Perovskite materials have revolutionized the photovoltaic arena, surging in efficiency and attracting widespread attention for their cost-effective and versatile applications in renewable energy. Traditionally, the highest power conversion efficiencies have been achieved through solution-based deposition of perovskite “inks.” However, such methods face inherent limitations, including challenges in uniform large-area coating and solvent handling. Vacuum deposition, prevalent in producing other thin-film devices like OLED displays, offers a clean, solvent-free, and highly uniform alternative. Yet, all-vacuum-deposited perovskite films have struggled with poor crystallinity, leading to higher defect densities and pronounced instability under operational stresses such as heat and intense illumination.

The HKUST-led research team, under Prof. Lin Yen-Hung in collaboration with the University of Oxford’s Prof. Henry Snaith, tackled this fundamental materials-science challenge. By incorporating a lead chloride (PbCl₂) co-source into their thermal co-evaporation process, they successfully steered the crystallization pathway of the perovskite. This adjustment resulted in an exceptional orientation of wide-bandgap perovskite films (with a bandgap of 1.67 eV), where grains predominantly aligned in the (100) “face-up” configuration—a crystal facet orientation recognized for enhanced photostability and thermal endurance.

The distinct crystal orientation achieved here is not merely aesthetic; it drastically reduces defect states that typically act as traps for charge carriers or sites for degradation reactions. The films’ robust alignment confers resistance against light- and heat-induced damage, significantly extending operational lifetime. These improvements directly translated into superior optoelectronic characteristics, pushing the limits of all-vacuum processed solar cells closer to practical application benchmarks.

Using this proprietary deposition protocol, the research team achieved a certified maximum power point tracking (MPPT) efficiency of 18.35% on a small 0.25 cm² perovskite device—an impressive feat for an all-vacuum-deposited, wide-bandgap solar cell. Laboratory measurements further demonstrated a peak power conversion efficiency of 19.3%, and an 18.5% efficiency was sustained on a more industry-relevant 1 cm² device size, underscoring the scalability and reproducibility of the technique.

Durability testing followed rigorous International Summit on Organic Photovoltaic Stability (ISOS) standards, focusing on the ISOS-L-2 accelerated ageing protocol. The encapsulated perovskite cells maintained 80% of their initial efficiency after 1080 hours under challenging conditions: continuous full-spectrum illumination equivalent to one sun intensity, operated at open circuit, at elevated temperatures of 75 ± 5 °C in ambient air. This stability milestone rivals or exceeds many state-of-the-art solution-processed perovskite devices, highlighting the potential of vacuum-deposited films for long-term reliability in commercial environments.

To unravel the underlying device physics during operation, the team deployed operando hyperspectral imaging—a sophisticated technique developed at HKUST. This method enables spatially and temporally resolved mapping of optical signals within the functional solar cells, revealing microscopic phenomena such as halide segregation and trap-assisted recombination. These insights elucidated the relationship between crystal quality, defect states, and performance degradation, providing a powerful diagnostic framework to hone future device optimization strategies in real time.

Beyond single-junction cells, the research tackles a pivotal industry goal: producing high-efficiency tandem solar cells. Tandems, combining perovskites atop silicon substrates, can surpass the theoretical efficiency limits of individual technologies. Utilizing the finely tuned vacuum deposition approach, the team fabricated perovskite-on-silicon tandem cells with 27.2% efficiency on 1 cm² devices. Critically, these tandem cells displayed promising stability, retaining approximately 80% of their initial efficiency after eight months of outdoor operation in the variable climate of Italy — a significant stride toward commercialization of durable tandem photovoltaics.

This study signifies a paradigm shift in fabricating perovskite solar cells, bridging the gap between laboratory achievements and industrial manufacturing requirements. Prof. Lin underscored that the co-evaporation methodology is fully compatible with existing thin-film deposition infrastructure widely used in semiconductors and display industries. By converting vacuum deposition from a compromised alternative into a front runner for producing high-performance and stable perovskite-based solar devices, the path from research to factory implementation becomes markedly clearer.

The collaborative nature of this breakthrough extended internationally, involving partner institutions such as the University of Oxford, the National Thin-Film Facility for Advanced Functional Materials at Oxford, Eurac Research, and Université Grenoble Alpes in association with France’s Alternative Energies and Atomic Energy Commission (CEA). At HKUST, the research was spearheaded by Prof. Lin’s group within the Department of Electronic and Computer Engineering and the State Key Laboratory of Displays and Opto-Electronics, with key contributions from postdoctoral researcher Dr. Shen Xinyi and senior manager Dr. Fion Yeung.

The implications of this advancement go beyond isolated devices; it represents a crucial step toward integrating vacuum-deposited perovskites into large-scale production lines. The inherent advantages of vacuum deposition—environmental cleanliness, batch uniformity, and process control—combined with the newfound crystal engineering approach, position this technology as a viable contender in the competitive renewable energy market. As the global demand for sustainable, high-efficiency solar energy solutions intensifies, innovations like this may accelerate the transition to cleaner energy infrastructure worldwide.

Ultimately, the demonstration of extended operational stability, high efficiency, and compatibility with silicon tandem architectures manifests a holistic solution that addresses critical bottlenecks in perovskite solar cell commercialization. This refined understanding of crystal facet orientation via multi-source co-evaporation opens new avenues for tailoring thin-film materials to unprecedented performance and durability benchmarks, heralding a new era for perovskite photovoltaics fabricated with industrial scalability in mind.

Subject of Research: Not applicable

Article Title: Crystal-facet-directed all-vacuum-deposited perovskite solar cells

News Publication Date: 23-Feb-2026

Web References:
https://www.nature.com/articles/s41563-026-02494-w
http://dx.doi.org/10.1038/s41563-026-02494-w

Image Credits: HKUST

Keywords

Energy resources

Perovskite solar cells have rapidly climbed to the forefront of photovoltaic research over the past decade due to their remarkable potential for high efficiency and low-cost manufacturing. Despite their promise, these cells historically struggled with issues pertaining to operational stability and longevity, hindering widescale commercialization. The NIMS Award-winning research directly addresses these bottlenecks by introducing a crucial innovation—the solid-state hole transport layer. This component has significantly enhanced both the stability and photoelectric conversion efficiency of perovskite solar cells, marking a transformative step toward their real-world viability.

The integration of the solid-state hole transport layer represents more than a mere incremental improvement; it is a quantum leap in device architecture. By replacing traditional liquid electrolytes, which were prone to degradation and leakage issues, with a solid material layer, the perovskite solar cells now exhibit increased durability under environmental stresses such as moisture and heat. Moreover, this innovation facilitates better charge extraction and transport within the cell, reducing energy losses that previously limited device efficiency.

Technically, the hole transport layer functions by selectively transporting positive charge carriers (holes) from the perovskite absorber to the electrode, ensuring minimal recombination losses while maintaining electrical insulation from the electron-collecting layer. This selective transport is vital because any inefficiency at this interface reduces the overall photocurrent and, subsequently, the power conversion efficiency of the solar cell. The awardees’ contributions effectively stabilized this interface, mitigating hysteresis effects and boosting long-term operational stability—key parameters for real-world application.

What makes this collaborative breakthrough exceptionally noteworthy is its global scale of impact. The independent but synergistic efforts of Miyasaka, Snaith, and Park not only pioneered the application of solid-state hole transport materials but also laid the experimental and theoretical foundations that many research groups worldwide have built upon. Their work bridged the gap between laboratory-scale high efficiencies and scalable, durable devices poised for commercialization.

Beyond the scientific rigor, this achievement aligns seamlessly with the broader imperative of creating sustainable energy technologies. Perovskite solar cells offer a pathway toward affordable, lightweight, and flexible photovoltaics that can be deployed in diverse environments—ranging from urban rooftops to portable electronics. The improved stability fosters confidence among investors and manufacturers, potentially catalyzing mass production models that could accelerate the global transition to clean energy sources.

The NIMS Award ceremony and associated symposium will convene at the Tsukuba International Congress Center on November 11th, 2025. This gathering promises a platform not only for celebrating these remarkable scientific accomplishments but also for fostering dialogue among materials scientists, photovoltaic engineers, and policy makers. The symposium will include detailed lectures given by the awardees themselves, invited talks from leading researchers, and presentations that highlight complementary advancements within the field of energy-related materials.

The international stature of the NIMS Award reflects its stringent selection process, which evaluates groundbreaking contributions from four major subdivisions of materials science: environmental and energy materials, functional materials, structural materials, and basic materials science. Its thematic approach each year ensures that impactful research with real-world applications is prioritized, further emphasizing the role of materials science in addressing pressing technological and societal challenges. For 2025, the spotlight on energy materials underscores the urgent global necessity to innovate sustainable energy technologies.

The recognition of perovskite solar cell innovation by a leading institution like NIMS also highlights the importance of cross-border scientific collaboration. The honorees hail from prominent institutions in Japan, the United Kingdom, and South Korea respectively, underscoring the collaborative nature of contemporary materials science research. Their combined efforts exemplify how diverse academic cultures and expertise can converge to solve some of the most daunting technological problems.

Looking forward, the developments recognized by the NIMS Award will likely stimulate further research into alternative materials and device architectures that enhance photovoltaic performance. This includes exploring new solid-state hole transport materials with better electronic properties, improving perovskite crystallinity and interface engineering, and integrating these cells into tandem configurations for surpassing traditional silicon-based solar cell efficiency limits.

Moreover, from an industrial perspective, the stabilization of perovskite solar cells opens the door for their incorporation into building-integrated photovoltaics (BIPV), wearable electronics, and even aerospace applications, where weight and flexibility are paramount. These applications have the potential to revolutionize how solar energy is harvested and utilized, moving beyond the constraints of traditional rigid panels.

The NIMS Award 2025 thus not only celebrates an exceptional scientific breakthrough but also symbolizes a critical inflection point in the journey toward sustainable energy futures. It honors the dedication and ingenuity of researchers who have translated fundamental materials science insights into transformative technologies. Their work foreshadows a future where clean, efficient, and affordable solar energy is universally accessible, contributing meaningfully to reducing global carbon emissions and combating climate change.

As the world watches the upcoming award symposium, anticipation builds regarding the new research directions and collaborations that this recognition might inspire. The dissemination of knowledge through such prestigious events helps cultivate a vibrant scientific community and accelerates the translation of innovative materials research into solutions that tackle humanity’s greatest challenges.

In summary, the 2025 NIMS Award highlights essential advancements in perovskite solar cell technology, emphasizing the integration of the solid-state hole transport layer. This advancement addresses longstanding issues of stability and efficiency, enabling practical application potentials for perovskite photovoltaics. By honoring Prof. Miyasaka, Prof. Snaith, and Prof. Park, NIMS acknowledges not only their individual excellence but also the enduring global impact of their collaborative scientific achievements.

Subject of Research: Advances in perovskite solar cell technology focusing on stability and efficiency through solid-state hole transport layers.

Article Title: Global Breakthrough in Perovskite Solar Cells Earns NIMS Award 2025 for Pioneering Researchers

News Publication Date: Not specified in the original content.

Image Credits: NIMS (National Institute for Materials Science)

Keywords

Perovskite solar cells, solid-state hole transport layer, photoelectric conversion efficiency, stability, renewable energy, photovoltaic technology, materials science, NIMS Award, sustainable energy, environmental materials, energy materials, solar photovoltaic innovation

At the core of the challenge lies the intrinsic thermal instability of the perovskite light-absorbing layer itself. Unlike traditional crystalline silicon cells, which have proven their durability over decades, perovskite materials exhibit susceptibility to hydrolysis and decomposition when exposed to elevated temperatures and environmental moisture. This chemical vulnerability manifests as a gradual performance degradation, limiting device longevity to a few thousand operational hours under standard test conditions. Such a lifespan pales in comparison to the twenty-plus years of stable operation achievable by silicon photovoltaics, posing a formidable barrier to market acceptance and widespread adoption.

Compounding these material issues is the intricacy involved in scaling laboratory successes to the dimensions required for commercial solar modules. Most experimental perovskite cells are produced at small scales—often just a few square centimeters—that do not meet the industry’s stringent demand for larger, uniform solar panels capable of facile integration into existing infrastructures. Manufacturing these devices at an industrial scale necessitates overcoming sharp constraints related to the perovskite’s remarkably rapid crystallization—from solution casting to functional solid-state film formation, the process window spans mere seconds. This fleeting timing demands pinpoint control over deposition techniques and environmental variables, substantially raising the complexity of reproducible fabrication.

Despite these challenges, perovskite solar cells boast a constellation of remarkable benefits that keep the momentum of their development alight. Their potential for high power conversion efficiency (PCE)—already surging to levels competitive with commercial silicon cells—stands out as a key driver. Furthermore, the low raw material costs combined with simplified manufacturing processes herald the promise of significantly reduced production expenses. The rapid assembly cycle also positions perovskites as attractive options for markets that prioritize swift deployment and flexibility, such as portable electronics, building-integrated photovoltaics, and multi-junction tandem cells.

Excitingly, recent advances in tandem architectures—where perovskite layers are integrated with other photovoltaic materials to capture different portions of the solar spectrum—are poised to elevate efficiencies to unprecedented heights. Professor Wang’s own group has demonstrated flexible monolithic perovskite/Cu(In,Ga)Se2 tandem cells that achieve a certified steady-state PCE of 22.79%, with an even higher laboratory-measured mark of 23.28%. These landmark achievements signal not only the raw potential of perovskite absorbers but also their prospect for incorporation into next-generation, flexible, lightweight solar modules adaptable to diverse applications beyond traditional fixed installations.

The momentum in perovskite research is buoyed by national-level policies committed to accelerating innovation in clean energy technologies. Strategic initiatives such as “The 14th Five-Year Plan for Scientific and Technological Innovation in the Energy Sector,” the “Implementation Plan for Carbon Peak and Carbon Neutrality Supported by Science and Technology (2022-2030),” and the “Guidance on Promoting the Development of Energy Electronics Industry” articulate a roadmap that explicitly encourages the exploration and commercialization of perovskite solar technology. These governmental frameworks provide both funding and regulatory impetus, underscoring the strategic importance of achieving sustainable and efficient photovoltaic solutions in the near future.

The collaborative ethos underpinning this research landscape is evident in the extensive exchanges that Professor Wang’s team maintains with both domestic and international laboratories and industry partners. Such partnerships accelerate knowledge transfer, allowing the refinement of perovskite formulations and manufacturing methods through shared expertise and state-of-the-art characterization tools. By fostering an ecosystem of cooperation, the scientific community moves collectively toward resolving the fundamental limitations impeding the practical deployment of these cells.

A pivotal focus of these efforts zeroes in on improving the stability and extending operational lifetimes of perovskite materials. Research endeavors span the design of novel compositions that resist degradation under heat and humidity, through to innovations in encapsulation strategies that physically shield the active layers from environmental stressors. Addressing these challenges is paramount, as ensuring reliability in real-world outdoor conditions remains a prerequisite for investor confidence and technology adoption at scale.

Simultaneously, honing scalable manufacturing technologies remains critical. Methods such as slot-die coating, blade coating, and vapor deposition are rigorously tested and optimized to control film uniformity, thickness, and crystallinity. The challenge endures to stretch the minute temporal window of crystallization into a more manageable scale compatible with high-throughput roll-to-roll processing, which is essential for cost-effective mass production. These efforts will ultimately determine if perovskite solar cells can transition from the confines of research laboratories into the fabric of global energy infrastructure.

Notably, the exceptional low-light performance of perovskite cells demarcates them from their silicon counterparts, enabling energy harvesting in diffuse lighting conditions such as dawn, dusk, and indoor environments. This versatility extends their usability into new arenas like powering Internet-of-Things (IoT) devices and integrating photovoltaics into building elements that receive indirect sunlight, broadening the impact of solar energy beyond typical sunny landscapes.

The lightweight and potentially flexible nature of perovskite solar cells offer unique design possibilities not afforded by brittle silicon wafers. These attributes accelerate innovation in wearable solar technologies, portable chargers, and even solar-powered vehicles or drones. As form factors shrink and adapt, the paradigm of how and where solar energy is harnessed may undergo a radical transformation—enabling energy autonomy in previously unreachable contexts.

Yet, all these benefits hinge on overcoming persistent obstacles related to material degradation modes. Hydrolysis, ion migration, and phase segregation stand as primary mechanisms that unravel the perovskite’s crystalline integrity over time. Addressing these requires a multifaceted approach, combining material chemistry, interface engineering, and architectural optimization to create robust, multifunctional layers that endure operational stress.

Professor Rui Wang’s research journey vividly exemplifies this crusade against inherent material vulnerabilities. Through meticulous experimentation and strategic partnerships, her group exemplifies how targeted improvements in material formulations and device design can steadily push the envelope of stability without compromising efficiency. This iterative progression marks a hopeful trajectory for perovskite technology, signaling that practical, durable, and scalable solutions are within reach.

Looking ahead, the convergence of scientific innovation, supportive policy ecosystems, and industry engagement raises the prospect that perovskite solar cells will soon transition from experimental novelties to indispensable components of the global renewable energy portfolio. While silicon remains dominant today, the unique combination of cost-effectiveness, adaptability, and emerging performance gains positions perovskite photovoltaics as a formidable contender in the next chapter of the solar revolution.

In sum, the adventure into perovskite solar cell frontiers embodies both the exhilarating promise and sobering realities of innovation at the cutting edge. As researchers like Professor Wang continue to light their way forward with determination and precision, the future of solar energy stands poised for transformative breakthroughs that could redefine our relationship with the sun.

Subject of Research: Perovskite solar cells – their technical challenges, stability issues, scaling, and advancements in efficiency and tandem architectures.

Article Title: Light in heart, forge ahead—Professor Rui Wang’s adventures in perovskite solar cell frontiers.

Article References:
Wang, J. Light in heart, forge ahead—Professor Rui Wang’s adventures in perovskite solar cell frontiers.
Light Sci Appl 14, 176 (2025). https://doi.org/10.1038/s41377-025-01863-5

Image Credits: AI Generated