Enhanced performance of inverted perovskite solar cells using solution-processed carboxylic potassium salt as cathode buffer layer

Abstract

Using a novel solution-processed carboxylic potassium salt (F-R-COOK) as cathode buffer layer (CBL), a power conversion efficiency (PCE) of 14.37% is obtained, which is more than 51% increase compared with that of the Ag-only device under similar fabrication conditions. The test result of single electron devices and Electrochemical impedance spectroscopy (EIS) measurements demonstrate that the interlayer decreases charge transport resistance. Ultraviolet photoelectron spectroscopy (UPS) measurements are used to study the interfacial effects induced by the new CBL. It is found that F-R-COOK can reduce the work function of the Ag electrode by forming desired interfacial dipoles. Our work indicates the promising applications of F-R-COOK based CBL in perovskite solar cells and may provide some insights into the design and synthesis of new interfacial materials to further improve the device performance.