Optical Properties of PbS-CdS Multilayers and(CdS+PbS)Thin Films Deposited on Glass Substrate by Spray Pyrolysis

摘要

Two kinds of films containing both PbS and CdS were obtained by spray pyrolysis.The first one,sandwich type,consisting on 2-6 layers,was obtained trough the successive deposition of CdS at 450 deg C,and PbS at 400-425 deg C,from solutions containing either Pb(Ac)_2 or CdCl_2 and thiourea.The second one,mixed(CdS+PbS)was obtained from solutions containing both Cd and Pb salts,having a molar ratio Cd:Pb from 5:1 to 1:5.3,and thiourea,depositing 1-5 layers,at 300-350 deg C.The transmission for sandwich type was of 15.5-23.8% for neutral light,and 20-23% for green light,respectively,as a function of the deposition conditions.For mixed(CdS+PbS)films,the transmission for neutral light was of 6-45%.For all layers the deposition time was 10 s,and the flow rate of the solution 20-25 mL/min.VIS transmission spectra were recorded for the obtained films.The transmission had are intermediate value between these obtained for PbS or CdS films deposited separately.The color parameters in the CIELAB color space have been calculated based on the obtained spectral data.For two of CdS+PbS layers NIR reflection spectra were also recorded.NIR reflection is smaller than the reflection of PbS or CdS deposited separately.The obtained films characteristics depend on the concentration and the molar ratio of cadmium and lead salts and on the number of deposited layers.