PHOTOELECTRET STUDIES OF PBCRO4-HGO-ZNO COMPOSITES

In the present investigation, we have studied the conditions of maximu m charge storage in PbCrO4-HgO.ZnO photoelectrets. Materials having di fferent compositions are synthesized by heat treatment technique. Meas urements are made with parallel plate capacitors due to ease and econo my of the process, the material. with polystyrene binder between the p lates serving as the dielectric. The dependence of photoelectret charg e (Q(ph)) on synthesizing conditions, charging time, electric held, ra diation intensity, time of dark-depolarization and temperature has bee n evaluated. The Q(ph) versus charging time (t(pp)) curves confirm tha t the photoelectret charge increases with charging time for all sample s having different compositions and maximum charge is retained by 60% PbCrO4-20% HgO-20% ZnO composite. Lower value of photocurrent for 60% PbCrO4-20% HgO-20% ZnO composition confirms the presence of higher den sity of trapping levels in the material in comparison to the 20% PbCrO 4-60% HgO-20% ZnO composition.