Enhanced thermoelectric properties of p-type polycrystalline SnSe by regulating the anisotropic crystal growth and Sn vacancy

Thermoelectric selenides have attracted more and more attentions recently.Herein,p-type Sn Se polycrystalline bulk materials with good thermoelectric properties are presented.By using the SnSe_2 nanostructures synthesized via a wetchemistry route as the precursor,polycrystalline Sn Se bulk materials were successfully obtained by a combined heattreating process under reducing atmosphere and following spark plasma sintering procedure.As a reference,the Sn Se nanostructures synthesized via a wet-chemistry route were also fabricated into polycrystalline bulk materials through the same process.The thermoelectric properties of the Sn Se polycrystalline transformed from SnSe_2 nanostructures indicate that the increasing of heattreating temperature could effectively decrease the electrical resistivity,whereas the decrease in Seebeck coefficient is nearly invisible.As a result,the maximum power factor is enhanced from 5.06×10~(-4)W/m·K~2to 8.08×10~(-4)W/m·K~2at 612~?C.On the other hand,the reference sample,which was obtained by using Sn Se nanostructures as the precursor,displays very poor power factor of only 1.30×10~(-4)W/m·K~2at 537~?C.The x-ray diffraction(XRD),scanning electron microscope(SEM),x-ray fluorescence(XRF),and Hall effect characterizations suggest that the anisotropic crystal growth and existing Sn vacancy might be responsible for the enhanced electrical transport in the polycrystalline Sn Se prepared by using SnSe_2 precursor.On the other hand,the impact of heat-treating temperature on thermal conductivity is not obvious.Owing to the boosting of power factor,a high z T value of 1.07 at 612~?C is achieved.This study provides a new method to synthesize polycrystalline Sn Se and pave a way to improve the thermoelectric properties of polycrystalline bulk materials with similar layered structure.     

p-型和pn-型染料敏化太阳能电池

针对 (1) p-型染料敏化太阳能电池(DSCs)存在的科学问题, 即光阴极染料的吸附量偏低和电池内部的暗反应比较严重和(2) pn-型DSCs存在的光阳极和光阴极不匹配等问题, 从电极、染料和电解质三个方面系统综述了p-型和pn-型DSCs的研究进展并分析了问题可行的解决方案, 最后对p-型和pn-型DSCs的发展前景进行了展望.     

柔性复合热电材料及器件的研究进展

热电材料能够将热能与电能直接相互转化,在废热回收及绿色制冷领域中具有巨大的应用潜力。相比无机块体热电材料,柔性热电材料具有可弯折、体积小、质量轻等优点,还适用于制备可穿戴电子设备。近10年来,基于导电高分子、碳材料和无机纳米材料等的柔性复合热电材料及器件逐渐成为炙手可热的研究领域,受到了业内广泛的关注。本文综述了近年来基于不同材料体系的柔性热电材料及器件的研究进展、存在的亟待解决的问题和未来的发展方向。大量研究结果表明,材料的热电性能可以通过化学合成和分子设计战略、形貌控制及掺杂技术等进行有效的调控。研发满足实际应用需要的先进柔性热电材料仍然极具挑战性。