flat, nitrogen-rich macrocycles have optical properties that made them commercially valuable as pigments decades before anyone spoke of molecular electronics, and today they are regarded as highly attractive building blocks for functional materials ranging from organic semiconductors to catalysts. Their celebrated stability, however, is a double-edged sword. Once a phthalocyanine has been synthesised, its structure is remarkably difficult to modify, which means that exploring new variants typically requires designing and building each target molecule from scratch, a laborious process that limits how quickly new materials can be discovered.

Mateo’s proposed solution is to weaponise instability against stability. The project aims to introduce an aryne, an extremely reactive molecular intermediate that exists for only a fraction of a second, into these highly stable molecular systems. Arynes are among the most energetic species a synthetic chemist can generate in a reaction flask; they are so short-lived that they are never isolated but instead captured in situ by nearby molecules. The central challenge of the PhthalocyanYnes project is to tame this fleeting reactivity and harness it to selectively transform the phthalocyanine framework, for example through cycloaddition reactions, in which the aryne forms new rings by adding across the stable molecular scaffold. If the strategy works, it would effectively turn the molecules’ greatest weakness, their inertness, into a design opportunity.

The payoff, if the chemistry can be controlled, would be a fundamentally new way of accessing families of phthalocyanine-based structures. Rather than synthesising each member of a molecular family individually, researchers could prepare a common advanced precursor and then diversify it at a late stage of synthesis, a philosophy that has transformed drug discovery in medicinal chemistry but remains largely unexplored for these pigment-derived materials. Late-stage functionalisation of phthalocyanines would make the molecules substantially more versatile and programmable, allowing optical and electronic properties to be tuned almost modularly, in the way that software engineers modify code rather than rebuilding a program from first principles.

To reach that goal, the project will combine several techniques that rarely converge in a single laboratory programme. Synthetic chemistry will provide the molecular scaffolds and the aryne chemistry needed to modify them. Advanced spectroscopy will be used to characterise the products and follow the reactions as they unfold. Computational modelling will help predict which aryne additions are feasible and what properties the resulting structures will have. Single-molecule characterisation, a specialty that has grown rapidly at CiQUS in recent years, will allow individual molecules to be imaged and probed directly, revealing whether the intended structures have actually been achieved at the atomic scale. Together, these approaches will be applied to molecular architectures that are currently difficult to access, including asymmetric phthalocyanine–carbon nanostructure hybrids, extended molecular networks and nanographenes with tunable optical, electronic and magnetic properties.

The potential applications extend well beyond the laboratory curiosity that such exotic molecules might otherwise remain. Phthalocyanines and their derivatives already play important roles in organic photovoltaics, organic light-emitting diodes, sensors and catalysis, and their rigid, planar geometry makes them natural candidates for molecular components in next-generation devices. The chemistry developed in the PhthalocyanYnes project could open new opportunities for the development of functional molecular materials for applications in optoelectronics and quantum technologies, fields in which the ability to fine-tune the electronic structure of individual molecules is becoming increasingly important. Molecular networks and nanographenes with precisely controlled shapes and electronic properties are also of intense interest for quantum information research, where the behaviour of single molecules and single spins can carry information in ways that conventional materials cannot.

Mateo’s path to this award reflects the kind of interdisciplinary training that such ambitious projects demand. He joined CiQUS in 2021 as a postdoctoral researcher within the ERC Synergy Grant MolDAM project, supervised by Diego Peña, and has since continued his research at the centre, developing expertise at the intersection of organic chemistry, molecular design, nanoscience, molecular materials and surface chemistry. That combination, spanning the design of new reactions, the study of molecules on surfaces and the construction of functional materials, is precisely the skill set needed to attempt late-stage aryne chemistry on scaffolds as demanding as phthalocyanines. His independent programme will strengthen CiQUS’s ability to attract and support emerging scientific talent and to pursue high-risk research with transformative potential, according to the centre.

CiQUS itself holds the María de Maeztu Unit of Excellence accreditation, one of the highest recognitions available to research centres in Spain, along with the CIGUS recognition awarded by the Xunta de Galicia, and it receives financial support from the European Union through the Galicia FEDER 2021–2027 Programme. For the wider European research community, the award of a Branco Weiss Fellowship to a researcher based in Spain, and the decision to develop the project there rather than relocating to a northern European hub, signals a shift in where unconventional early-career science can flourish. If Mateo’s fleeting arynes can indeed be captured and put to work on some of the most stable molecules known to chemistry, the result could be a new generation of programmable molecular materials whose properties are written into their structures one selective reaction at a time.

Subject of Research: Late-stage aryne-based modification of phthalocyanine molecules for programmable functional molecular materials

Article Title: Luis M. Mateo awarded Branco Weiss Fellowship to develop new approach to molecular design at CiQUS

Article References: Luis M. Mateo awarded Branco Weiss Fellowship to develop new approach to molecular design at CiQUS. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Branco Weiss Fellowship, Luis M. Mateo, CiQUS, phthalocyanines, aryne chemistry, late-stage functionalisation, molecular design, nanoscience, optoelectronics, quantum technologies, ETH Zurich, Universidade de Santiago de Compostela

To understand why this matters, it helps to look at what happens inside a fuel cell. At the cathode, oxygen from the air must be converted through the oxygen reduction reaction, a chemically demanding process that requires a catalyst to proceed at useful speeds. Conventional fuel cells rely on platinum nanoparticles dispersed on carbon supports because platinum is exceptionally good at catalyzing this reaction. The problem is that platinum is extraordinarily expensive, geographically concentrated, and subject to severe resource constraints, all of which inflate the cost of fuel cell systems and limit how quickly they can be manufactured at scale. Any technology that removes platinum from the equation while preserving performance would therefore have immediate and far-reaching consequences for hydrogen power, portable energy, and decarbonized transport.

Anion-exchange membrane fuel cells offer a promising route around the platinum bottleneck. Unlike proton-exchange membrane fuel cells, which operate in acidic conditions that corrode most non-precious metals, AEMFCs run under mild alkaline conditions. That chemical environment allows a much wider palette of inexpensive catalyst materials to survive and function at the cathode. Among the candidates, metal phthalocyanines stand out. These are the classic blue pigments long used in dyes and inks, built around a central metal complex locked inside a large, flat, aromatic ring system. They are cheap, abundant, and structurally tunable, meaning chemists can modify their molecular framework to adjust how they interact with oxygen. Until now, however, molecular catalysts of this type had generally delivered insufficient power output and limited durability when installed in complete fuel cell devices rather than tested in idealized laboratory setups.

The Japanese-Israeli team’s breakthrough came from rethinking the pigment’s molecular architecture. The researchers synthesized two iron tetra-azaphthalocyanines, compounds in which nitrogen-containing heterocycles replace the peripheral benzene rings found in conventional iron phthalocyanine. This substitution is not cosmetic. Changing the electronic character of the ring surrounding the iron center alters how strongly the iron atom binds oxygen-containing intermediates during the reduction reaction, which in turn governs how fast and how efficiently the reaction proceeds. Two variants were prepared: one designated AZ-FT-30, based on FeAzPc-4N supported on conductive Ketjen Black carbon, and a more nitrogen-rich material designated AZ-FO-30, based on FeAzPc-8N8Me. The naming reflects the degree of nitrogen enrichment in each molecular structure.

A crucial early step was confirming that the pigment molecules were actually distributed in a useful form on the carbon support. Electron microscopy and elemental analysis showed that the iron-containing molecules were dispersed at the atomic and molecular scale across the carbon surface, without clumping into larger particles. This matters because aggregation would bury active sites and waste catalytic material. Equally important for the interpretation of the results, the two catalysts had nearly identical electrochemical surface areas, measured at 155.8 and 157.5 square meters per gram respectively. With the amount of accessible active material effectively held constant, the researchers could attribute differences in performance primarily to the intrinsic properties of the molecules themselves rather than to differences in how much catalyst was exposed to the reactants.

The fuel cell tests delivered striking results. Operating at 80 degrees Celsius, the AZ-FT-30 catalyst reached a peak power density of 744 milliwatts per square centimeter, already a strong figure for a platinum-free cathode. But the more nitrogen-rich AZ-FO-30 pushed the number to 902 milliwatts per square centimeter, which the manuscript reports as the highest power density recorded for an anion-exchange membrane fuel cell cathode based on a metal phthalocyanine. For context, that level of performance brings molecular catalysts much closer to the outputs typically associated with platinum-based systems, narrowing a gap that has long kept platinum-free options out of serious commercial consideration.

Durability, the second great hurdle for non-precious metal catalysts, also fared well in the tests. AZ-FO-30 operated continuously for 35 hours under a high constant load of 400 milliamperes per square centimeter, a demanding operating regime that accelerates degradation. Over that period, the cell’s voltage declined at an average rate of only 2.4 millivolts per hour. Sustained operation at high current density with such a modest decay rate suggests that the nitrogen-enriched molecular structure is not merely active but also robust enough to withstand the harsh conditions inside a working fuel cell, addressing one of the most persistent criticisms of molecular catalysts.

To explain why the modified pigments performed so well, the team turned to density functional theory calculations, carried out by Professor Maytal Caspary Toroker and her group at the Technion. The computational work linked the improved cell performance to molecular-scale oxygen binding. For adsorbed hydroxyl, a key intermediate in the oxygen reduction reaction, the distance between the iron atom and the oxygen atom decreased in a consistent order: it was longest for pristine iron phthalocyanine, shorter for AZ-FT-30, and shortest for AZ-FO-30. The shortest iron-oxygen distance in AZ-FO-30 indicates the strongest interaction at the iron active site among the three materials. Critically, the same trend persisted when the researchers included an explicit water molecule in the computational model, accounting for the aqueous environment at the cathode and strengthening the causal link between molecular design and the experimentally observed activity.

This alignment between computation and experiment is what elevates the study from an incremental materials report to a design principle. It suggests that the performance of phthalocyanine catalysts can be rationally tuned by controlling the electronic environment of the metal center, rather than discovered through trial and error. As Professor Yabu put it, the work shows that careful molecular design can close the performance gap between platinum catalysts and platinum-free catalysts, and that by tuning the structure of the blue pigment molecules the team strengthened the interaction at the active site and translated that into real gains in fuel cell performance. If the principle generalizes, chemists now have a clear lever to pull: enriching and modifying the ligand framework around the metal to optimize oxygen binding strength.

The broader implications extend across the clean energy landscape. Fuel cells are widely viewed as essential for decarbonizing sectors that batteries struggle to serve, including heavy trucking, shipping, and industrial power, and anion-exchange membrane technology in particular promises lower system costs because it can use cheaper components throughout. A high-performing, durable, platinum-free cathode built from pigment chemistry, one of the most mature and inexpensive classes of industrial molecules, could accelerate that transition substantially. Challenges certainly remain, including scaling up synthesis, validating long-term stability over thousands of hours, and integrating the catalysts into commercial stack designs. But the demonstration that a molecule borrowed from the artist’s palette can rival precious-metal performance marks a genuine milestone. The blue pigments that once colored canvases may now help color the hydrogen economy green.

Subject of Research: Nitrogen-enriched iron phthalocyanine catalysts for platinum-free anion-exchange membrane fuel cells

Article Title: A green future powered by blue pigments

Article References: A green future powered by blue pigments. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: fuel cells, phthalocyanine, platinum-free catalyst, oxygen reduction reaction, anion-exchange membrane, electrocatalysis, iron catalyst, ACS Catalysis, clean energy, hydrogen, molecular design, density functional theory

Most of the electronic devices in use today store, process, and transmit information using the charge of the electron. But electrons carry a second property that has long fascinated physicists: spin, an intrinsic form of angular momentum. Harnessing spin alongside charge is the goal of spintronics, a field that promises devices that are smaller, faster, and far more energy-efficient than their purely charge-based counterparts. The challenge lies in generating and controlling spin-polarized currents without bulky magnets or cryogenic conditions, which is where optical phenomena such as CPGE enter the picture.

The circular photogalvanic effect is a striking example of how light can do more than simply liberate charge in a material. When circularly polarized light—light whose electric field rotates in either a left- or right-handed spiral—falls on certain noncentrosymmetric materials, it can drive a net photocurrent whose direction flips depending on the handedness of the light. Because this effect is closely tied to spin-polarized electronic states, it offers a purely optical route to generating spin currents in materials that are not magnetized, making it especially attractive for studying and exploiting spin–orbit interactions, the quantum coupling between an electron’s motion and its spin.

Yet a fundamental question has clouded the field: when researchers measure a helicity-dependent photocurrent, is it truly coming from the bulk polarity of the crystal, or is it an artifact of surfaces and interfaces? In conventional CPGE measurements, signals from crystal surfaces often mix with bulk contributions, making it nearly impossible to determine the microscopic origin of the observed current. Professor Kouji Taniguchi of Science Tokyo, who led the new study, noted that CPGE is closely related to spin-polarized electronic states and has attracted attention as a route for generating spin-polarized photocurrents by light, but that this mixing of surface and bulk signals has made the microscopic origin difficult to pin down.

To resolve the ambiguity, the Science Tokyo team—including graduate student Ichi Naruse and Assistant Professor Po-Jung Huang of the Department of Chemistry—turned to two-dimensional organic–inorganic hybrid perovskites, abbreviated 2D-OIHPs. These layered crystals are built from alternating sheets of lead iodide and organic 1-(p-tolyl)ethylammonium cations. The design is deliberate: lead atoms endow the crystal with strong spin–orbit interaction, while the molecular cations carry permanent electric dipoles that confer a spontaneous macroscopic polarity on the whole crystal. In other words, the material combines the ingredients needed for strong CPGE with a tunable internal polarity set entirely by molecular arrangement.

The crucial experimental innovation was a symmetry-selective measurement geometry. The researchers illuminated the crystal with circularly polarized light at normal incidence—striking the surface at 90 degrees—and detected a photocurrent perpendicular to the crystal’s polarization axis that reversed direction when the light’s handedness was switched. When they rotated the electrodes by 90 degrees to measure along the polarization direction, the helicity-dependent current vanished entirely, exactly as the symmetry of the bulk crystal predicts. This directional asymmetry is the fingerprint of a bulk effect: surface contributions, which have different polarizations and spin orientations, are suppressed under normal incidence while the bulk response survives.

The importance of geometry became even clearer in control experiments. When the researchers tilted the light to a 45-degree incidence angle, helicity-dependent currents appeared in both the x- and y-axes, indicating that oblique illumination reintroduces contributions that obscure the intrinsic bulk signal. Normal incidence, the team concluded, is essential for cleanly isolating the bulk CPGE. The finding gives experimentalists a practical recipe: by simply choosing how light enters the crystal, they can separate bulk and surface photoresponses in atomically layered hybrid materials, a capability that should accelerate the characterization of spin-dependent properties across this growing material family.

To prove that bulk polarity truly dictates the direction of the photocurrent, the researchers went a step further and synthesized chiral-polar crystals containing either right-handed or left-handed versions of the organic molecule—mirror-image enantiomers. The chirality of the molecules determines the direction of the crystal’s overall polarization, so the two enantiomeric crystals exhibit opposite polarization directions. Remarkably, the sign of the CPGE photocurrent reversed between the two crystals, providing direct evidence that the molecular arrangement within the bulk sets the polarity of the crystal and, with it, the direction of the light-generated current. Flipping the handedness of the building blocks flips the response of the entire device.

The implications extend well beyond a single material system. By establishing that molecular design controls bulk polarity and thereby the direction of spin-polarized photocurrents, the study offers a rational strategy for engineering light-driven charge and spin responses from the bottom up. Taniguchi and his colleagues suggest that the findings could contribute to the development of helicity-sensitive photodetectors, spin-photonic devices, and next-generation opto-spintronic materials based on 2D hybrid perovskites. A photodetector that distinguishes left- from right-circularly polarized light, or a spin current source that requires nothing more than a laser and a cleverly designed crystal, are no longer distant concepts but plausible engineering targets.

The work, made available online on September 1, 2026, and published in Volume 26, Issue 36 of Nano Letters on September 16, 2026, also carries a broader lesson for materials science: symmetry is not merely a descriptive label but an operational tool. By aligning measurement geometry with the symmetry of the bulk crystal, researchers can silence unwanted surface signals and read out the intrinsic response of a material with unprecedented clarity. As hybrid perovskites continue to mature as a platform for optoelectronics, the ability to dial in polarity through molecular arrangement—and to verify it through symmetry-selective excitation—may prove to be one of the field’s most valuable design principles, bringing spin-based information technologies a step closer to practical reality.

Subject of Research: Bulk circular photogalvanic effect in two-dimensional organic–inorganic hybrid perovskites

Article Title: Molecular arrangement controls crystal polarity and reverses photocurrent direction

Article References: Molecular arrangement controls crystal polarity and reverses photocurrent direction. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: circular photogalvanic effect, hybrid perovskites, spintronics, crystal polarity, circularly polarized light, spin–orbit interaction, chiral crystals, photocurrent, 2D materials, opto-spintronics, molecular design, Nano Letters

The research team, led by Kiho Lee, Hayoon Lee, and Jongwook Park of the Department of Chemical Engineering, chose chrysene for a good reason: this four-ring polycyclic aromatic hydrocarbon emits at shorter wavelengths than anthracene, pyrene, or perylene, making it a natural candidate for the deep-blue emissive layers that future televisions will require. Recent experimental work has already hinted at the potential. A chrysene-anthracene hybrid host material achieved a photoluminescence quantum yield of 93.1 percent with 91.5 percent horizontal molecular orientation, while a chrysene-fluorene emitter delivered an external quantum efficiency of 6.84 percent in non-doped solution-processed devices. A third molecule, TPA-C-TP, produced a deep-blue electroluminescent device with CIE coordinates of (0.15, 0.07) and a peak emission wavelength of 439 nanometers.

The computational workflow began with a structural challenge that is easy to overlook. The seven studied compounds belong to the polycyclic aromatic hydrocarbon class in which phenyl substituents are attached through single bonds, giving the molecules rotational flexibility and therefore many possible conformers, each representing a distinct local minimum on the potential energy surface. To find the true global minimum, the team used global optimization algorithms within the ORCA quantum chemistry package, followed by rapid geometry screening with the semiempirical extended tight-binding method, and only then performed final energy minimization with full density functional theory. This multi-stage strategy matters because comparing an arbitrary conformer against experimental data would produce misleading conclusions about how the molecules actually behave in a device.

Two electronic structure approaches were compared in detail: the dispersion-corrected hybrid functional B3LYP-D3 with the Karlsruhe triple-zeta basis sets def2-TZVPP and def2-TZVPD, and the composite meta-GGA method r2SCAN-3c. Calculations were run both in the gas phase and with the conductor-like polarizable continuum model, an implicit solvation scheme, to test whether solvent effects changed the picture. The verdict was clear. HOMO energy levels computed with B3LYP-D3/def2-TZVPP deviated least from the experimental values measured by ultraviolet photoelectron spectroscopy on 50-nanometer-thick evaporated films, and the absorption and emission wavelengths predicted at this level of theory showed the highest consistency with measured spectra. Adding the solvation model or diffuse basis functions brought no significant improvement, a practical finding that could save other groups considerable computational expense.

The seven molecules fell into two structural families that revealed a clean design principle. The terphenyl series, TP-C-TP and TP-C-TPB, carries bulky phenyl-based side groups, while the diphenylamine series, including DPA-C-DPA, DPA-C-TPA, m-DPAC, p-DPAC, and DMTAC, attaches electron-donating amine units to the chrysene core. Optimized geometries showed dihedral angles between core and side groups of roughly 57.6 to 59.5 degrees for the phenyl-substituted molecules and 63.6 to 64.2 degrees for the amine-substituted ones. Angles near 60 degrees are no accident of geometry: they physically block the face-to-face stacking that organic emitters otherwise adopt, and stacked molecules quench each other’s light through strong intermolecular interactions. Methyl substitution on the amine groups barely moved the dihedral angles at all, indicating that the steric protection comes from the overall side-group architecture rather than the small methyl decorations.

The electronic consequences of these structural choices were equally revealing. Experimental LUMO levels of all seven molecules clustered tightly between -2.67 and -2.57 electronvolts, but the HOMO levels split into two distinct bands. The phenyl-substituted compounds sat at -5.88 and -5.84 electronvolts, while the amine-substituted derivatives ranged from -5.53 to -5.36 electronvolts, a shift of roughly 0.3 to 0.4 electronvolts driven by the electron-donating nitrogen lone pair. Adding methyl groups nudged the HOMO up by about another 0.1 electronvolt. The result was a band gap of 3.24 electronvolts for TP-C-TP and 3.18 for TP-C-TPB, versus a narrower 2.77 to 2.90 electronvolts for the amine family, with DMTAC showing the smallest gap of all at 2.77 electronvolts. Since a narrower gap translates directly into redder emission, these numbers let designers dial in the emission color before a single molecule is synthesized.

Perhaps the most visually intuitive tool in the study was the natural transition orbital analysis, which decomposes each electronic excitation into a hole orbital and a particle orbital. For the two terphenyl compounds, both hole and particle densities sat almost entirely on the chrysene core, signaling pure local excitation, the mechanism associated with high oscillator strengths and efficient fluorescence. For the five amine-substituted molecules, the hole localized on the side groups while the particle electron density migrated mainly to the chrysene core with some residual presence on the amines, a signature of hybridized local and charge-transfer character. The experimental photoluminescence quantum yields tracked this prediction: TP-C-TP and TP-C-TPB reached 35 and 53 percent in films, while the amine compounds climbed as high as 92 percent for m-DPAC and 90 percent for p-DPAC, with DMTAC measuring 73 percent even in dilute toluene solution.

Time-dependent DFT calculations extended the analysis to the wavelengths of light absorbed and emitted. Experimentally, the terphenyl compounds absorbed at 337 and 338 nanometers in solution, and the gas-phase B3LYP-D3/def2-TZVPP predictions matched those values closely. The amine derivatives absorbed further into the visible at 382 to 404 nanometers owing to intramolecular charge transfer, and here the calculations overestimated the wavelengths by about 20 to 30 nanometers, a discrepancy the authors attribute to the theory overestimating the energy elevation caused by the amine lone pair and thereby underestimating the gap between n-to-pi-star and pi-to-pi-star excited states. Oscillator strengths told a parallel story: as molecular length increased, the transition dipole moment grew proportionally, with TP-C-TPB reaching 0.84 compared with 0.49 for TP-C-TP, and the corresponding quantum yields rising from 35 to 53 percent. The same trend held in the amine series, where DPA-C-TPA’s oscillator strength of 0.55 against DPA-C-DPA’s 0.40 mirrored its quantum yield improvement from 32 to 64 percent.

On the emission side, the team compared vertical emission energies with adiabatic transition energies, the latter defined as the energy difference between the optimized first excited singlet state and the optimized ground state. The vertical emission wavelengths of 409 and 429 nanometers for the terphenyl compounds matched film measurements of 417 and 425 nanometers well, but for the amine-substituted derivatives it was the adiabatic values, calculated at 448 to 470 nanometers, that lined up with the measured film emissions of 454 to 469 nanometers. The practical lesson is that accurate emission prediction requires considering both transition types, and that emission color can be tuned by the position of methyl substitution, as shown by the 450 versus 459 nanometer emissions of m-DPAC and p-DPAC. Taken together, the study delivers a validated computational protocol and a molecular design strategy: bulky side groups at dihedral angles near 60 degrees suppress quenching, amine donors boost efficiency through hybrid excitation character but red-shift the color, and strategically placed phenyl units pull the emission back toward the deep blue that Rec. 2020 displays will demand.

Subject of Research: Density functional theory investigation of chrysene-derived deep-blue OLED emitter molecules

Article Title: Computational study on the optical and electronic properties of chrysene-derived deep-blue OLED molecules

Article References: Lee, K., Lee, H., & Park, J. (2025). Computational study on the optical and electronic properties of chrysene-derived deep-blue OLED molecules. Advances in Industrial and Engineering Chemistry, 1(1), Article 17. https://doi.org/10.1007/s44405-025-00017-w

Image Credits: AI Generated

DOI: 10.1007/s44405-025-00017-w

Keywords: OLED, chrysene, density functional theory, deep-blue emission, TDDFT, natural transition orbitals, HOMO-LUMO gap, photoluminescence, organic electronics, molecular design, Rec. 2020, computational chemistry

The new system, called SyntheMol-RL, is described in the journal Molecular Systems Biology. It is a significantly upgraded version of an earlier generative model, SyntheMol, which the same group used to design candidate antibiotics against Acinetobacter baumannii. The core idea behind both systems is the same: rather than screening existing compounds one by one, the AI builds new molecules from purchasable chemical building blocks using well-validated chemical reactions. This constraint guarantees that every molecule the model proposes can, in principle, be synthesized quickly and cheaply, a property that has long been the Achilles heel of generative drug design, where AI models frequently propose compounds that look good on paper but are practically impossible to make.

The key technical innovation in SyntheMol-RL is the replacement of the original Monte Carlo tree search algorithm with a reinforcement learning framework. In the earlier system, the tree search treated every possible combination of building blocks independently, scoring each node based on statistics about how often it had been explored and how well molecules built from it performed. That approach worked, but it could not learn patterns shared across chemically similar building blocks, which limited its search efficiency across enormous combinatorial spaces. The new reinforcement learning model instead uses a deep neural network as a value function that takes the chemical structures of building blocks as input and predicts the expected property score of molecules that could be assembled from them. Because the network generalizes across similar structures, it can navigate the chemical space far more intelligently, sampling promising nodes in proportion to their predicted value while still maintaining exploration.

A second major advance is multi-parameter optimization. Real drug discovery demands molecules that satisfy many properties simultaneously, not just one. In the team’s previous work, only two of six potent antibacterial compounds were soluble enough to be tested in animals, a bottleneck that motivated the new design. SyntheMol-RL combines separate reinforcement learning models, one for each property of interest, into a weighted value function whose weights adjust dynamically during generation. The system also dynamically tunes a temperature parameter that controls the balance between exploiting high-scoring building blocks and exploring diverse regions of chemical space, targeting a user-specified level of similarity among generated molecules. Ablation experiments showed that these dynamic mechanisms achieve optimal or near-optimal performance without manual fine-tuning, which would otherwise be highly sensitive and inconsistent between model variants.

To apply the system against S. aureus, the researchers first trained property prediction models on two datasets. For antibacterial activity, they physically screened an in-house library of 10,716 bioactive compounds against S. aureus RN4220, identifying 1,137 active molecules after statistical thresholding. For aqueous solubility, they used the AqSolDB dataset of nearly 10,000 molecules curated by the Therapeutics Data Commons. Two architectures were compared: Chemprop-RDKit, a graph neural network augmented with 200 molecular descriptors, and a simpler MLP-RDKit model using only the descriptors. The Chemprop-RDKit models performed slightly better and were selected as the fixed property predictors that score every molecule the generative model produces.

The researchers then ran two versions of SyntheMol-RL, one using the Chemprop architecture as the reinforcement learning value function and one using the MLP, alongside the older tree search version and a virtual screening baseline that evaluated 21 million randomly sampled molecules. Defining a hit as a molecule with a predicted antibacterial score of at least 0.5 and high predicted solubility, the RL-Chemprop variant generated hits at a rate of 11.6 percent and RL-MLP at 5.3 percent, compared with 3.0 percent for the tree search and a mere 0.006 percent for virtual screening. The comparison was deliberately fair: virtual screening was given roughly seven days of compute time, matching the slowest generative model. The team also benchmarked against two state-of-the-art generative systems, GFlowNet and REINVENT 4, which are not constrained to synthesizable chemical spaces. Although those models produced molecules with good predicted properties, medicinal chemists at the synthesis partners Enamine and WuXi offered limited synthesis options, with costs up to 62 times higher and timelines up to 5.7 times longer than the SyntheMol-RL compounds.

After filtering for novelty against known antibiotics, diversity, availability, and predicted toxicity, the team submitted 250 compounds for synthesis and obtained 196 unique molecules for laboratory testing. The results were striking. Eleven of 38 tested RL-Chemprop compounds and two of 41 RL-MLP compounds completely inhibited bacterial growth at concentrations of 8 micrograms per milliliter or lower, a hit rate of roughly 16 percent across the 79 SyntheMol-RL compounds synthesized. By contrast, none of the 44 randomly selected control molecules showed any activity up to the detection limit of 128 micrograms per milliliter, suggesting that ultra-large make-on-demand chemical libraries are not naturally rich in antibiotics and that conventional screening benchmarks may not apply to them. After a manual literature search for structural novelty, seven compounds remained as genuinely new antibacterial scaffolds.

One of those compounds, named synthecin, emerged as the standout. Although it shares some superficial features with salicylanilides, a class of known antibacterial agents, the researchers showed that it lacks the rigid hydroxybenzamide core and characteristic intramolecular hydrogen bonding of that class, instead incorporating a flexible aliphatic linker with a tertiary alcohol and trifluoromethyl group. All seven hit compounds retained potency against USA300, the most prevalent community-associated MRSA strain for skin infections, and against a panel of vancomycin-intermediate S. aureus isolates from the CDC database covering all major resistance mechanisms. Notably, the compounds showed no meaningful activity against other ESKAPE pathogens, indicating a narrow-spectrum profile that could spare beneficial microbiota and potentially slow the spread of resistance.

The team then moved synthecin into animal testing. Because S. aureus causes most skin and soft tissue infections, they first developed a simple assay called C.R.E.A.M., in which compounds formulated in a topical cream base are applied to MRSA-inoculated agar plates to evaluate chemical release and antibacterial effect. Synthecin produced the largest zone of inhibition among the seven candidates, and all seven compounds dissolved readily in the cream base, a practical payoff of optimizing solubility in silico. In a mouse wound infection model, mice pre-treated with cyclophosphamide were infected with roughly 21.5 million colony-forming units of MRSA USA300 and then treated topically with either vehicle or a 2 percent synthecin formulation at five time points over 20 hours. Vehicle-treated mice carried about 6.39 billion bacteria per gram of wound tissue at the endpoint, with visible inflammation, while synthecin-treated mice carried only about 51.4 million bacteria per gram, a burden comparable to untreated infection controls at the start of treatment, and their wounds showed no signs of inflammation.

The authors emphasize that SyntheMol-RL is not limited to antibiotics. Because it is compatible with any property predictor and any combinatorial chemical space, it can be applied across therapeutic domains, and it can even expand beyond single-reaction make-on-demand libraries to larger, multi-step synthetic spaces at the cost of higher expense. The work also highlights remaining challenges, particularly the need for more accurate property prediction models so that high-scoring computational designs translate more reliably into laboratory hits. Still, the journey from a 46-billion-molecule search space to a structurally novel compound that suppresses an MRSA wound infection in mice, accomplished with a 16 percent experimental hit rate, marks a compelling demonstration that reinforcement learning guided generative design can bridge the long-standing gap between computational molecular design and real-world drug discovery.

Subject of Research: Reinforcement learning-based generative AI for designing synthesizable antibiotics against drug-resistant Staphylococcus aureus

Article Title: SyntheMol-RL: a flexible reinforcement learning framework for designing easily synthesizable antibiotics

Article References: Swanson, K., Liu, G., Catacutan, D. B., McLellan, S., Arnold, A., Tu, M. M., Brown, E. D., Zou, J., & Stokes, J. M. (2026). SyntheMol-RL: a flexible reinforcement learning framework for designing easily synthesizable antibiotics. Molecular Systems Biology, 22(6), 833-867. https://doi.org/10.1038/s44320-026-00206-9

Image Credits: AI Generated

DOI: 10.1038/s44320-026-00206-9

Keywords: SyntheMol-RL, reinforcement learning, generative AI, antibiotic resistance, MRSA, Staphylococcus aureus, drug discovery, molecular design, synthesizability, synthecin, chemical space, preclinical validation

The achievement matters because the refractive index, denoted n, governs how efficiently a material can bend, focus and manipulate light. A higher index permits thinner lenses, stronger light confinement in waveguides, and higher-contrast interference and diffraction structures. In the near-infrared region, where imaging, sensing, biomedical diagnostics and telecommunications flourish, the difference between a polymer at n = 1.6 and one at n = 2.53 is transformative. Optical components that previously demanded millimeters of dense glass could, in principle, be made from a fraction of the thickness of a flexible plastic film, opening the door to ultrathin infrared cameras, conformable sensors and lightweight wearable optics.

The secret of K153 lies in its chemistry. The researchers, led by Hongbin Chen, Jianrong Guo and Chaobin He of the National University of Singapore, together with collaborators in China and Singapore, designed the polymer around carefully placed cyano groups — the linear carbon–nitrogen substituents known for their strong electronic character. According to the team, the outstanding refractive index arises from two synergistic effects induced by these linear cyano groups: enhanced polarizability, which directly increases how strongly the material’s electrons respond to passing light waves, and strengthened intermolecular interactions that pack the chains into a denser, more optically responsive solid. In simple terms, the cyano groups give the polymer both more responsive electrons and a more tightly organized structure, and both effects push the refractive index upward.

Boosting the index is only half of the problem. The other half is infrared transparency, and here most polymers fail spectacularly. Ordinary organic molecules contain bonds — carbon–hydrogen, carbon–oxygen, nitrogen–hydrogen — that vibrate at frequencies matching infrared light, absorbing it strongly and creating the characteristic absorption bands that make plastics useless for much of the infrared. The team circumvented this by designing symmetric molecular architectures for the polymer’s constructing units. Symmetry suppresses the infrared-active vibration modes responsible for light loss, so the material avoids absorbing the very wavelengths it is meant to transmit. The result is a polymer that combines a record-high refractive index with outstanding transparency in the near-infrared regime, a combination that the authors note lags far behind inorganic analogues in essentially all prior all-organic materials.

The practical demonstrations reported in the study suggest that K153 is not merely a laboratory curiosity. The researchers fabricated thin films of the polymer and showed that they deliver high-quality infrared imaging, meaning the material can serve as a functional optical medium rather than simply a passive coating. The films also exhibited impressive environmental tolerance, surviving conditions that would degrade many organic optical materials, and extraordinary flexibility, bending without cracking or losing optical performance. That mechanical resilience is precisely what inorganic infrared optics cannot offer: chalcogenide glasses and semiconductor windows are brittle, heavy and expensive to shape, whereas a polymer film can be rolled, wrapped around curved surfaces, or integrated into flexible devices.

Two further capabilities distinguish the new material. First, the refractive index of K153 is tunable through chemical doping, giving optical engineers a dial they can turn to match specific design requirements — a flexibility unavailable in fixed-composition glasses. Second, the polymer demonstrates nanoimprintability: it can be molded at the nanoscale using nanoimprint lithography, allowing researchers to stamp fine photonic structures such as gratings, microlens arrays and meta-optical textures directly into the film. Combining high index with nanoscale patterning is the essential recipe for flat optics, and a polymer that supports both processes cheaply could dramatically lower the cost of advanced infrared components.

The broader context explains why this result has generated excitement beyond the immediate field. Inorganic high-index materials — from titanium dioxide nanoparticles to silicon photonics — have fueled a wave of metalens and metasurface research, but their fabrication is demanding and their integration with flexible or biological systems is awkward. Sulfur-containing polymers developed through inverse vulcanization have pushed organic indices higher and improved infrared transparency, yet they typically remain below the inorganic benchmark or sacrifice transparency in key bands. K153, the authors report, surpasses a refractive index of 2.25 — the level associated with chalcogenide glasses and CdS/ZnS/ZnSe optics — while remaining a fully organic, ductile, lightweight polymer.

The molecular design philosophy behind the work may prove as influential as the material itself. Rather than doping a polymer with high-index inorganic particles, which often causes scattering and haze, the team engineered the index into the polymer backbone through targeted cyano substitution, an approach the authors describe as tailored cyano engineering. Because the linear cyano group simultaneously raises polarizability and strengthens intermolecular packing without introducing heavy inorganic domains, the material stays optically homogeneous and transparent. The study, according to its authors, demonstrates that deliberate molecular-structure optimization can deliver a dramatic increase in refractive index, representing a decisive step toward using all-organic polymers for infrared applications previously considered the exclusive territory of inorganic materials.

What comes next could reshape several industries at once. Near-infrared imaging is expanding rapidly, from night vision and autonomous vehicle perception to medical diagnostics that exploit the deep tissue penetration of shortwave infrared light. Flexible, transparent, high-index polymer films could enable conformal infrared lenses, ultralight thermal cameras, wearable NIR sensors and infrared-transparent protective coatings that are currently impractical with brittle glass. Meanwhile, the demonstrated combination of tunability, nanoimprintability and environmental robustness suggests K153-type polymers could become a platform material for photonic integrated circuits, diffractive optics and augmented-reality systems operating in the infrared. If the promise of cyano-engineered organic polymers scales from laboratory films to manufactured components, the rigid, heavy glass lens — an icon of optics for centuries — may finally face a genuinely flexible rival.

Subject of Research: An all-organic cyano-substituted polymer with a large near-infrared refractive index and high infrared transparency for optical imaging applications.

Article Title: All-organic polymer with large refractive index in the near-infrared

Article References: Chen, H., Guo, J., Ma, K., Miao, X., Liu, S., Huang, B., Self, T. J., Vinod, K., Abdelraouf, O. A. M., Long, G., He, T., Meng, L., Zhang, Y., & He, C. (2026). All-organic polymer with large refractive index in the near-infrared. Nature Photonics. https://doi.org/10.1038/s41566-026-02000-3

Image Credits: AI Generated

DOI: 10.1038/s41566-026-02000-3

Keywords: high refractive index polymer, all-organic polymer, near-infrared transparency, cyano substitution, infrared imaging, nanoimprint lithography, optical materials, chalcogenide glass, flexible photonics, chemical doping, molecular design, Nature Photonics