p-CuSCN (band gap=3.1eV) Sensitized Cu2O Quantum Dots (QDs) Photoelectrochemical Cell

Abstract

This work focuses on making photoelectrochemical cell for the first time by sensitizing p-CuSCN with Cu2O quantum dots (QDs). Copper (I) thiocyanate (CuSCN) is wide band gap material which is sensitive only to UV light. This wide band gap semiconductor can be made sensitive to visible light by sensitization with quantum dots. Cu2O QDs were prepared on Cu/p-CuSCN photoelecrode by boiling Cu/pCuSCN in a 1M CuSO4 solution. Boiling time controlled the size of the quantum dots. It was found that the boiling time below 20min, QDs of Cu2O can be fabricated on pCuSCN and for longer period of boiling above 20min Cu2O micro crystals were fabricated on p-CuSCN forming a pCuSCN/n-Cu2O junction photoelectrode. Higher photocurrents were shown from the QD sensitized photoelectrochemical cells with compared to that of the Cu/p-CuSCN/n-Cu2O junction photoelectrochemical cells. Photocurrent measurements and diffuse reflectance spectra were presented to explain the mechanism of photocurrent enhancement for the p-CuSCN sensitized QDs of Cu2O.