An In-Situ Formed Tunneling Layer Enriches the Options of Anode for Efficient and Stable Regular Perovskite Solar Cells.

Highlights: It is first disclosed that the key to the efficient regular Ag-perovskite solar cells (PSCs) is a tunneling layer (silver iodide, AgI) that is in situ formed by the natural reaction between Ag and the migrated iodide. Based on the discovery, an ultrathin and uniform tunneling layer can be deposited on the fragile perovskite/charge transport layer to enrich the options of electrodes for efficient and stable regular PSCs. Perovskite solar cells (PSCs) are taking steps to commercialization. However, the halogen-reactive anode with high cost becomes a stumbling block. Here, the halogen migration in PSCs is utilized to in situ generate a uniform tunneling layer between the hole transport materials and anodes, which enriches the options of anodes by breaking the Schottky barrier, enabling the regular PSCs with both high efficiency and stability. Specifically, the regular PSC that uses silver iodide as the tunneling layer and copper as the anode obtains a champion power conversion efficiency of 23.24% (certified 22.74%) with an aperture area of 1.04 cm2. The devices are stable, maintaining 98.6% of the initial efficiency after 500 h of operation at the maximum power point with continuous 1 sun illumination. PSCs with different tunneling layers and anodes are fabricated, which confirm the generality of the strategy. [ABSTRACT FROM AUTHOR]