Co-evaporated MAPbI₃ with graded Fermi levels enables highly performing, scalable, and flexible p-i-n perovskite solar cells

• Main Authors: Li, Jia, Dewi, Herlina Arianita, Wang, Hao, Zhao, Jiashang, Tiwari, Nidhi, Yantara, Natalia, Malinauskas, Tadas, Getautis, Vytautas, Savenije, Tom J., Mathews, Nripan, Mhaisalkar, Subodh, Bruno, Annalisa
• Other Authors: School of Materials Science and Engineering
• Format: Article
• Language: English
• Published: 2022
• Subjects: Engineering::Materials; Co-Evaporated Perovskites; Co-Evaporation
• Online Access: https://hdl.handle.net/10356/159675
• Institution: Nanyang Technological University

Recent progress of vapor-deposited perovskite solar cells (PSCs) has proved the feasibility of this deposition method in achieving promising photovoltaic devices. For the first time, it is probed the versatility of the co-evaporation process in creating perovskite layers customizable for different device architectures. A gradient of composition is created within the perovskite films by tuning the background chamber pressure during the growth process. This method leads to co-evaporated MAPbI3 film with graded Fermi levels across the thickness. Here it is proved that this growth process is beneficial for p-i-n PSCs as it can guarantee a favorable energy alignment at the charge selective interfaces. Co-evaporated p-i-n PSCs, with different hole transporting layers, consistently achieve power conversion efficiency (PCE) over 20% with a champion value of 20.6%, one of the highest reported to date. The scaled-up p-i-n PSCs, with active areas of 1 and 1.96 cm2, achieved the record PCEs of 19.1% and 17.2%, respectively, while the flexible PSCs reached a PCE of 19.3%. Unencapsulated PSCs demonstrate remarkable long-term stability, retaining ≈90% of their initial PCE when stored in ambient for 1000 h. These PSCs also preserve over 80% of their initial PCE after 500 h of thermal aging at 85 °C.