[23a-A306-1~7] 1.4 Energy conversion, storage, resources and environment

▼ [23a-A306-7] Reproducibility and Stability of Pb-free CsBi₃I₁₀ based Perovskite Solar Cells Improved by Bathocuproine Interfacial Layer

〇(D)Md Abdul Karim^1,2, Kiyoto Matsuishi², Towhid H. Chowdhury¹, Wasif Islam Chowdhury³, Muhammad Abdel-shakour^1,2, Ashraful Islam¹ (1.NIMS, 2.Tsukuba Univ., 3.Purdue Univ.)

Keywords:Bismuth, Solar cell, Interface

Bismuth-based perovskite solar cells (Bi-PSCs) have become a suitable alternate as prospective Pb-free PSCs because of their excellent optoelectronic properties but suffer from the lower device performance as reproducibility and stability. The performance limiting factors are crystal defects of perovskite films and interfacial defects at perovskite/electron transport layer (ETL) or perovskite/hole transport layer (HTL). In this research, we focused on the reduction of crystal defects with optimized fabrication conditions, and high reproducibility and stability of Bi-PSCs by interfacial engineering. We introduced a bathocuproine (BCP) interfacial layer (BIL) at perovskite/ETL interface, thus yielding a configuration of ITO/PEDOT: PSS/CsBi₃I₁₀/BCP/C₆₀/BCP/Ag. The inclusion of BIL as a hole leakage blocker at perovskite/ETL interface improved electrical interface contact and significantly improved the PSCs performance. PSCs with 6-nm-sized BIL obtained power conversion efficiency (PCE) of 0.80%, which is significantly higher than control PSCs (0.39%). The addition of BIL improves reproducibility by limiting possible hole leakage from HTL to ETL through the CBI layer. Moreover, PSCs with 6-nm-sized BIL retain ~90% of their initial efficiency even after 528h because of the lower charge accumulation within the PSCs. This study demonstrates the importance of including a BIL at the CBI/ETL interface for fabricating stable and reproducible Bi-based PSCs.