The research centers on a novel co-crystal engineering strategy, leveraging the unique properties of benzoguanamine—a neutral molecule seldom explored in perovskite chemistry—as a linker within low-dimensional perovskites. Traditional methods typically utilize ionic molecules to form these 2D layers; however, these ionic components can contribute to instability through ion migration and environmental degradation. By replacing these conventional ionic linkers with benzoguanamine, researchers have forged a co-crystal structure that not only sustains high photovoltaic performance but also significantly bolsters the operational stability of the devices.

Applying this co-crystal interlayer onto the perovskite active layer facilitates exceptional power conversion efficiencies (PCEs) that rival, if not surpass, those achieved with standard 2D perovskite structures. Specifically, small-area solar cells fabricated with this co-crystal engineering approach have demonstrated outstanding PCEs of 23.4%. Beyond the laboratory-scale devices, the researchers successfully scaled the technology to solar modules with active areas measuring 9.0 cm² and 48 cm², which achieved PCEs of 23.1% and 18.5%, respectively. These figures mark a significant stride towards the practical deployment of high-performance perovskite solar modules in real-world applications.

What sets this development apart is not only the impressive efficiency but the unprecedented operational stability exhibited by these co-crystal engineered modules. The solar modules retained more than 95% of their initial efficiency following over 5,000 hours of continuous one-sun light soaking at maximum power point conditions—a stress test that simulates extended exposure to sunlight under real operating conditions. Moreover, when subjected to ultraviolet (UV) radiation exposure exceeding 1,000 hours, the modules maintained over 98% of their initial efficiency, highlighting their robustness against UV-induced degradation mechanisms, which are typically detrimental to perovskite materials.

Thermal stability, another critical parameter for photovoltaics especially in harsh climates, has also been markedly improved by this co-crystal approach. Under continuous thermal stress at 85°C for more than 5,000 hours, the solar modules retained over 91% of their initial efficiency. This level of heat endurance is a transformative milestone, illustrating that the molecular design within the 2D perovskite interlayers can fundamentally enhance the structural and chemical stability of the entire device.

The success of this work is rooted in the careful molecular engineering of the perovskite interface. Benzoguanamine, being a neutral molecule, forms strong hydrogen bonding and van der Waals interactions within the co-crystal network. This contrasts markedly with ionic molecules whose interactions may be more prone to disruption via environmental factors like moisture and thermal fluctuations. As a result, the benzoguanamine-based co-crystal provides a stable scaffold that inhibits ion migration—a well-known degradation pathway in perovskite solar cells—thus preserving the integrity of the perovskite lattice over extended operation.

Fundamental photophysical characterizations demonstrate that the presence of the benzoguanamine linker does not hinder but rather optimizes charge transport across the interlayer. This is paramount because maintaining efficient charge extraction is essential for retaining high photovoltaic efficiency. The co-crystal engineered interlayer ensures a seamless electronic interface between the perovskite absorber and transport layers, minimizing recombination losses and promoting sustained device performance.

This pioneering technique signals a paradigm shift in the design principles for perovskite solar cells. Instead of merely focusing on the perovskite absorber composition or device encapsulation to boost stability, this approach innovates at the molecular scale by tailoring the chemistry of the interlayer itself. It bridges the gap between efficiency and stability—a trade-off that has long hampered perovskite solar technology—and effectively rewrites the roadmap toward commercial viability.

Scaling up from lab-scale cells to larger modules often results in performance penalties due to inhomogeneities and defect states; however, the co-crystal interlayer appears to alleviate these issues. The solar modules fabricated show minimal efficiency loss compared to their smaller counterparts, demonstrating the robustness and uniformity of the co-crystal layer deposition. This scalability is a crucial step toward integrating perovskite solar modules into the existing photovoltaic market.

The resilience to prolonged UV exposure is particularly noteworthy, as UV damage can generate trap states and catalyze chemical degradation within the perovskite lattice. The neutral molecular framework of the co-crystal likely imparts a UV-filtering or UV-resilient quality to the interlayer, protecting the underlying perovskite from photochemical deterioration and thereby extending device lifetime.

Moreover, the thermal endurance achieved suggests that the co-crystal interlayer can counteract thermal expansion mismatches between the perovskite and adjacent layers, a common issue that leads to mechanical failure and interface delamination. This implies that the benzoguanamine-based co-crystal forms a mechanically robust and thermally stable interface that can withstand the thermal cycling conditions typical in outdoor environments.

In essence, this study embodies a synthesis of chemistry, materials science, and device engineering to address the critical challenges that have limited the widespread adoption of perovskite solar technologies. By unlocking the potential of neutral molecule-based co-crystals, the work propels the field toward sustainable, efficient, and durable solar energy solutions.

Looking ahead, the implications of this research extend beyond photovoltaics. The co-crystal engineering approach may inspire analogous strategies in other optoelectronic devices where stability and performance are paramount, including light-emitting diodes, photodetectors, and sensors. The molecular design principles elucidated here could become a universal toolkit for crafting next-generation materials with tailored functionalities.

This breakthrough was achieved through a multidisciplinary collaboration combining synthetic chemistry, advanced materials characterization, device fabrication, and longevity testing. These collective efforts underscore the critical importance of integrating diverse scientific disciplines to overcome entrenched technical roadblocks.

Ultimately, the research exemplifies how fundamental molecular manipulation can translate directly into tangible technological advancements, offering a compelling vision for the future of solar energy that is both highly efficient and reliably stable under real-world conditions. It paves the way for perovskite solar modules to transition from laboratory curiosities to commercially entrenched clean energy solutions.

As the world grapples with the urgent need to transition to renewable energy, innovations such as this co-crystal engineering strategy provide a beacon of hope. They illustrate how meticulous molecular engineering can solve practical challenges, enabling perovskite solar cells to meet their promise as a cornerstone of global sustainable energy infrastructures.

Subject of Research:
Perovskite solar cells and interfacial engineering to enhance efficiency and stability

Article Title:
Co-crystal engineering of a two-dimensional perovskite phase for perovskite solar modules with improved efficiency and stability

Article References:
Yaghoobi Nia, N., Zendehdel, M., Paci, B. et al. Co-crystal engineering of a two-dimensional perovskite phase for perovskite solar modules with improved efficiency and stability. Nat Energy (2025). https://doi.org/10.1038/s41560-025-01903-9

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s41560-025-01903-9

Keywords:
Perovskite solar cells, two-dimensional perovskites, co-crystal engineering, benzoguanamine, photovoltaic efficiency, operational stability, ultraviolet stability, thermal stability, power conversion efficiency, interface engineering

Silicon solar cells have long been the cornerstone of the global push towards sustainable energy solutions. However, despite extensive research over decades, achieving efficiencies near the theoretical limit has remained elusive. Key efficiency losses are often traced back to recombination events—processes where charge carriers recombine prematurely, dissipating the potential electrical energy as heat. These losses are particularly pronounced at the cell interfaces and contact regions, presenting a formidable barrier to performance improvements. The reported device achieves a remarkable power conversion efficiency of 27.81%, which corresponds to nearly 95% of the theoretical efficiency ceiling predicted for silicon photovoltaics.

The novel hybrid IBC design integrates high-temperature and low-temperature process techniques in a synergistic fashion. This enables precise control over the silicon surface states and electrical contacts, effectively suppressing carrier recombination at these critical junctions. Of particular note is the use of laser-treated tunneling contacts, which facilitate efficient charge extraction with minimal resistive and recombinative losses. The finesse of this approach is reflected in the staggering fill factor recorded: 87.55%, reaching nearly 98% of its theoretical potential. Such an elevated fill factor is pivotal, as it directly influences the maximum power output possible from the cell under standard test conditions.

Central to this breakthrough is a sophisticated model that quantitatively links the ideality factor—a fundamental parameter describing diode behavior in solar cells—to specific carrier loss mechanisms. By analyzing the ideality factor, researchers were able to unravel the complex interplay between carrier recombination occurring within the bulk silicon and at the surfaces. This nuanced understanding clarifies the precise pathways by which recombination undermines cell performance, providing a roadmap to further optimize the device architecture beyond current benchmarks. The model not only aids in diagnosing fill factor limitations but also offers predictive insights critical for scaling up production.

The hybrid IBC cell represents a shift from conventional back contact designs. Whereas prior designs focused predominantly on optimizing either surface passivation or contact resistance independently, this study uniquely converges both aspects through innovative process integration. The all-surface passivation technique utilized here ensures that silicon surfaces remain electronically inert, curbing surface recombination velocities to unprecedentedly low levels. When paired with laser-induced contact structures that form atomically sharp interfaces, the result is a device with exceptionally low recombination current and near-ideal electrical characteristics.

A key enabler of this technology is the precise laser doping technique that forms the tunneling contacts. This method involves targeted laser irradiation that locally modifies the silicon lattice and dopant concentrations, creating ultra-thin, heavily doped layers. These layers act as quantum tunneling barriers for carriers, allowing swift and efficient majority carrier flow while blocking minority carriers prone to recombination. This dual function is essential for maximizing current collection while maintaining the cell’s open-circuit voltage—a delicate balance that historically has been difficult to achieve simultaneously.

Beyond the scientific and technical merits, the hybrid IBC cell holds great promise for practical deployment. The fabrication processes developed are compatible with industrial-scale manufacturing, an essential consideration for any technology seeking mass adoption. The combination of high and low-temperature steps respects thermal budgets associated with silicon wafer processing, ensuring compatibility with existing photovoltaics infrastructure. Moreover, the innovations presented defy the often-observed trade-offs between efficiency and manufacturability, charting a path towards commercial devices that do not compromise on either front.

This solar cell advance directly addresses a critical global imperative. Current solar energy installations—while impressive in scale—still operate below their maximum potential efficiencies, impeding the pace at which fossil fuel dependence can be reduced. By closing the gap to theoretical limits, technologies like this hybrid IBC cell can significantly enhance the output and cost-effectiveness of solar power plants. Such progress is vital in meeting ambitious carbon neutrality goals worldwide and ensuring affordable access to clean energy, especially in emerging economies.

Importantly, the research highlights the synergy between experimental advances and theoretical modeling. The comprehensive framework linking device-level performance metrics with microscopic recombination mechanisms showcases the power of integrating experiment with theory. This multidisciplinary approach not only accelerates innovation but ensures that improvements are grounded in fundamental understanding, providing confidence in the scalability and longevity of the technology.

Looking forward, the authors suggest avenues for further refinement, including the exploration of alternative surface passivation chemistries and refined laser doping protocols. Additionally, integrating this hybrid IBC design with emerging tandem solar cell architectures could push efficiencies even higher, utilizing complementary absorber materials atop silicon to harvest a broader spectrum of sunlight. As the photovoltaic research community digests these findings, the implications resonate widely: breaking long-standing efficiency barriers in silicon photovoltaics is now more attainable than ever.

In summary, this pioneering work presents a Silicon solar cell that achieves a remarkable 27.81% power conversion efficiency and a fill factor nearing the theoretical maximum. Through a hybrid back-contact configuration that harmonizes advanced passivation and laser-induced tunneling contacts, the scientists succeeded in addressing fundamental recombination losses and contact resistances. The work not only advances silicon photovoltaics toward their performance ceiling but also lays a robust foundation for scalable industrial application, marking a significant milestone in the quest for sustainable energy solutions.

As the sun continues to power our planet, innovations such as this are vital in harnessing its energy more effectively and economically. This achievement underscores how meticulous engineering at the atomic and device levels can translate into transformative impacts on global energy systems. The future of solar energy is brighter than ever, illuminating the pathway to a truly sustainable energy paradigm.

Subject of Research: Silicon solar cell efficiency enhancement via hybrid interdigitated back-contact design.

Article Title: Silicon solar cells with hybrid back contacts.

Article References: Wang, G., Yu, M., Wu, H. et al. Silicon solar cells with hybrid back contacts. Nature 647, 369–374 (2025). https://doi.org/10.1038/s41586-025-09681-w

Image Credits: AI Generated

DOI: 13 November 2025

The principle behind radio-photovoltaic cells hinges on the direct conversion of high-energy beta particles emitted by radioisotopes into electrical energy, circumventing the need for intermediate thermal cycles or mechanical components. ^90Sr, a widely available fission byproduct known for its potent beta radiation, emerges as a compelling candidate for such applications. However, conventional radioisotope-powered devices have traditionally struggled with poor efficiency and rapid material degradation due to radiation damage. The current research addresses these challenges by leveraging advanced photonic engineering techniques, notably the incorporation of waveguide structures to capture and concentrate the emitted photons more effectively.

At the core of this novel design lies a waveguide light concentration architecture that channels the luminescent output generated by beta interactions within a scintillating layer toward the photovoltaic junction with minimal energy loss. Unlike typical setups where re-emitted photons scatter randomly, the waveguide confines and directs light, increasing the probability of photon absorption by the solar cell material. This clever manipulation of light not only enhances the quantum efficiency of the device but also mitigates the detrimental effects of self-absorption, a common limitation in radio-luminescent systems.

The fabrication process of these radio-photovoltaic cells involves the meticulous layering of scintillators, waveguides, and semiconductor photovoltaic elements. The scintillator, strategically doped with high-Z elements to maximize beta particle interactions, generates visible photons upon ^90Sr decay. These photons enter the waveguide layer, an engineered optical conduit that substantially reduces photon escape. Careful design parameters optimize the refractive indices and geometrical configuration, ensuring that the generated light traverses the waveguide via total internal reflection toward an adjacent photovoltaic junction, where it is converted into electric current.

One of the critical challenges overcome by this work is the stability of the device under sustained radioactive bombardment. The researchers employed radiation-hardened materials and encapsulation techniques to preserve the structural and functional integrity of the waveguide and photovoltaic layers. Moreover, the device exhibits a remarkable capacity for self-healing and maintaining performance, attributed to the dynamic redistribution of charge carriers and the inherent robustness of the semiconductor matrix. This durability dramatically extends the lifespan of the radio-photovoltaic cell, addressing a major bottleneck in previous iterations.

Performance metrics reported in the study reveal a dramatic leap in conversion efficiency, surpassing previous benchmarks for ^90Sr-based systems by a significant margin. The optimized waveguide structure facilitates enhanced luminescence extraction, enabling the photovoltaic junction to achieve peak responsivity in the spectral region most relevant to the scintillation emission. Experiments demonstrate stable power output over prolonged operational periods, indicating the potential for real-world deployment in niche applications requiring compact, long-lived power sources.

The implications of such high-efficiency radio-photovoltaic cells are immense, particularly for environments where traditional solar energy harvesting is impractical or impossible. Space missions, deep-sea exploration probes, and remote sensing devices can all benefit from this dependable power generation method, which functions independently of sunlight or atmospheric conditions. The scalability of the technology also opens avenues for its integration into hybrid systems, complementing existing renewable infrastructure to deliver continuous baseline power.

Beyond immediate practical applications, this research exemplifies a successful marriage of nuclear physics, materials science, and photonic engineering. The synergy achieved by combining a precise understanding of beta decay processes with nanoscale waveguide design sets a new standard for interdisciplinary innovation. The team’s multidisciplinary approach, incorporating advanced simulation and experimental validation, underscores the importance of holistic problem-solving strategies in tackling complex energy challenges.

Notably, the researchers conducted extensive simulations to model photon propagation within the waveguide, tuning parameters such as thickness, geometry, and refractive index contrasts for optimal light guidance. These theoretical findings informed fabrication protocols, resulting in physical prototypes that consistently mirrored predicted performance. This iterative loop between modeling and experimentation accelerated development cycles, offering a roadmap for future enhancements in radio-photovoltaic technology.

From a materials science standpoint, the choice of semiconductor components was pivotal. The researchers selected wide bandgap materials with high radiation tolerance, ensuring that energetic beta particles would not prematurely degrade the device. Furthermore, surface passivation techniques were applied to the photovoltaic interface, minimizing non-radiative recombination and enhancing carrier collection efficiency. These layers collectively tightened the balance between durability and performance, a critical requirement for long-term operation in radioactive environments.

Environmental considerations also played a key role in shaping the device architecture. By localizing the radioactive source within a compact, shielded cassette and employing non-toxic semiconductor and scintillator materials, the researchers drastically reduced hazards associated with radioactive waste and potential leaks. This attention to safety and sustainability makes the radio-photovoltaic cells viable candidates for widespread adoption beyond specialist applications, potentially transforming the energy landscape in regions with limited grid infrastructure.

Looking forward, the team envisions integrating these radio-photovoltaic cells into modular power units, readily deployable in diverse contexts. Such modules could power sensor networks, autonomous systems, or emergency infrastructure, delivering reliable electricity where conventional batteries falter. Additionally, ongoing improvements in material synthesis and waveguide fabrication techniques promise to further elevate conversion efficiencies, pushing the frontier of nuclear-powered photovoltaic devices into new territory.

This pioneering work also sparks renewed interest in revisiting other radioisotopes as potential energy sources. While ^90Sr remains attractive due to its beta emission spectrum and availability, alternative isotopes with longer half-lives or different decay modalities could be tailored to niche energy needs, opening an expanded toolkit for customized power solutions. The modular waveguide-concentrator paradigm introduced here provides a versatile platform adaptable to such future explorations.

In sum, the demonstration of high-efficiency ^90Sr radio-photovoltaic cells based on waveguide light concentration heralds a transformative chapter in energy harvesting technologies. By ingeniously channeling radioactive emissions into usable electricity with enhanced efficacy and durability, the research shatters preconceived limitations of nuclear-powered photovoltaics. This breakthrough stands to impact a broad spectrum of industries, from outer space exploration to sustainable terrestrial energy systems, signaling a powerful stride toward a diversified and resilient energy future.

As the scientific community digests these findings, the ripple effects of this innovation are expected to stimulate further research and investment at the nexus of photonics, nuclear energy, and materials engineering. The potential to power devices autonomously for decades without relying on external inputs could redefine energy autonomy across multiple domains. It is a vivid reminder that even the most potent natural phenomena, when harnessed with precision and creativity, can unlock new avenues for human advancement.

Subject of Research:

Article Title:

Article References:
Jiang, T., Li, S., Yao, W. et al. High-efficiency ^90Sr radio-photovoltaic cells based on waveguide light concentration structure. Light Sci Appl 14, 214 (2025). https://doi.org/10.1038/s41377-025-01875-1

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s41377-025-01875-1

Keywords:

Perovskite solar cells represent a revolutionary approach in the realm of photovoltaic technology. They exhibit remarkable light-absorbing capabilities, which make them a solid contender to overcome the limitations of conventional crystalline silicon solar cells. While silicon-based cells dominate the market due to their affordability and widespread manufacturing capabilities, they have begun to plateau in efficiency as they reach their theoretical limits. In contrast, tandem solar cells that pair silicon with perovskite materials have emerged as promising alternatives, significantly enhancing overall energy conversion rates.

The unique composition of tandem solar cells allows for greater versatility in application, particularly in sectors where the adaptability and lightweight properties of solar panels are essential. Traditional perovskite/silicon cells, despite achieving efficiency rates as high as 34.6%, face challenges concerning weight and damage susceptibility. These problems hinder their application in contexts such as aerospace and automotive industries, where weight considerations and structural integrity are critical.

In an effort to address these challenges, the innovative work by the KIER research team has led to the development of flexible thin-film perovskite/CIGS tandem solar cells. CIGS, known for being lightweight and flexible, is particularly suitable for integration into curved surfaces represented in modern architecture, vehicles, and other innovative applications. However, previous iterations suffered from lower efficiency rates and complex manufacturing processes, creating barriers to market readiness.

The KIER team’s novel approach involved a simple lift-off process. This methodology entails coating a polyimide layer onto a glass substrate before fabricating the perovskite/CIGS tandem solar cell atop the polyimide. The lift-off process allows for stable and uniform layer deposition which leads to significantly higher reproducibility and efficiency compared to traditional methods. The rigid glass substrate utilized in this process enhances the stability during fabrication and ultimately contributes to the performance improvement of the solar cells.

Moreover, the team identified a critical improvement mechanism during the fabrication process that involves managing the diffusion of alkali metals from the glass substrate into the CIGS layer. Excessive diffusion of potassium, in particular, can introduce defects in the absorber layer, negatively impacting the overall efficiency of the solar cells. To combat this issue, the researchers leveraged computational science to predict that the polyimide layer could effectively suppress potassium diffusion, resulting in fewer defects and a marked increase in performance.

Not only did the innovative fabrication process contribute to efficiency gains, but it also provided the new cells with outstanding durability. The research team undertook rigorous mechanical testing, performing 100,000 bending cycles to evaluate the resilience of the solar cells. Impressively, the cells maintained an efficiency of 97.7% post-testing, showcasing their robustness and suitability for challenging real-world applications.

Dr. Inyoung Jeong emphasized the significance of this achievement, noting that it lays the groundwork for future advancements toward a goal of achieving 30% efficiency in ultralight flexible solar cells. The implications of this work are vast, with the potential to expand applications in renewable energy, particularly in highly portable and adaptable modules.

Dr. Kihwan Kim, another prominent figure in the research, highlighted the power-to-weight ratio associated with the new solar cells, stating it is approximately ten times greater than traditional perovskite/silicon tandem solar cells. This breakthrough promises to enable innovative applications in demanding environments, such as in building exteriors and on vehicles, where every gram counts, and efficiency is paramount.

The research results were published in the prestigious journal Joule, which underscores the high impact of this discovery on the field of energy and materials science. This accomplishment was made possible through a collaborative effort involving distinguished scholars like Professor Tae Kyung Lee of Gyeongsang National University and Professor Hae-Jin Kim of Yonsei University, showcasing the strength of collaborative research in driving technological advancements.

As renewable energy solutions continue to shape a sustainable future, the ultra-lightweight flexible perovskite/CIGS tandem solar cells developed by KIER serve as a formidable step toward overcoming existing barriers in solar cell technology. Their impressive efficiency, durability, and lightweight nature present an exciting prospect for the future of energy generation, particularly as industries strive for greener alternatives in a world increasingly reliant on sustainable solutions.

With ongoing efforts to refine manufacturing processes and enhance the stability of these solar cells, the KIER research team aims to fortify the competitiveness of the renewable energy sector. This breakthrough not only contributes to advancing solar technology but also signals the potential for widespread adoption of renewable energy solutions across various industries, ensuring a sustainable energy future.

The study not only sheds light on the technical advancements in solar technology but also holds promise for spurring innovations that can lead to more efficient, adaptable, and sustainable energy practices globally. As researchers continue to explore the possibilities of combining cutting-edge materials and technologies, the future of solar energy looks bright, offering endless opportunities for innovation in the pursuit of clean energy.

Subject of Research: Development of ultra-lightweight flexible perovskite/CIGS tandem solar cells
Article Title: Flexible and lightweight perovskite/Cu(In,Ga)Se2 tandem solar cells
News Publication Date: 19-Mar-2025
Web References: DOI link
References: Joule Journal, March 2025
Image Credits: KOREA INSTITUTE OF ENERGY RESEARCH(KIER)

Keywords

solar energy, perovskite cells, CIGS, renewable energy, efficiency, lightweight technology, advanced materials, energy research, photovoltaic technology.