制备条件对Cu2S光阴极性能的影响

制备了Cu2S纳米材料,研究了制备条件对Cu2S形貌及催化多硫离子还原性能的影响,并将最优条件下制备的Cu2S作为光阴极应用在量子点敏化太阳能电池上.在Cu2S的制作过程中,盐酸对铜片的预处理及铜片和多硫化钠溶液的反应是影响Cu2S性能的两个重要过程.研究结果表明:得到的Cu2S为纳米片组成的花瓣状结构,且随着盐酸浓度的增大和处理时间的延长,表面逐渐变得粗糙和多孔,这有利于增加其表面积,因此Cu2S和多硫电解质之间的界面电荷转移电阻逐渐减小.另外,铜和多硫化钠溶液反应生成Cu2S是一个非常快的过程,反应时间不宜过长,否则Cu2S膜会断裂.在保证Cu2S具有良好催化性能的前提下优化得到的最经济省时的制备条件是:盐酸的浓度为30%,预处理时间为40min,和多硫化钠反应的时间为10s.用此条件下制备的Cu2S作为光阴极组装成量子点敏化太阳能电池达到了4.01%高的光电转化效率.

Influence of Preparation Conditions on the Properties of Cu2S Photocathodes

Cu2S nanomaterials were prepared,and the influence of preparation conditions on the morphology and catalytic reduction of sodium polysulfide was investigated.The Cu2S photocathode prepared under optimal conditions was used as a quantum-dot-sensitized solar cell.For preparation of the Cu2S photocathodes,HCl pretreatment and reaction with sodium polysulfide were important processes. The Cu2S photocathodes had petal-like structures composed of nano-plates.The Cu2S photocathodes become rough and porous,which increased the surface area,as the HCl concentration increased and pretreatment time was prolonged.As a result,interfacial charge transfer resistance between the Cu2S electrodes and polysulfide electrolyte decreased.Because the reaction between Cu and sodium polysulfide is very fast,the reaction time should be controlled.Otherwise,the Cu2S film will fracture.For good catalytic performance of the Cu2S photocathodes,the best preparation conditions were 30%HCl, pretreatment time for 40 min,and reaction with sodium polysulfide for 10s.The quantum-dot-sensitized solar cell showed a high photoelectric conversion efficiency of 4.01%.