Photoluminescence, white light emitting properties and related aspects of ZnOnanoparticles admixed with graphene and GaN

Abstract

ZnO nanoparticles exhibit a broad band centred around 530 nm in the photoluminescence(PL) spectrum due to the presence of oxygen vacancies. Composites of ZnO nanoparticleswith graphenes show marked changes in the PL spectrum with broad bands covering theentire visible region, making them candidates for solid state lighting, while grapheneprepared by arc discharge of graphite in a hydrogen atmosphere (HG) containing 2–3 layersas well as boron-doped (BHG) and nitrogen-doped (NHG) samples of HG give white lightwhen admixed with ZnO nanoparticles; excellent results are obtained with the addition ofjust 7 wt% of BHG to the ZnO nanoparticles. Mixtures of ZnO and GaN nanoparticles alsoexhibit white light emission. The quantum yields of these ZnO nanoparticle based whitelight sources are in the 4–6% range. Photoconductivity characteristics of ZnOnanoparticles are affected by the addition of even a small amount of graphene (<0.5 wt%).