Copper-copper iodide hybrid nanostructure as hole transport material for efficient and stable inverted perovskite solar cells

A CuI coated Cu hybrid nanostructure by partial iodation of Cu nanowires was used as hole transport material (HTM) to enhance the charge transfer in inverted perovskite solar cells (PSCs). The outer CuI achieved efficient charge extraction, and the inner copper facilitated the extracted charges to be rapidly transferred, further improving the overall cell performance. Furthermore, we employed a mixture of [6,6]-phenyl-C71-butyric acid methyl ester (PCBM) and ZnO nanoparticles as electron transport material (ETM) to achieve the fabrication of stable PSCs. The best efficiency was up to 18.8%. This work represents a fundamental clue for the design of efficient and stable PSCs using the chemical in-situ construction strategy for HTM and integration of PCBM and ZnO as ETM.