  Cu added CdS films were synthesized using spin coating technique at different
spin speeds for different time durations. Films were subsequently annealed at
different temperatures for different time periods in air to crystallize the
phase of CdS in thin film form. Films were characterized using XRD, UV- visible
spectrometer and solar simulator. According to XRD patterns, addition of trace
amount of Cu did not change the structure of CdS. However, the optical band gap
gradually decreases with percentage of Cu as expected. As a result, the
photocurrent, fill factor and efficiency measured in KI/I2 electrolyte
gradually increase with the amount of Cu. Photovoltaic properties could be
improved without altering the structure of CdS. Efficiency enhanced CdS films
find potential applications in solar cell industry.
