Pure, Size Tunable ZnO Nanocrystals Assembled into Large Area PMMA Layer as Efficient Catalyst

Abstract

Here, we demonstrate for the first time a strategy to self-assemble ZnO nanoparticles (NP) on a large area by a facile one-step process. First, rough and random ZnO nanocrystals (NC), were produced by free-stabilizing aqueous synthesis. Therefore, a post thermal treatment at various temperatures ranging from 80 to 800 °C was necessary to obtain size-tunable and photoluminescent crystalline NP. The fabricated NP had both efficient UV photoluminescence and photocatalytic activity by photo-degradation of Methylene Blue (MB) dye. The annealed NP showed an absorption blue shift in the UV region with decreasing size. This shift was attributed to high quantum confinement effect since ZnO NP diameter reached values lower than the Bohr radius of ZnO (~2.7 nm). The photocatalytic activity displayed dependency on the particle’s size, number, and crystallinity. Subsequently, the NP were self-assembled inside poly(methyl methacrylate) (PMMA) nanoholes. Subsequently, large area substrate of homogenous properties ZnO NP was obtained. Moreover, the synthesis facility, photoemission and photocatalytic properties of ZnO NP could be a new insight into the realization of high performance and low cost UV laser devices.

Plasmon‐Enhanced Photoluminescence and Photocatalysis Reactions in Metal‐Semiconductor Nanomaterials: UV‐Generated Hot Electron in Gold‐Zinc Oxide

“…Figure (c) represents the UV‐Vis extinction spectrum and an expanded portion showing the UV region of the PL spectrum of the selected water dispersion of ZnONPs. These results were recently obtained and reported by our group …”

“… ZnONPs used for coupling with AuNPs; (a) TEM image, (b) SEM‐FEG image, (c) extinction spectrum and (d) photoluminescence spectrum of the corresponding ZnO. The insert in (d) is the image of the ZnO dispersion under UV light …”

“…The latter peak is referred to the radiative recombination of the near band edge (NBE) emission of the exciton. The broad band in the visible region ranging from 500 nm to 900 nm corresponds to the defects luminescence …”

“…To make it possible, we measured the ability of the ZnONPs before and after coupling with AuNPs to degrade methylene blue (MB) dye, under UV light irradiation. The photocatalytic (PC) process was well described previously in our previous reports, and the charge transfer between ZnO and AuNPs was assessed before. The charge transfer and PC activity is illustrated in Scheme .…”

“…A previously reported approach is used to synthesize ZnO nanoparticles by our group . The ZnONPs were synthesized in an aqueous medium by simple heating at 80 °C for 20 min, then the obtained products were annealed after filtration in an oven at 250 °C for 1 hour.…”