In the present work, a solution-based co-precipitation method has been adopted to synthesize pure and cobalt-doped ZnS quantum dots and characterized by XRD, SEM, TEM with EDX, FTIR and gas sensing properties. XRD analysis has shown a single phase of ZnS quantum dots having a zinc blend structure. TEM and XRD line broadening indicated that the average crystallite size in the sample is in the range of 2 to 5 nm. SEM micrographs show spherical-shaped quantum dots. FTIR studies show that cobalt has been successfully doped into the ZnS cubic lattice. EDX spectra have analyzed the elemental presence in the samples and it is evident that the spectra confirmed the presence of cobalt (Co), zinc (Zn), oxygen (O), and sulphur (S) elements only and no other impurities are observed. The ZnS-based quantum dot sensors reveal high sensitivity towards 50 ppm of ammonia vapors at an operating temperature of 70 °C. Hence, ZnS-based quantum dots can be a promising and quick traceable sensor towards ammonia sensing applications with good response and recovery time.

中文翻译：

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用于追踪低浓度氨的 ZnS 基量子点的合成与表征

在目前的工作中，采用溶液共沉淀法合成了纯和钴掺杂的 ZnS 量子点，并通过 XRD、SEM、TEM 和 EDX、FTIR 和气敏特性进行了表征。XRD分析显示具有锌共混结构的单相ZnS量子点。TEM 和 XRD 线展宽表明样品中的平均微晶尺寸在 2 到 5 nm 范围内。SEM 显微照片显示球形量子点。FTIR 研究表明，钴已成功掺杂到 ZnS 立方晶格中。EDX 光谱分析了样品中的元素存在，很明显，光谱证实仅存在钴 (Co)、锌 (Zn)、氧 (O) 和硫 (S) 元素，没有观察到其他杂质。基于 ZnS 的量子点传感器在 70 °C 的工作温度下对 50 ppm 的氨蒸气具有高灵敏度。因此，基于 ZnS 的量子点可以成为具有良好响应和恢复时间的氨传感应用的有前途且可快速追踪的传感器。