Laser-induced graphene, or LIG, first burst onto the scene in 2014 when researchers at Rice University showed that a commercial CO2 laser could scrib directly onto polyimide film and leave behind a porous, conductive graphene foam. Since then, the technique has become a darling of the flexible electronics community because it requires no catalysts, no chemical precursors, no wet processing and no cleanroom, just a polymer substrate and a laser. Supercapacitors, strain sensors, gas sensors, microfluidic devices and antennas have all been patterned this way. Yet almost all of that progress has relied on infrared CO2 lasers, typically operating around 10.6 micrometers, whose photons are strongly absorbed by the carbon-hydrogen bonds in polyimide and whose power levels often run to tens of watts.

The new study, led by Hedieh Pazokian of the Photonics and Quantum Technologies Research School at the Nuclear Science and Technologies Research Institute in Tehran, together with Reza Ghanbari, Amir Soleimani and Leila Irannezhad, takes a different tack. The team used a compact 445-nanometer diode laser, a device small enough to sit on a benchtop and cheap enough for almost any laboratory, operating at just 1.75 watts. That is a fraction of the power demanded by conventional infrared systems. Building on a parametric study the group had previously published, they scanned the beam across polyimide tape at a writing speed of 10 millimeters per second and a line density of 230 laser pulses per inch, parameters they had already identified as optimal for producing high-quality material with a visible-wavelength source.

The physics behind the conversion is worth pausing on. Polyimide is an aromatic polymer rich in carbon, and when a laser deposits enough heat into its surface, the polymer undergoes photothermal conversion: the imide rings break, non-carbon atoms vent away as gases, and the remaining carbon reorganizes into disordered graphitic layers. A 445-nanometer blue laser interacts with the polymer differently than an infrared one. Visible photons at this wavelength are absorbed less strongly by the polymer backbone, so the process runs at milder effective thermal conditions, and the team suspected this gentler treatment might leave a different chemical fingerprint on the resulting graphene.

To find out, the researchers subjected their material to a battery of characterization techniques. Raman spectroscopy revealed a hierarchically porous graphene network with a moderate defect density, quantified by the ratio of the disorder-induced D peak to the graphitic G peak, which came out at 0.76. That value sits in the range typical of LIG produced by other routes and indicates a carbon lattice that is well graphitized but still contains enough edge sites and defects to be electrochemically interesting. The hierarchical porosity matters because supercapacitor performance depends heavily on ion-accessible surface area: the more pores of the right size, the more electrolyte ions can reach the charge-storing surfaces.

The electrochemical story is where the study becomes genuinely distinctive. Using cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy, the team measured an areal specific capacitance of 34.48 millifarads per square centimeter for a single LIG electrode in a three-electrode configuration. For symmetric solid-state devices, pairing two identical LIG electrodes with a solid electrolyte, the device delivered 9.45 millifarads per square centimeter, a maximum energy density of 1.31 microwatt-hours per square centimeter and a power density of 125 microwatts per square centimeter. Those figures place the 445-nanometer material firmly in the conversation with CO2-derived LIG supercapacitors reported in the literature, despite the dramatically lower laser power involved.

The pivotal discovery came from analyzing the shape of the cyclic voltammograms. If a carbon electrode stores charge purely through the electrical double layer, ions simply accumulate at the electrode-electrolyte interface and the current-voltage curve takes on a near-rectangular, box-like shape. But the blue-laser LIG showed deviations from that ideal rectangular profile, and the analysis of how peak currents scaled with scan rate revealed a measurable pseudocapacitive contribution. Pseudocapacitance arises when charge is stored not just at the surface but through fast, reversible faradaic reactions, typically involving heteroatoms or functional groups on the material. The researchers attribute the effect to oxygen-containing functional groups, carbonyls, hydroxyls and related moieties, that survive the synthesis. In infrared processing, the intense and prolonged heating tends to strip most of these oxygen species from the carbon surface, leaving a nearly pristine, purely capacitive graphene. The milder thermal environment of visible-laser conversion, by contrast, apparently preserves a population of these oxygen groups, which then participate in charge storage alongside the double-layer mechanism.

The team describes this as a mixed-mode charge storage mechanism, and it carries real consequences. Oxygen functionality on carbon electrodes is well known to enhance wettability, improve ion access into the pore network and add extra capacitance through redox-active sites, and the literature on graphene oxide and modified carbons documents how surface chemistry can dominate charge storage behavior. If visible-laser LIG intrinsically retains useful surface chemistry without any post-processing, that removes a fabrication step and opens a route to electrodes whose pseudocapacitive contribution can be tuned simply by adjusting laser parameters.

The practical implications extend beyond electrochemistry. The diode laser used in this work costs a small fraction of a CO2 laser system, draws far less power, and integrates easily into compact, scalable fabrication setups. For applications in wearable electronics, soft sensors, medical patches and Internet of Things devices, where energy storage must bend, flex and conform to the body, the ability to write supercapacitor electrodes directly onto flexible polyimide with an inexpensive blue laser is a genuinely attractive proposition. The authors position visible-wavelength diode lasers as an energy-efficient, accessible and until now underexplored pathway for flexible energy storage fabrication, and their results substantiate that framing with quantitative electrochemical data rather than mere proof-of-concept.

There are, of course, questions still to be answered. The areal capacitance of the single electrode, while respectable, will need to climb for many practical applications, and the team’s own prior work has shown that batch-to-batch variation in LIG electrodes remains a real concern across the field, a problem tied to the sensitivity of laser conversion to power, speed and substrate conditions. Whether the oxygen functionality that drives the pseudocapacitance is stable over thousands of charge-discharge cycles, and whether it survives in gel-electrolyte devices under mechanical strain, will determine how far this mixed-mode storage can be pushed. The researchers also note that the exact balance between double-layer and pseudocapacitive storage can be quantified more rigorously, and the field has recently debated the best analytical frameworks for separating those contributions.

Even so, the study broadens the palette of tools available to the rapidly growing LIG community. It demonstrates that the choice of laser wavelength is not merely a matter of cost and convenience but a genuine chemical lever that changes the surface chemistry and therefore the electrochemical character of the product. A blue diode laser costing a few hundred dollars can now be said to produce not just a cheaper imitation of infrared LIG, but a material with its own distinct storage behavior. For laboratories and startups working on flexible and wearable power sources, that distinction may prove to be the most important part of the story: the cheapest laser on the bench may, in some respects, make the more interesting electrode.

Central to this groundbreaking research is the poly(vinylidene fluoride) or PVDF polymer, a material long prized for its excellent dielectric properties and mechanical flexibility. In this study, however, the researchers push the boundaries by creating an entirely organic composite system, effectively addressing several key challenges that have historically plagued capacitive energy storage materials—namely, limited energy density, mechanical brittleness, and environmental concerns linked to inorganic additives. The engineered structural evolution of the PVDF matrix in this composite optimizes the alignment and interaction of polymer chains, enhancing dielectric permittivity while simultaneously suppressing dielectric loss, a feat rarely achieved in polymer-based capacitors.

Delving into the molecular architecture, the team employed advanced polymer blending and controlled crystallization techniques to manipulate the PVDF morphology at the nanoscale. By precisely tuning the crystallinity and phase distribution within the composite, they were able to facilitate the formation of highly polarized β-phase domains. These domains are crucial as they possess superior dipole alignment that significantly boosts the overall dielectric response of the material. Such structural control is not trivial, requiring a deep understanding of the interplay between kinetic crystallization processes and thermodynamic stability, expertly addressed through an iterative design-and-test methodology.

Beyond the molecular scale, the composite’s macrostructure was engineered to ensure mechanical robustness and flexibility without sacrificing electrical performance. The research team introduced novel all-organic plasticizers and compatibilizers that not only enhance the physical ductility of the composite films but also preserve the dielectric integrity under repeated mechanical stress. This synergistic blend of mechanical and electrical properties promises to open new horizons in flexible energy storage devices, critical for next-generation wearable electronics, foldable displays, and soft robotics.

Experimental results demonstrate that the PVDF-based composite achieves record-high energy density values compared to traditional organic polymer dielectrics, rivaling some inorganic-based systems while maintaining a significantly lower environmental footprint. The composite’s charge-discharge efficiency also exhibited remarkable stability over thousands of cycles, highlighting its potential for sustainable and long-lasting energy storage applications. This performance is particularly impressive given the composite’s all-organic composition, which suggests exciting possibilities for fully biodegradable or recyclable electronics in the near future.

The capacitive energy storage mechanism in this composite fundamentally relies on the maximized polarization within the polymer matrix, achieved by the strategic structural evolution of its components. This polarization effectively increases the stored electrical energy by facilitating efficient charge separation and minimizing leakage currents. Furthermore, the research outlines how this structural approach can be generalized to other polymer systems, creating a versatile platform for customizable energy storage materials tailored to specific application needs.

One of the particularly compelling aspects of this research is the environmental significance it carries. Traditional energy storage materials often incorporate heavy metals or ceramic fillers, leading to environmental disposal challenges and toxicological concerns. The all-organic nature of this PVDF composite addresses these issues head-on, offering a sustainable alternative that aligns with the global push towards green electronics. The researchers envision scalable production methods that could integrate seamlessly into existing polymer processing infrastructure, dramatically lowering the barriers to commercial adoption.

The study also explores the integration potential of the PVDF polymer composite in flexible electronic architectures. Due to its inherent flexibility and high dielectric constant, the composite seamlessly interfaces with flexible substrates without compromising device performance, a crucial requirement for the next wave of portable and wearable technologies. Initial prototyping of flexible capacitors using this composite demonstrates minimal performance degradation under bending, folding, and stretching tests, further validating its applicability in real-world devices.

Innovative characterization techniques played a pivotal role in elucidating the link between structural evolution and electrical properties. The team utilized in situ synchrotron X-ray scattering and advanced electron microscopy to observe crystallization dynamics and phase transitions during the composite formation process. These detailed structural insights enabled the fine-tuning of processing parameters, allowing reproducible fabrication of high-performance materials, a crucial step toward industrial scalability.

The implications of this breakthrough extend beyond capacitive energy storage. Improved understanding of polymer structural evolution and its impact on dielectric properties could influence a broad range of fields, from piezoelectric sensors and actuators to next-generation energy harvesting materials. By demonstrating that tailored all-organic composites can rival inorganic materials’ performance, this research challenges preconceived notions and sets the stage for a paradigm shift in flexible electronics manufacturing.

Remarkably, the team’s approach integrates the principles of green chemistry into advanced materials science, striking a balance between performance, sustainability, and multifunctionality. This holistic perspective addresses not only technical challenges but also broader societal imperatives such as environmental responsibility and resource efficiency. As the electronics industry races towards miniaturization and eco-consciousness, innovations like these will become cornerstones in building the sustainable digital future.

Looking ahead, the research group signals plans to explore hybrid systems that combine these all-organic PVDF composites with emerging two-dimensional materials such as graphene and transition metal dichalcogenides. Such combinations could unlock unprecedented dielectric tunability and multifunctionality, further expanding the scope of flexible energy storage devices. This foresight into material integration highlights the continuous evolution of polymer composites toward increasingly sophisticated device architectures.

Moreover, the researchers underscore the need for multidisciplinary collaborations to accelerate the development and deployment of these advanced capacitive storage materials. By bridging polymer chemistry, materials physics, electrical engineering, and environmental science, the field can rapidly transition from experimental successes to commercial realities. Industry partnerships and pilot manufacturing trials are anticipated to be critical next steps in this roadmap.

In conclusion, the report by Gao, Li, Zhang, and their collaborators marks a milestone in the design and functionalization of all-organic capacitive energy storage systems. Their structural evolution strategy for PVDF-based polymer composites not only enhances dielectric performance but also delivers mechanical flexibility and environmental benefits, embodying the future direction of flexible electronics. As demand for sustainable, high-performance energy storage surges, such innovations will undoubtedly catalyze transformative changes across technology sectors globally.

This research offers an inspiring example of how deep molecular-level understanding paired with innovative materials engineering can lead to disruptive technologies with broad societal impact. The all-organic PVDF composite stands poised to redefine capacitive energy storage’s landscape, fostering advancements that resonate far beyond the laboratories of today into the connected, flexible devices of tomorrow.

Subject of Research: Development and structural engineering of all-organic PVDF-based polymer composites for capacitive energy storage in flexible electronics.

Article Title: All organic PVDF-based polymer composite for capacitive energy storage engineered via structural evolution.

Article References:
Gao, H., Li, C., Zhang, G. et al. All organic PVDF-based polymer composite for capacitive energy storage engineered via structural evolution. npj Flex Electron (2026). https://doi.org/10.1038/s41528-026-00602-z

Image Credits: AI Generated

The core of this innovative technique lies in the utilization of a CO₂ laser to inscribe conductive carbon patterns onto leather in a single, streamlined step. Traditionally, the creation of energy storage devices demands complex chemical treatments and synthetic substrates that pose environmental hazards and severe manufacturing constraints. In contrast, this laser-induced carbonization method leverages the intrinsic properties of vegetable-tanned leather, converting its surface to a porous, conductive carbon matrix that functions as an electrode. The procedure’s adaptability enables precise modulation of laser parameters to fine-tune the electrical characteristics of the carbon layer, eliminating the need for laborious cleanroom conditions or chemical intermediates.

These laser-patterned leather electrodes form the basis of microsupercapacitors capable of rapidly storing and releasing charge, features essential for powering and regulating next-generation wearable electronics. Beyond energy storage, the microsupercapacitors exhibit signal smoothing properties, meaning they can absorb electrical noise and deliver stable power. This dual functionality addresses two critical challenges in wearable device design: reliable power supply and operational stability within flexible, skin-conformal materials.

The practical implications of this research are vast. Flexible microsupercapacitors embedded directly into leather bands, such as those used in smartwatches, could obviate the need for bulky rigid batteries, thereby reducing device thickness and enhancing wearer comfort. The technology also paves the way for integration into smart clothing and epidermal sensors, where continuous, stable energy supply is vital without compromising the softness or breathability of the textile substrate.

This work emerges from a broader investigative pursuit focused on precision laser fabrication of microdevices applied to irregular surfaces. Recognizing the environmental drawbacks of conventional wearable electronics—particularly their reliance on plastics and synthetic chemicals—the research team deliberately chose vegetable-tanned leather for its renewable and skin-friendly qualities. Using plant-based extracts in its processing, this leather serves as an abundant, sustainable platform, highlighting a significant step toward greener electronics manufacturing.

Technically speaking, the laser’s interaction with the leather surface facilitates a pyrolytic transformation, rearranging organic compounds into a carbonaceous, electrically conductive network. The resultant microstructure is not only conductive but also porous, increasing surface area and enhancing the electrochemical performance of the microsupercapacitors. Tests revealed that these devices maintained exceptional operational stability through repeated charging cycles and functioned efficiently at 60 Hz, the frequency standard for AC line filters in electronic circuits.

To vividly demonstrate the versatility of their method, the researchers fashioned microsupercapacitors in intricate shapes including culturally significant motifs such as tigers, dragons, and rabbits. These patterned devices retained full functionality, emphasizing the laser technique’s capacity for high spatial resolution and customizability. This level of design freedom offers exciting possibilities for personalized electronics that combine aesthetics with performance.

Beyond laboratory validation, the team showcased the microsupercapacitors’ ability to power basic electronic components, such as LEDs and wristwatches, under real-world conditions. This practical application underscores the readiness of this technology for integration into consumer products. By merging energy storage and signal filtering in one device fabricated on an organic substrate, the researchers have simplified the supply chain and potentially reduced the ecological footprint of wearable electronics.

Looking forward, efforts are underway to enhance the microsupercapacitors’ performance metrics—optimizing capacitance, energy density, and frequency response—to closely approach the theoretical ideal of capacitive behavior. Durability studies focus on the device’s endurance under mechanical deformation, exposure to sweat and humidity, and prolonged wear, all critical factors for practical deployment. Additionally, ongoing research aims to seamlessly embed these components into broader wearable health-monitoring platforms, envisioning self-powered sensors that do not require external batteries or frequent charging.

This laser fabrication approach not only challenges the status quo of flexible electronics manufacturing but also pioneers a pathway for marrying sustainability with sophisticated device functionality. By utilizing renewable materials combined with precise, chemical-free laser processing, this work exemplifies a paradigm shift toward environmentally responsible, high-performance wearable technology. The anticipated commercialization of such devices could redefine user experience in personal electronics, offering durability, comfort, and ecological mindfulness.

As wearable tech becomes increasingly pervasive and integral to daily life, solutions like these are critical to addressing mounting concerns over electronic waste and resource depletion. The multidisciplinary nature of this research—bridging materials science, photonics, and sustainable engineering—sets a precedent for future innovations aiming to harmonize technology with nature.

Subject of Research: Sustainable fabrication of flexible and wearable microsupercapacitors on natural leather using laser technology for energy storage and signal filtering.

Article Title: Sustainable, wearable planar MSCs for AC line filters and energy storage.

News Publication Date: April 8, 2026.

Web References:

• Optica Publishing Group: https://opg.optica.org/ol/abstract.cfm?doi=10.1364/OL.587978
• Jilin University: https://jilinuniversity.cn/

References:
H. Zhou, T.-T. Zhang, Q. Wang, X.-L. Li, Y.-L. Zhang, D.-D. Han, “Sustainable, wearable planar MSCs for AC line filters and energy storage,” Opt. Lett., 51, 2132-2135 (2025). DOI: 10.1364/OL.587978

Image Credits: Dong-Dong Han, Jilin University

Keywords

Sustainability, Lasers, Sustainable energy, Technology, Flexible electronics, Wearable devices, Microsupercapacitors, Energy storage, Carbonization, Laser fabrication, Organic electronics, Signal filtering