The photoelectrochemical behavior of copper electrode in borax buffer solutions containing benzotriazole (BTA) was studied by using photoelectrochemical techniques. The addition of BTA changes the photoresponse of the electrode from p-type to n-type. In the presence of BTA, both p-type and n-type regions heterogeneously coexist in the Cu2O film on the surface of Cu electrode, and it is shown from IMPS that more positive potential and higher chopping frequency are in favor of appearance of n-type photoresponse.

Key words: BORIC ACID, BORAX, PHOTO-ELECTROCHEMISTRY, BENZOTRIAZOLE