Kong Weiguang, Li Wang, Liu Changwen, Liu Hui, Miao Jun, Wang Weijun, Chen Shi, Hu Manman, Li Dedi, Amini Abbas, Yang Shaopeng, Wang Jianbo, Xu Baomin, Cheng Chun
Department of Materials Science and Engineering , Southern University of Science and Technology , Shenzhen , Guangdong Province 518055 , China.
Hebei Key Laboratory of Optic-electronic Information Materials, National-Local Joint Engineering Laboratory of New Energy Photoelectric Devices, College of Physics Science and Technology , Hebei University , Baoding 071002 , China.
ACS Nano. 2019 Feb 26;13(2):1625-1634. doi: 10.1021/acsnano.8b07627. Epub 2019 Jan 25.
High-efficiency hole transport layer free perovskite solar cells (HTL-free PSCs) with economical and simplified device structure can greatly facilitate the commercialization of PSCs. However, eliminating the key HTL in PSCs results usually in a severe efficiency loss and poor carrier transfer due to the energy-level mismatching at the indium tin oxide (ITO)/perovskite interface. In this study, we solve this issue by introducing an organic monomolecular layer (ML) to raise the effective work function of ITO with the assistance of an interface dipole created by Sn-N bonds. The energy-level alignment at the ITO/perovskite interface is optimized with a barrier-free contact, which favors efficient charge transfer and suppressed nonradiative carrier recombination. The HTL-free PSCs based on the ML-modified ITO yield an efficiency of 19.4%, much higher than those of HTL-free PSCs on bare ITO (10.26%), comparable to state-of-the-art PSCs with a HTL. This study provides an in-depth understanding of the mechanism of interfacial energy-level alignment and facilitates the design of advanced interfacial materials for simplified and efficient PSC devices.
具有经济且简化器件结构的高效无空穴传输层钙钛矿太阳能电池（HTL-free PSCs）能够极大地推动钙钛矿太阳能电池的商业化进程。然而，在钙钛矿太阳能电池中去除关键的空穴传输层通常会由于氧化铟锡（ITO）/钙钛矿界面处的能级不匹配而导致严重的效率损失和载流子传输不佳。在本研究中，我们通过引入有机单分子层（ML）来解决这一问题，借助由Sn-N键产生的界面偶极提高ITO的有效功函数。通过无势垒接触优化ITO/钙钛矿界面处的能级排列，这有利于高效的电荷传输并抑制非辐射载流子复合。基于ML修饰ITO的无空穴传输层钙钛矿太阳能电池的效率达到19.4%，远高于基于裸ITO的无空穴传输层钙钛矿太阳能电池（10.26%），与具有空穴传输层的先进钙钛矿太阳能电池相当。本研究深入理解了界面能级排列的机制，并有助于设计用于简化且高效的钙钛矿太阳能电池器件的先进界面材料。
