Effect of Higher Carrier Mobility of the Reduced Graphene Oxide–Zinc Telluride Nanocomposite on Efficient Charge Transfer Facility and the Photodecomposition of Rhodamine B

Abstract

The synthesis of solar-light-responsive zinc telluride (ZnTe) nanoparticles and their composite with reduced graphene oxide (rGO–ZnTe) via a simple hydrothermal reaction is reported. The synthesized nanostructures were comprehensively characterized by a combination of X-ray diffraction and photoelectron spectroscopy, electron microscopy, UV–vis spectroscopy, photoluminescence spectroscopy and thermogravimetric analysis. The effects of graphene oxide on the crystallinity, microstructure, photo-excitation, light absorption, surface area and thermal stability of ZnTe were studied. The current–voltage (I–V) characteristics for both as-synthesized ZnTe and rGO–ZnTe composite-based Schottky devices were measured to estimate the charge transport parameters such as dc conductivity, photosensitivity, carrier’s mobility and lifetime. The photocatalytic performance of both the materials in the degradation of an azo dye (Rhodamine B) was subsequently investigated using simulated solar light. The rGO–ZnTe composite exhibited a higher photocatalytic activity (66%) as compared to the as-synthesized ZnTe (23%), essentially due to the synergy between rGO sheets and ZnTe nanoparticles. The role of the carrier’s mobility in the transportation of photo-induced charges (electrons and holes) through the complex network of the composite materials and thus facilitating the photo-degradation process is explained. In the end, the responsible reactive species for the decomposition of Rhodamine B was also interpreted.