Nanocrystalline FeS thin film used as an anode in photo-electrochemical solar cell and as hydrogen peroxide sensor

Nanocrystalline FeS thin films have been deposited on fluorine doped tin oxide (FTO) coated glass substrates by the thermal decomposition of a precursor complex in aqueous solution. The resulting FeS films were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The optical properties of the deposited films were recorded with the help of UV–vis absorption and photoluminescence spectroscopic measurements. Electrochemical and photoelectrochemical properties were studied using these FeS thin films. A short circuit photocurrent (Isc) of 5.7 mA/cm2, an open circuit photovoltage (Voc) of 0.64 V, a fill factor (FF) of 0.35 and a conversion efficiency (η) of 2.6% were obtained using these FeS films as photo-anodes in a photoelectrochemical (PEC) solar cell under white light illumination of 50 mW/cm2. Repeated illumination cycles showed that the film displayed a reasonable response and photosensitivity. The FeS thin films also showed excellent electrochemical properties towards the reduction of hydrogen peroxide in aqueous solution and could be employed as a H2O2 sensor. The proposed sensor exhibited a good linear response in the range of 0.5–1300 μM with a detection limit of 0.12 μM under optimum conditions.