Ligand-Mediated Surface Reaction for Achieving Pure 2D Phase Passivation in High-Efficiency Perovskite Solar Cells
Zhuojie Shi, Shunchang Liu, Ran Luo, Jianpeng Ma, Hao Tian, Xi Wang, Zijing Dong, Xiao Guo, Jinxi Chen, Jiangang Feng, Chuanxiao Xiao, Yuchen Wu, Wenping Hu, Yi Hou
Abstract
The surface passivation with the heterostructure of the 2D/3D stack has been widely used for boosting the efficiency of n-i-p perovskite solar cells (PSCs). However, the disordered quantum well width distribution of 2D perovskites leads to energy landscape inhomogeneity and crystalline instability, which limits the further development of n-i-p PSCs. Here, a versatile approach, ligand-mediated surface passivation, was developed to produce a phase-pure 2D perovskite passivation layer with a homogeneous energy landscape by dual-ligand codeposition. The preferential adsorption of 3,6-dimethyl-carbazole-9-ethylammonium iodide with a large molecular size and lower adsorption energy could regulate the surface reaction between the m -fluorophenylethylammonium iodide and perovskite surface, resulting in a 2D perovskite with a narrow quantum well distribution and a uniform surface potential distribution. Beyond this, the preservation of the surface-confined 2D passivation layer retained a higher electric field at the interface of perovskite and the hole transport layer. As a result, the champion device reached an efficiency of 25.86% for the 0.05 cm 2 device and 25.08% for the 1 cm 2 device, with enhanced operational stability (T 90 > 1000 h) and much better thermal stability. Our work provides deeper insights into efficient and stable 2D passivation for PSCs.