Abstract The facile and fast synthesis of copper sulfide with controllable stoichiometric composition, crystal phase and shape, without using any additional surfactant and structure directing agent, is still highly attractive and remains a challenge. A supercritical methanol synthetic method was presented in this work, by which pure Cu1.8S and Cu9S5/CuS complexes with different particles size and phase composition could be synthesized by tuning the reaction temperature and time. It was demonstrated that higher temperature and longer time were beneficial to the formation of copper sulfides with higher Cu/S ratio and could cause obvious red shifts of band gap energies from 1.34 to 1.54 eV for copper sulfides. Furthermore, crystal phase evolution from Cu9S5 to Cu1.8S was also observed in the preparation process. It was proposed that CuS was produced firstly by decomposing the complex Cu(CN2H4S)2(CH3COO)2, and then reduced to Cu9S5 which was further evolved into Cu1.8S.

中文翻译：

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Cu1.8S和Cu9S5/CuS复合微晶的超临界甲醇合成、相演化及形成机理

摘要 在不使用任何额外的表面活性剂和结构导向剂的情况下，简便快速地合成具有可控化学计量组成、晶相和形状的硫化铜仍然具有很高的吸引力和挑战。本工作提出了一种超临界甲醇合成方法，通过调节反应温度和时间，可以合成不同粒径和相组成的纯Cu1.8S和Cu9S5/CuS配合物。结果表明，较高的温度和较长的时间有利于形成具有较高Cu/S比的硫化铜，并可能导致硫化铜的带隙能量从1.34 eV明显红移至1.54 eV。此外，在制备过程中还观察到了从 Cu9S5 到 Cu1.8S 的晶相演变。