Water splitting by electrodeposited cuprous oxide photoelectrodes with a flower like morphology

Abstract

Morphology of semiconductor films plays a major role in determining the efficiency of solar cell devices. Intrinsic electronic properties of cuprous oxide (Cu2O) are important for water splitting reaction using solar energy to produce environmentally clean hydrogen fuel. Especially, the n-type cuprous oxide thin films with flower-like morphology have an added advantage for efficient water splitting. In this study electrodeposition of Cu2O thin films using an aqueous H2O2 bath was investigated for the possibility of depositing films on Ti substrates with a flower-like morphology. Direct deposition of Cu2O films on a Ti substrate using a H2O2 bath is not possible. However, it was found that if a thin Cu2O film was deposited using an acetate bath prior to the film deposition, good films with a flower-like morphology can be electrodeposited. In this study, Cu2O thin films were deposited on Ti substrates in a bath containing 0.1M CuSO4 and 0.3M H2O2 at 600C. pH value of the bath was kept at 4 by adding few drops of dilute NaOH solution. SEM pictures show the flower ?like morphology of the films. V-I characteristics and the spectral responses confirmed the n-type behavior of the deposited films. Possibility of water splitting using n-type Cu2O films without applying an external bias is demonstrated in this study. The performance of the films in a photoelectrolytic solar cell with a flower like morphology is compared with the films with normal morphology.