Surface dipole affords high-performance carbon-based CsPbI2Br perovskite solar cells

All-inorganic carbon-based perovskite solar cells (C-PSCs) are an effective substitute for traditional organic–inorganic PSCs due to their excellent heat tolerance. However, the energy level mismatch between the inorganic perovskite and the carbon electrode leads to serious undesired charge recombination, which reduces photovoltaic performance of the devices. Here, we introduced 4-aminotetrahydropyran bromide (ATHPBr) as an electric dipole molecule to adjust the electronic state of the interface to cause a change in the work function (WF) and improve the extraction and collection of holes between the CsPbI2Br and the carbon electrode. The efficiency of the modified device increases from 12.78% to 14.50%, which is currently one of the highest reported efficiencies of all-inorganic C-PSCs. The device maintains 94% of the initial efficiency after 1200 h aging under a 15–20% relative humidity (RH) ambient condition at room temperature. Therefore, it is a novel and effective way for preparing highly efficient and stable all-inorganic C-PSCs.