Retracted Article: Graphene–SnO2 nanocomposites decorated with quantum tunneling junctions: preparation strategies, microstructures and formation mechanism

Abstract

Tin dioxide (SnO₂) and graphene are versatile materials that are vitally important for creating new functional and smart materials. A facile, simple and efficient ultrasonic-assisted hydrothermal synthesis approach has been developed to prepare graphene–SnO₂ nanocomposites (GSNCs), including three samples with graphene/Sn weight ratios = 1 : 2 (GSNC-2), 1 : 1 (GSNC-1), and graphene oxide/Sn weight ratio = 1 : 1 (GOSNC-1). Low-magnification electron microscopy analysis indicated that graphene was exfoliated and adorned with SnO₂ nanoparticles, which were dispersed uniformly on both the sides of the graphene nanosheets. High-magnification electron microscopy analysis confirmed that the graphene–SnO₂ nanocomposites presented network tunneling frameworks, which were decorated with the SnO₂ quantum tunneling junctions. The size distribution of SnO₂ nanoparticles was estimated to range from 3 to 5.5 nm. Comparing GSNC-2, GSNC-1, and GOSNC-1, GOSNC-1 was found to exhibit a significantly better the homogeneous distribution and a considerably smaller size distribution of SnO₂ nanoparticles, which indicated that it was better to use graphene oxide as a supporting material and SnCl₄·5H₂O as a precursor to synthesize hybrid graphene–SnO₂ nanocomposites. Experimental results suggest that the graphene–SnO₂ nanocomposites with interesting SnO₂ quantum tunneling junctions may be a promising material to facilitate the improvement of the future design of micro/nanodevices.