This paper reports on the preparation and the characterization of structural, electrical and thermoelectric properties of nanocomposite films formed from three-dimensional networks of polycrystalline bismuth (Bi) nanowires (NWs). The samples were fabricated by electrodeposition within polycarbonate (PC) templates with crossed cylindrical nanopores, yielding self-supported networks of Bi crossed nanowires (CNWs) with mean diameter values ranging from 23 nm to 230 nm. Temperature changes in electrical resistance and thermopower were studied by considering electric and thermal currents flowing in the plane of the films. While the values of the Seebeck coefficient are close to those of polycrystalline Bi for diameters greater than 100 nm, a progressive decrease in thermopower appears at smaller diameters, due to an increasing contribution of surface charge carriers as the diameter decreases. Transverse thermoelectricity based on the Nernst effect was also demonstrated on a network of Bi CNWs 230 nm in diameter. Such hierarchical architectures based on Bi CNWs are extremely robust, offering a reliable solution for the next generation of flexible thermoelectric devices.
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机译:本文报道了由多晶铋(Bi)纳米线(NWs)三维网络形成的纳米复合薄膜的制备和结构、电学和热电性能表征。这些样品通过在具有交叉圆柱形纳米孔的聚碳酸酯 (PC) 模板内进行电沉积制备,产生了平均直径值为 23 nm 至 230 nm 的 Bi 交叉纳米线 (CNW) 的自支撑网络。通过考虑在薄膜平面中流动的电流和热电流来研究电阻和热功率的温度变化。虽然对于直径大于100 nm的塞贝克系数值接近多晶Bi的值,但由于表面电荷载流子的贡献随着直径的减小而增加,因此在较小直径处会出现热功率的逐渐降低。基于能斯特效应的横向热电在直径为230 nm的Bi CNWs网络上也得到了证明。这种基于 Bi CNW 的分层架构非常强大,为下一代柔性热电器件提供了可靠的解决方案。
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