A comprehensive study aimed to investigate the role of sodium hydroxide precursor concentration on the physical properties of the ZnO nanoparticles. A simple wet chemical approach was employed to synthesize ZnO nanoparticles by keeping the Zn precursor concentration constant and sodium hydroxide concentration varied. XRD analysis confirms the prepared ZnO nanoparticles having a hexagonal wurtzite phase whose crystallite sizes are from 24 to 34 nm. Good crystalline ZnO nanoparticles are realized when the Zn-to-OH precursor concentration is greater than 1:1 molar ratio. UV–Vis spectroscopic studies reveal the optical bandgap of the ZnO nanoparticles can be tailored considerably by varying the alkali hydroxide concentration. The variation in Urbach energy values emphasizes the existence of localized states originating from the lattice disorder and defects. The room temperature photoluminescence analysis confirms the presence of defects in the prepared nanoparticles. Surface morphological investigation of the synthesized nanoparticle samples was investigated using SEM.

中文翻译：

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碱金属氢氧化物浓度对 ZnO 纳米颗粒的结构、光学和表面形态特性的影响

一项综合研究旨在研究氢氧化钠前体浓度对 ZnO 纳米粒子物理性质的影响。通过保持 Zn 前体浓度恒定和氢氧化钠浓度变化，采用简单的湿化学方法合成 ZnO 纳米颗粒。XRD分析证实所制备的ZnO纳米颗粒具有六方纤锌矿相，其微晶尺寸为24至34nm。当 Zn 与 OH 前体的摩尔比大于 1:1 时，可以实现良好的结晶 ZnO 纳米颗粒。紫外-可见光谱研究表明，可以通过改变碱金属氢氧化物浓度来显着调整 ZnO 纳米颗粒的光学带隙。Urbach 能量值的变化强调了源自晶格无序和缺陷的局部状态的存在。室温光致发光分析证实了制备的纳米颗粒中存在缺陷。使用SEM研究合成的纳米颗粒样品的表面形态研究。