In recent years, perovskite solar cells have emerged as a frontier in photovoltaic technology, captivating the scientific community with their impressive power conversion efficiencies and potential for low-cost, scalable manufacturing. Despite these compelling advantages, a significant challenge has persisted in the form of long-term operational stability, particularly when employing two-dimensional (2D) perovskite interlayers. These 2D interlayers are known to enhance efficiency, but their durability under real-world conditions has consistently fallen short, impeding the commercialization of perovskite-based solar technologies. A groundbreaking study now offers a transformative approach to this problem by reimagining the molecular architecture of the interlayer materials themselves.
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
Tags: 2D perovskite solar cellsAdvanced Photovoltaic Technologybenzoguanamine in perovskite chemistryco-crystal engineering in photovoltaicscommercialization of perovskite solar cellsenhancing solar cell efficiencyinnovative materials for solar energylong-term stability of solar technologieslow-dimensional perovskite interlayersmolecular architecture in solar energy applicationsovercoming ion migration in solar cellssustainable solar power solutions
