Record‐Efficient Flexible Monolithic Perovskite–CIGS Tandem Solar Cell with VOC Exceeding 1.8 V on Polymer Substrate

A surface modification strategy is developed to optimize the interface in flexible perovskite/CIGS tandem solar cells, enhancing charge extraction, reducing nonradiative recombination, and achieving a record efficiency of 22.8% with an open-circuit voltage of 1.82 V.

Abstract

Here, the surface modification of RF sputtering NiOx films by 4PADCB (NiOx-P) is proposed for the first time. The modification effectively suppresses voltage loss at the hole transport layer (HTL)/perovskite interface and optimizes the energy band alignment between the perovskite layer and RF NiOx, thereby enhancing charge extraction and reducing nonradiative recombination of tandem devices, resulting in a flexible monolithic Perovskite (PVK)-CIGS tandem solar cell with the highest efficiency of 22.8% and an extremely high Open-circuit voltage (V_OC) of 1.82 V. This method is expected to obtain better flexible monolithic PVK-CIGS tandem solar cells.