摘要:
利用水热合成技术,分别以CuCl2·2H2O,硫粉为铜源和硫源,以KOH或NaOH为矿化剂,成功合成了Cu2S纳米晶体和碱金属离子掺杂的KCu7S4纳米线和NaCu5S3微纳米球.通过X射线衍射(XRD)、电子能谱(EDS)、扫描电镜(SEM)、透射电镜(TEM)和高分辨率透射电镜(HRTEM)对产物的结构和形貌进行了表征和分析.结果显示：KOH含量低于1g或NaOH低于2 g时,产物为斜方辉铜矿Cu2S；高碱含量(不低于3 g)时, K或Na离子成功掺入产物结构中, K掺杂产物为纯净的四方相KCu7S4,单晶结构,尺寸均匀,长度可达几十微米的纳米线；Na掺杂未改变产物的形貌,形成六方晶系结构的NaCu5 S3.产物的形成和生长与反应温度、反应时间和矿化剂密切相关.并讨论了Cu2 S纳米晶及其掺杂纳米晶的形成机理及掺杂机理.最后研究了碱金属离子掺杂对产物的光学性能的影响,漫反射光谱显示Cu2S, KCu7S4和NaCu5S3纳米晶的光学带隙分别为1.21 eV,0.49 eV和0.42 eV, K+和Na+的掺杂,极大的改变了产物的光学特性.
Abstract:
Cuprous sulfide (Cu2S) nanocrystals and K or Na doped KCu7S4 nanowires and NaCu5S3 micro-nanospheres have been synthe-sized successfully by using a simple hydrothermal method, using KOH or NaOH as mineralizing agent, CuCl2·2 H2O and S powders as copper and Sulfur sources, respectively. The structure and morphology are characterized and analyzed by X-ray diffraction (XRD), energy dispersive X-ray spectrum (EDS), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The results reveal that under conditions that the amount of KOH is below 1g or the amount of NaOH below 2 g, the product is of the orthorhombic chalcocite Cu2S, while with high alkali amount (no less than 3 g), K+ or Na+ is successfully incorporated into the Cu-S structure;KCu7S4 has the pure tetragonal single crystal structure, and its uniform nanowires can be up to several tens of micrometers in length. Na doping has no effect on the morphology of the product, which forms the hexagonal NaCu5S3. The formation and growth of the product are closely related to the reaction temperature, reaction time and mineralizing agent. And, the formation and doping mechanisms are discussed. Finally, the influence of the alkali metal ion doping on the optical properties of the product is investigated. The diffuse reflectance spectra demonstrate that the optical band gaps of Cu2S, NaCu5S3 and KCu7S4 nanocrystallines is 1.21, 0.49, 0.42 eV, respectively. And K+or Na+doping greatly affects the optical characteristics.
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