Photoelectrochemical (PEC) characterization of chemically deposited Bi2S3 thin films from non-aqueous medium

Bi2S3 thin films have been prepared by chemical bath deposition method usin g bismuth nitrate, Bi(NO3) and sodium thiosulphate (Na2S2O3) dissolved in a cetic acid and formaldehyde respectively. Films were deposited onto flourin e doped tin oxide coated (FTO) glass substrates. The photoelectrochemical ( PEC) cell configuration was n-Bi2S3/0.25 M NaOH-0.25 M Na2S-0.25 M S/C. Fro m the current-voltage characteristics (I-V) and capacitance-voltage (C-V) p lots, it is concluded that the Bi2S3 films are of n-type conductivity. The photovoltaic output characteristics were used to calculate fill factor (FF) and solar conversion efficiency (eta). The low value of eta may be due to high value of series resistance and interface states in the cell which are responsible for the recombination mechanism. The magnitude of band gap ener gy of Bi2S3 photoelectrode estimated from spectral response of PEC cell agr ees with the magnitude obtained from optical absorption of Bi2S3 films. The magnitude of decay constant estimated from transient photoresponse indicat ed the charge transfer kinetics is of second order. (C) 1999 Elsevier Scien ce S.A. All rights reserved.