Precisely adjusting the organic/electrode interface charge barrier for efficient and stable Ag-based regular perovskite solar cells with >23% efficiency

The hole transport layer (HTL)/anode interface plays an important role in high-performance regular Ag-based perovskite solar cells (PSCs). Usually, the charge barrier caused by the energy level mismatch at the HTL/Ag interface will lead to the abnormal s-type J-V curve, which seriously hindering the commercial application of Ag-based PSCs. Here, we introduce a solution processed molybdenum oxide (HxMoO3) into the HTL/Ag interface to form a double-hole HTL. The work function (WF) of HxMoO3 films can be adjusted by controlling the reaction time. The introduction of HxMoO3 can effectively change the energy-level bending orientation, promote the charge transport and suppresses carrier recombination, thus eliminate the s-type J-V curve. Finally, the Ag-based PSCs achieve a power conversion efficiency (PCE) of 23.16%. Meanwhile, the PCE of the four-terminal (4T) perovskite/silicon tandem cell reaches 26.76%. Furthermore, the HxMoO3 can also be used as a protective layer to prevent the erosion of moisture on the PSCs and the penetration of the silver electrode, improving the stability of the devices. This provides an important reference for the development of perovskites and their tandem solar cells.