Structural and photoelectrochemical characterization of CdS thin film electrodes in photoelectrochemical water splitting system

The structural properties of CdS thin films obtained by ultrasonic spray pyrolysis at different substrate temperature were studied by X-ray diffraction (XRD), scan electron microscope (SEM), Raman spectrum and Uv-vis absorption spectrum. The experimental results show that the crystallinity level gets higher with increasing substrate temperature while the bandgap remains constant. This deposition method should be an effective method as the deposited film looks uniform and smooth in the SEM image. Furthermore, the photoelectrochemical activities of CdS thin films used as electrode to split water to hydrogen and oxygen were investigated. The photoelectrochemical activity increases and then decreases with increasing substrate temperature which forms a peak value at 300 °C . Under a light intensity of 187 mW/cm, the electrode deposited at 300 °C gives a saturated photocurrent of 4.1 mA/cm with increasing electrode potential. The highest energy conversion efficiency was calculated as 0.68% at electrode potential of -0.13 V (vs SCE).