Enhancing Photovoltage of Silicon Photoanodes by a High Work-Function Coordination Polymer

A metal–insulator–semiconductor (MIS) structure based on an inhomogeneous junction has been recently proven to be highly efficient at photoelectrochemical (PEC) water oxidation. Engineering the surrounding layer of MIS nanojunction is crucial maximizing photovoltage. Specifically, for n-type photoanode, a high work-function material required create large Schottky barrier that assists hole transfer oxidize while blocking electron transfer. Normally, native oxidized phase metal forms unintentionally. Herein, we demonstrate use copper(I) thiocyanate (CuSCN), transparent p-type coordination polymer semiconductor with work function, specifically surround n-Si/SiOx/Cu nanojunctions, resulting in increased effective height from 0.71 1.03 eV. This phenomenon, known as pinch-off effect, also applied improve performance planar electrode via PEC dissolution method creates surface covered CuOx. The Cu/CuSCN still shows superior characteristics due favorable energetics CuSCN. rational route engineering Si-based photoelectrodes, enabled by facile chemistry polymers.