Significant progress has been made in optimizing the processability of tin perovskite absorber layers and enhancing their performance in solar cells. The consortium strategically focused on developing DMSO-free solvent systems, recognizing their potential advantages in efficiency, stability, and reproducibility. While the PCE of these systems currently stands at ~10%, which is a bit lower compared to DMSO-based approaches, their superior reproducibility provides a strong foundation for continued optimization, supporting the path toward the target PCEs above 20% and good operational stability.
Moreover, high-quality tin perovskite thin films have been successfully fabricated through plasma-assisted crystallization, demonstrating reproducible results and tunable grain sizes above 400 nm. Optimization efforts have laid the groundwork for broader implementation, with plasma systems being installed at three project partners to expand this work in the next reporting period. Parallel efforts on device architecture optimization have led to the synthesis of advanced charge transport layers. Notably, we found a novel electron transport layer that exhibited excellent properties, as characterized by time-resolved surface photovoltage measurements, and is currently being integrated into optimized device configurations for further performance evaluation.
Further advancements were achieved in upscaling and module integration. The combination of spray coating and plasma-assisted crystallization showed high potential for roll-to-roll processing, while MorphoColor foils with minimal optical losses (<5%) have been fabricated in several color variations and are currently implemented into tin-based perovskite solar cells. Laser scribing processes in inert atmosphere have been developed and these processes will be capable of achieving geometric fill factors above 95% in modules. Moreover, preliminary steps have been taken for the integration of colored, lightweight, and flexible PV foils into BIPV and IoT applications. Additionally, ecodesign principles have been embedded into process development to mitigate raw material risks and to allow enhanced recyclability.
