Perovskite thin-film working as a charge communicator with CdS/CuS heterostructure thin film for optoelectronic applications

In this work, the cadmium sulfide (CdS)/Perovskite/copper sulfide (CuS) film layers were fabricated via a chemical bath deposition, spin coating, and doctor blade methods. As-synthesized thin films are studied through standard characterization techniques such as X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) with EDAX, atomic force microscopy (AFM), and UV–visible spectroscopy. Structural properties were analyzed through XRD and Raman. The resulting optical energy bandgaps for CdS, perovskite, and CuS are 2.4 eV, 1.65 eV, and 2.3 eV, respectively. The morphological images of the samples are obtained from the SEM confirming their structures and from EDAX the elemental composition is verified. The measured surface roughness showed the increment as the layer-by-layer CdS/Perovskite/CuS structure fabricated, which somehow contributed to the enhancement of optoelectronic properties. The electrical and application-based properties were investigated through I-V characterization. The CdS/CuS bi-layer structure has been modified via the insertion of as-synthesized perovskite material. Moreover, the insertion of the perovskite layer between them has improved the photosensing performance. The improvement in the solar sensing performance is due to the perovskite properties such as rich charge carriers, narrow bandgap, and good conductivity, which makes it a good charge communicator in the CdS/CuS low-cost thin-film photosensor.