金属纳米片阵列/有机半导体光阴极的性能研究及在全分解水光电化学池中的应用

The photoelectrochemical (PEC) cell with tandem configuration can realize the spontaneous solar-driven overall water-splitting, which provides an effective way to deal with the energy crisis and environmental pollution. The key problems for building up a tandem PEC cell are to expand the type and improve the performance of the photocathode. In this project, we construct a new photocathode by utilizing the characteristics of p-type and negative LUMO level of the organic semiconductor. The metal nanosheets array (MNSA) with the advantages of good conductivity, large surface area, good light trapping ability, and adjustable Fermi level is used as the substrate of photocathode to improve the optical absorption, increase the carrier separation, and enhance the contact area. Adjusting the position of the Fermi level through the metal/semiconductor contact will improve the open-circuit photopotential. As a result, the overall PEC performance of photocathode can be improved. By systematically studying the influences of extrinsic properties such as the structural parameters and intrinsic properties such as the band structures on PEC performance, one can deeply understand the carrier transport mechanism and PEC reaction mechanism of the organic-inorganic hybrid system. This project shows great significance on the realization of overall water-splitting reaction without bias and sacrifice agent, understanding of the reaction mechanism, and design of new types of photocatalysts with high efficiency.

串联型光电化学池可实现太阳光驱动下的自发全分解水反应，为应对能源危机和环境污染问题提供了有效的途径。在构建串联型光电化学池的过程中，拓展光阴极的材料种类和提高光阴极的性能，是目前亟待解决的关键问题。本项目利用有机半导体天然的p型特性和LUMO能级电位较负的特点构建新型光阴极，将金属纳米片阵列作为光阴极的衬底，利用金属纳米片阵列导电性好、比表面积大、陷光能力强、费米能级可调节等特点，提高光阴极的光吸收能力、载流子分离能力和光催化反应接触面积，并通过金属/有机半导体接触调节费米能级位置以提高光电压，最终提高光阴极的整体光电催化性能。通过系统研究结构参数等外禀属性及能带结构等内禀属性对光电催化性能的影响，深入理解有机‒无机杂化体系的载流子传输机制和光电化学反应机理。本项目的实施，对实现无偏压、无牺牲剂条件下的光催化全分解水反应、理解光催化反应机理以及设计新型高效光电催化器件等具有重要的意义。

串联型光电化学池可实现太阳光驱动下的自发全分解水反应，为应对能源危机和环境污染问题提供了有效的途径。在构建串联型光电化学池的过程中，拓展光阴极的材料种类和提高光阴极的性能，是目前亟待解决的关键问题。本项目利用有机半导体天然的p型特性和LUMO能级电位较负的特点构建了新型光阴极，将金属纳米片阵列作为光阴极的衬底，利用金属纳米片阵列导电性好、比表面积大、陷光能力强等特点，提高光阴极的光吸收能力、载流子分离能力和光催化反应接触面积，通过金属/有机半导体接触调节费米能级位置以提高光电压，并发展了多种方法提高光阴极稳定性和反应活性，从而提高了光阴极的整体性能；深入研究了有机-无机杂化体系的载流子传输机制、界面相互作用和催化反应机理；最终将光阴极应用于串联型光电化学池，实现了高效、无偏压、无牺牲剂、太阳光驱动的全分解水产氢和产氧。所制备的FTO/Cu NSA/CuI/P3HT:PCBM-TiO2 NRA/IrOx串联型光电化学池，在中性电解液中实现了自发的光电催化全分解水，光电流密度达到110 μA cm2，太阳能-氢能转化效率为0.14%，是引入纳米片前太阳能转化效率的3倍。本项目的实施，对实现自发的光电催化全分解水反应、理解光电催化反应机理以及设计新型高效光电催化器件等具有重要的意义。