Growth of the next generation promising Cu2 Fe1-xCoxSnS4 thin films and efficient p-CCTS/n-In2S3/n-SnO2F heterojunction for optoelectronic applications

Abstract

In this paper, we have elaborated Cu2Fe1-x CoxSnS4 (CFCTS) thin films (x = 0%, 25%, 50%, 75% and 100%) by spray pyrolysis technique on glass substrates. The effect of varying (Fe/Co) ratio on chemical composition, morphological, structural, optical and electrical properties has been investigated using energy dispersive X-ray spectrometry (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, spectrophotometer and Hall Effect measurements respectively. XRD results have shown that the change in (Fe/Co) ratio leads to the transformation of stannite CFTS (x = 0%) to stannite CCTS (x = 100%) with the same preferred orientation (112) plan. CFTS and CCTS phases have been confirmed by Raman peaks located respectively at 318 and 325 cm-1. A uniform and dense distribution of CCTS thin film were observed by scanning electron microscopy (SEM). Estimated band gap values of CFTS and CCTS thin films were equal to 1.46 eV and 1.32 eV respectively. Electrical resistivity value was decreased from 5.82 10-3 Ω.cm for CFTS thin film to 5 10-3 Ω.cm for CCTS thin film. These experimental results allow us to consider CFTS and CCTS as good candidates to be used as absorber materials in solar cell devices. Photocatalytic activities of CCTS thin film, CCTS/SnO2:F, CCTS/In2S3 and CCTS/In2S3/SnO2:F heterojunctions have been investigated under sun light irradiation using methylene blue (MB) as representative pollutant dye. It was found that the photodegradation rate was near to 86% in the presence of CCTS /In2S3 / SnO2:F heterojunction after 4 hours which leads to considering it as a good candidate to implement eco-friendly, sun-powered devices for removing organic pollution in waste water. for photocatalysis applications.