Numerical Simulation Approach for High-Efficiency Inverted Perovskite Solar Cells Using Self-Assembled Monolayers

Inverted perovskite solar cells (IPSCs) with p(hole transport)-i(perovskite)-n(electron transport) structures offer several advantages, such as low-temperature fabrication and their applicability in flexible and tandem structures [1]. Despite these benefits, initial studies focused more on n-i-p structures due to the initially low efficiency of p-i-n structures [2]. Recently, self-assembled monolayer (SAM) materials with attractive synthesis cost, low parasitic absorption, tunable energy level, notable defect passivation ability for perovskite have been explored as effective hole transport layer for IPSCs, leading to remarkable efficiency improvements up to 25.4% [3-5]. However, SAMs consist of monolayers or nanometer-scale films, making it difficult to accurately characterize to determine their morphology and electrical properties. This results in an insufficient understanding of their electrical characteristics and limits simulation-based performance enhancements. In this study, we quantified the properties of various SAM materials such as 2PACz, MeO-2PACz, MeO-4PACz, Me-4PACz, 3PATAT-3C, commonly used as hole transport layers in IPSCs using high-resolution surface measurement techniques like Atomic Force Microscopy (AFM) and Ultra-violet Photoelectron Spectroscopy (UPS), X-ray Photoelectron Spectroscopy (XPS). These properties are necessary for the numerical simulation of internal carrier behavior. Then, we calculated the optimal parameters of light absorbing perovskite layers such as layer thickness, composition, and band gap for specific SAM materials by numerical method, a solar cell capacitance simulation-1d (SCAPS-1D). With this numerical simulation, we can select the optimized perovskite layers for each SAM materials to enhance the performance of the IPSC.<br/><br/>[1] Wu, Tianhao, et al. "Self-Assembled Monolayer Hole-Selective Contact for Up-Scalable and Cost-Effective Inverted Perovskite Solar Cells." Advanced Functional Materials (2024): 2316500.<br/>[2] Luo, Xinhui, et al. "Recent Advances of Inverted Perovskite Solar Cells." <i>ACS Energy Letters</i> 9.4 (2024): 1487-1506.<br/>[3] Li, Zhen, et al. "Stabilized hole-selective layer for high-performance inverted pin perovskite solar cells." Science 382.6668 (2023): 284-289.<br/>[4] Liu, Cheng, et al. "Bimolecularly passivated interface enables efficient and stable inverted perovskite solar cells." Science 382.6672 (2023): 810-815.<br/>[5] Zheng, Xiaopeng, et al. "Co-deposition of hole-selective contact and absorber for improving the processability of perovskite solar cells." Nature Energy 8.5 (2023): 462-472.