Synergistic Interface Modification of Electron-Beam-Evaporated NiO_x for High-Performance Perovskite Solar Cells

Nickel oxide (NiO_x) is considered an ideal hole transport layer (HTL) in inverted perovskite solar cells (PSCs) due to its excellent carrier mobility and low cost. Electron-beam-evaporated NiO_x (E-beam-NiO_x) exhibits exceptional commercial potential due to its process compatibility. However, there are surface defects in E-beam-NiO_x, which are incompatible with perovskite (PVK) and limit its development. In this work, we used [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz) as a self-assembled monolayer (SAM) and l-α-glycerylphosphorylcholine (GPC) to double modify the buried interface of E-beam-NiO_x films. SAM is used to modify interface defects of NiO_x, while GPC improves the wetting property and uniformity of the interface. Under the joint modification of SAM and GPC, the interface defects of NiO_x films were passivated, and the hole extraction ability of HTL was improved. At the same time, the growth quality of PVK films was improved, and the energy level matching between NiO_x and PVK was optimized. After optimization, the small-area (0.0575 cm²) PSCs achieved a champion power conversion efficiency (PCE) of 23.31%, providing an effective strategy and direction for the preparation of high-efficiency PSCs by E-beam-NiO_x.