Optical, morphological and electrical studies of fully doctor bladed CsPbBr2Cl-based perovskite thin films

Abstract

In the present study, perovskite CsPbBr2Cl and composite CsPbBr2Cl:ZnO thin films were fabricated via low-temperature, solution-processed full doctor blade method, which is a widely used method for producing thin films on large-area surfaces. Surface morphology and crystallinity of the synthesized thin films were investigated by XRD, SEM, and EDX. This study demonstrates that by introducing an appropriate amount of zinc oxide (ZnO) nanoparticles (NPs) into CsPbBr2Cl perovskite precursor solution, more compact, smooth, uniform, pinholes free, thin films with good surface coverage, enhanced crystallization, larger grains, and better optoelectronic properties can be obtained. UV–Visible spectroscopy (UV–Vis) and photoluminescence (PL) measurements were performed to analyze the optical properties of the synthesized thin films. A redshift with a higher absorption range was observed with the incorporation of ZnO NPs into the CsPbBr2Cl precursor solution. The composite system showed a comparatively smaller bandgap with sharp PL emission, which can be attributed to the formation of CsPbBr2Cl:ZnO. The electronic properties of the films were investigated by a Hall-effect setup and it showed the p-type conductivity for the CsPbBr2Cl and composite CsPbBr2Cl:ZnO with a higher carrier concentration of 1.9E*1017 cm−3 and lower mobility of 8.2 cm2V−1s−1 with the incorporation of ZnO NPs. The significant enhancement in photoresponse of CsPbBr2Cl:ZnO thin film makes it a suitable material for optoelectronic applications like perovskite solar cells (PSCs).