Porous ZnO Sheets Transformed from Zinc Sulfate Hydroxide Hydrate and Their Photoluminescence Performance

Abstract

Highly crystalline, porous ZnO sheets were prepared from chemically-deposited zinc sulfate hydroxide hydrate (ZSH) sheets by sintering at 1000°C. The formation mechanism of ZSH in Zn 2 +hexamethyltetramine (HMT) precursor system, the transformation process of ZSH to ZnO, and the crystalline, microstructural and optical properties of the ZnO sheets were investigated. The porous ZnO sheets possessed a well-defined hexagonal shape with controllable size (10-50 μm) and thickness (200-500 nm), high crystallinity, and strong ultraviolet photoluminescence without detectable defectrelated visible emission. Submicron-sized pores (100-500 nm) and polygonal or irregular ZnO particles resulting from the limited mass transport during high temperature sintering were observed in the ZnO sheets. Analysis of the formation mechanism indicated that the high affinity of SO 2-4 for Zn 2+ was responsible for the formation of ZSH in the Zn 2 + -HMT precursor system, and the thermolysis of ZSH affected the morphology and microstructure of the ZnO sheets. This work reveals a facile route to porous ZnO nanostructures with good crystallinity and optical properties, which make them suitable for application in catalysis, and photo and/or electrical devices.

ÇİNKO HİDROKSİ SÜLFAT (Zn4SO4(OH)6)’IN ÜÇ FARKLI BAZİK ORTAMDA SENTEZİ, KARAKTERİZASYONU VE TERMAL BOZUNMASI

“…NaOH ve boraks ortamlarında çinko hidroksit sülfat (Zn4(OH)6SO4‧nH2O)'ın sentezi oda sıcaklığında (25°C) yapıldı. Fakat HMT ortamında 25°C'de çökme gözlenmediğinden bu konuda yapılan literatür (Peng et al, 2013) temel alınarak sentezlenme işlemi 80°C'de yapıldı. Yapılan deneylerde, üç ayrı behere 50 mL 0.1M ZnSO4.7H2O konuldu.…”

“…İlk olarak, HMT, amino gruplarının hidrolizi yoluyla OH oluşumunu teşvik etmektedir. İkincisi ve en önemlisi, HMT, etilendiamin gibi katmanlı çinko hidroksit sülfatta sütun görevi yapmaktadır (Staminirova, Petrova and Kirov, 2016;Peng et al, 2013).…”