Aqueous preparation of surfactant-free copper selenide nanowires

•Surfactant-free copper selenide nanowires prepared by aqueous route.•Nanowires induced by assembling of nanoplates, accompanied by self-redox reaction.•High electrical conductivity, small Seebeck coefficient and low thermal conductivity.•A comparable figure of merit with commercial sample.

Uniform surfactant-free copper selenide (Cu2−xSe) nanowires were prepared via an aqueous route. The effects of reaction parameters such as Cu/Se precursor ratio, Se/NaOH ratio, and reaction time on the formation of nanowires were comprehensively investigated. The results show that Cu2−xSe nanowires were formed through the assembling of CuSe nanoplates, accompanied by their self-redox reactions. The resultant Cu2−xSe nanowires were explored as a potential thermoelectric candidate in comparison with commercial copper selenide powder. Both synthetic and commercial samples have a similar performance and their figures of merit are 0.29 and 0.38 at 750 K, respectively.

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