单线态激子分裂提升Ge-CZTSSe光阴极光解水制氢性能研究

The application of Cu2ZnSnS4（CZTS）semiconductor in photovoltaics and solar water splitting has attracted more and more attention, due to its advantages of low-cost, non-toxic and high efficiency potential. As the developing of technology in recent years, the room for power conversion efficiency improving is becoming less and less. Combining the carrier multiplication process of singlet exciton fission occurred in organic semiconductor with single junction semiconductor is a new promising route to break the Shockley-Queisser limit of single junction semiconductor device, which has advantages of low-cost and high carrier multiplication rate. However, current studies of SF materials focus on its combination with organic photovoltaics and the power conversion efficiency enhancement is trivial. In this project, an efficient Ge-CZTSSe photocathode has a tunable band gap from 1 to 1.9 eV, which is suitable for SF material pentacene (1.9 eV). In theory, this combination has a much higher potential of power conversion efficiency enhancement. The investigation of carrier behavior in the inorganic semiconductor/organic semiconductor/electrolyte interface of pentacene/Ge-CZTSSe hybrid photocathode can offer guidance for the other SF/inorganic semiconductor hybrid structure, which has an important theoretical and application value.

Cu2ZnSnS4（CZTS）是一种低成本、不含有毒元素且理论效率高的半导体光吸收材料，其在光伏和光解水制氢领域的应用受到了广泛关注。随着研究的不断深入，其性能的提升空间在逐渐减小。为了突破SQ极限对单结半导体器件理论转换效率的限制，将有机物半导体中的单线态激子分裂（SF）现象与单节半导体结合，是一种新的潜在方法，且具有低成本、高激子产率的优点。然而，目前的研究主要集中在SF材料与有机半导体光电器件的组合上，且其性能提升并不明显。在本项目中，申请人拟研究的高效Cu2ZnSnxGe1-xSySe4-y (Ge-CZTSSe)光阴极的带隙在1.0-1.9 eV之间连续可调，与SF材料并五苯的带隙1.9 eV匹配，理论上具有高得多的转换效率增益。通过研究光生载流子在无机-有机-电解液界面中的电荷传输过程，能为其他SF材料/无机半导体复合结构的研究提供参考，具有重要理论意义与实际应用价值。

项目主要探索了能够应用于太阳能水分解及二氧化碳还原的新型光电耦合催化材料。阐明了单层二维结构对Cu2ZnSnS4（CZTS）材料的激子效应、能带结构、光催化及电催化分解水性质的影响。发现了体相CZTS材料依赖于不同暴露晶面的电催化还原水产氢及二氧化碳还原的产物选择性。得到了胶体颗粒微结构受动态边界条件调控的非平衡态自组装机制。获得了高效的多孔碳电催化材料。共发表高质量的SCI研究论文4篇，申请专利1项。