Lossless synthesis of graphene nanosheets decorated with tiny cadmium sulfide quantumdots with excellent nonlinear optical properties

Abstract

The implantation and growth of metal nanoparticles on graphene nanosheets (GNS) leads directlyto severe damage to the regular structure of the graphene sheets, which disrupts the extendedπ conjugation, resulting in an impaired device performance. In this paper, we describe afacile approach for achieving the lossless formation of graphene compositedecorated with tiny cadmium sulfide quantum dots (QDs) with excellent nonlinearoptical properties by using benzyl mercaptan (BM) as the interlinker. Themercapto substituent of BM binds to the CdS QDs during their nucleation andgrowth process, and then the phenyl comes into contact with the GNS via theπ–π stacking interaction. Using this strategy, CdS QDs with an average diameter of 3 nm areuniformly dispersed over the surface of graphene, and the resulting QD–graphenecomposite exhibits excellent optical limiting properties, mainly contributed by nonlinearscattering and nonlinear absorption, upon both 532 and 1064 nm excitations, in thenanosecond laser pulse regime.