硫化物纳米晶墨水/石墨烯复合对电极的可控构筑及其催化特性

Graphene/transition metal sulfides composites are good counter electrode materials of dye-sensitized solar cells (DSSCs) for their excellent high conductivity, catalytic character and inexpensive cost. But the conventional graphene-based composite counter electrodes are fabricated by doctor-blade method, the graphene could be aggregated easily, and the sulfides could not be well dispersed on the surface of graphene. This will result in the decrease of conductivity and catalytic site. So,the electron transfer and catalytic properties are decreased. The applicant will first controllably synthesize the sulfide nanocrystal ink with different size and species using Schlenk line technique. Then, based on the already prepared graphene counter electrode prepared with electrophoretic deposition method, the well dispersion sulfide nanocrystal ink/graphene composite counter electrodes will be controllably fabricated with spraying coating method. Third, the adsorption energy and electron density of states of the redox shuttle on the surface of sulfide nanocrystal will be systematically calculated using the density functional theory. Final,the cyclic voltammetry and electrochemical impedance spectra (EIS) will be used for systematically investigating the catalytic properties,stability and the interfacial charge transfer resistance of the composite counter electrode-redox shuttle interface. Also, the photoelectron recombination time and diffusion length are investigated in quantitative scale. The regular pattern of the influence of composite counter electrode with different size and species sulfide nanocrystal ink on the DSSC power conversion efficiency will be summarized from the experiment and theory sections. It may explore the new route for the fabrication of counter electrode with inexpensive cost and high catalytic performance.

过渡金属硫化物/石墨烯复合结构因其导电性好、催化性能优异且价格低廉，是很好的染料敏化太阳能电池对电极材料。但通常丝网印刷制备的复合结构对电极,石墨烯容易团聚、硫化物在石墨烯表面不能很好的均匀分散，降低了对电极的导电性和催化点位，从而导致电子传输与催化特性降低。申请者拟采用希莱克技术制备不同尺寸、不同种类的高结晶度的硫化物纳米晶墨水；在前期电泳沉积制备的石墨烯对电极的基础上，利用喷涂包覆的方法可控的构筑均匀分散的硫化物/石墨烯复合对电极。利用密度泛函理论系统的计算氧化还原电对在不同种类纳米晶表面的吸附能和电子态密度；集成运用循环伏安和电化学阻抗详细的研究对电极的催化特性、稳定性及其界面传输电阻、电子寿命和电子扩散距离，从理论和实验两方面归纳总结出不同尺寸、不同种类的硫化物纳米晶/石墨烯复合材料对光电池性能的影响，探索制备廉价、高性能硫化物纳米晶/石墨烯复合对电极的新途径。

染料敏化太阳能电池(DSSCs)因价格便宜、工艺简单、可制成大面积和多形状等优点而成为研究的热点之一。对电极是DSSCs的重要组成部分，通常使用的对电极材料是Pt 纳米粒子，但是Pt是稀有贵金属，难以满足DSSCs大规模生产。石墨化纳米碳及过渡金属 硫化物(或碳化物)材料因其催化性能优异、价格低廉等优点，是Pt的有效替代物质。本项目采用希莱克技术（Schlenk line）实现不同尺寸、不同种类过渡金属硫化物纳米晶墨水的可控制备，通过喷涂包覆的方法可控的构筑均匀分散的金属硫化物纳米晶/石墨烯复合对电极。然后，采用电化学阻抗和循环伏安系统的研究对电极的催化特性、稳定性和光生电荷转移与传输规律，理论和实验相结合，归纳总结出对电极的催化特性及其与电解液的界面电阻、电子寿命等因素对光电效率影响的规律性结果。现在已经达到预订的研究目标，同时在此基础上进一步拓展过渡金属硫化物/磷化物在电催化产氢领域的研究，为此类材料的应用打下了坚实的基础。完成本项目期间，共发表第一标注基金号资助的SCI研究论文12篇，第二标注基金号资助的SCI研究论文1篇，授权发明专利3篇。