Shallow and Deep Trap State Passivation for Low-Temperature Processed Perovskite Solar Cells
Randi Azmi, Naufan Nurrosyid, Sang-Hak Lee, Muhibullah Al Mubarok, Wooseop Lee, Sunbin Hwang, Wenping Yin, Tae Kyu Ahn, Tae‐Wook Kim, Du Yeol Ryu, Young Rag, Sung‐Yeon Jang
Abstract
While perovskite solar cells (PSCs) have emerged as promising low-cost solar power generators, most reported high-performance PSCs employ electron transport layers (ETLs, mainly TiO2) treated at high temperatures (≥450 °C), which may eventually hinder the development of flexible PSCs. Meanwhile, the development of low-temperature processed PSCs (L-PSCs) possessing performance levels comparable to those of high-temperature processed PSCs has actively been reported. In this study, L-PSCs with improved long-term stability and negligible hysteresis were developed through the effective passivation of shallow and deep traps in organic–inorganic hybrid perovskite (OIHP) crystals and at the ETL/OIHP interface. L-PSCs with alkaline chloride modification achieved state-of-the-art performance among reported L-PSCs (power conversion efficiency (PCE) = 22.6%) with a long-term shelf life. The origin of long-term stability and the efficient passivation of deep traps was revealed by monitoring the trap-state distribution. Moreover, the high PCE of a large-area device (21.3%, 1.12 cm2) was also demonstrated, confirming the uniformity of the modification.