基于CuInS2固态量子点敏化太阳电池的构建及界面载流子动力学的研究

The exploration of new type solar cell is a significant path to achieve the clear reproducible energy. Ternary compound CuInS2 (CIS) has been considered as an ideal light absorption materials, due to its environmentally friendly and earth-abundant sources, and the proper optical band gap well matched to solar spectrum. In this project, as-prepared CIS QDs are firstly sprayed into the mesoporous TiO2 electrode. The electrolyte is introduced by spin coating on the surface of photoanode film, followed by thermally evaporating Au electrode on top finally. Hereby, a structure of solid-state QD-sensitized solar cell can be obtained, which is helpful to simplify the preparation process, lower assembly difficulties, and enhance the long-term stability of solar cells. Reasonable interface modification could suppress the interfacial recombination of photo-induced charge, as well as promote the charge separation and transfer, thus enhancing the power conversion efficiency. The carrier dynamics at the interfaces of solar cells will be also studied by intensity modulated photospectroscopy, the electrochemical impedance spectroscopy and the time-resolved transient absorption spectroscopy, clarifying the key factors which have an effect on the efficiency of devices. In summary, through the optimized design and deep investigation of the solar cells, the project will reveal the mechanism of carrier transportation at the interfaces, providing an effective path to further inhibit the electron recombination and improve photovoltaic performance for solar cell, as well as a new idea to ultimately develop the cell devices with the higher power conversion efficiency.

探究新型太阳电池是实现可再生清洁能源的重要途径之一。三元化合物CuInS2（CIS）由于原材料环境友好且来源丰富，并具有与太阳光谱非常匹配的光学带隙，是一种理想的光吸收材料。本项目首先将制备好的CIS量子点喷涂在多孔TiO2电极上，再将电解质旋涂在光阳极薄膜上，最后在顶层蒸镀Au电极，从而得到一种全新的固态量子点敏化太阳电池结构。此结构简化了电池制备过程，降低了电池组装难度，提高了电池长期稳定性。利用合理的界面修饰抑制光生电荷的界面复合，促进电荷的分离和转移，以此提高电池的能量转换效率。通过强度调制谱、电化学阻抗谱和时间分辨瞬态吸收光谱测量技术研究电池界面处的载流子动力学行为，澄清影响器件效率的关键因素。总之，该项目将通过对太阳电池的优化设计和深入考察，揭示电池界面处载流子的传输机制，为进一步抑制电子复合、改善电池光伏性能提供有效途径，为最终研制出具有较高能量转化效率的电池器件提供新思路。

本项目将三元化合物CuInS2（CIS）作为量子点太阳能电池的光吸收材料，将其喷涂在多孔TiO2电极上，再将电解质旋涂在光阳极薄膜上，最后在顶层热蒸镀Au电极，从而得到一种全新的固态量子点敏化太阳电池结构。此结构简化了电池制备过程，降低了电池组装难度，提高了电池长期稳定性。研究表明合理的界面修饰可以抑制光生电荷的界面复合，促进电荷的分离和转移，提高电池的能量转换效率。取得的主要研究结果如下：.1. 采用热注入法合成出晶粒大小适中、表面缺陷少、结晶度高的CIS量子点，并对其进行了表面配体交换，再将CIS量子点非原位吸附在TiO2多孔膜中。通过调节工艺参数，CIS量子点在TiO2表面达到了适宜的吸附量和覆盖率，形成了较好的 TiO2/CIS 光电极吸光率。.2. 在TiO2/CIS光阳极薄膜上旋涂一层spiro-OMeTAD 有机电解质后在顶层蒸镀Au 电极，构建出新型高效、低成本、安全环保、宽光谱响应的固态QDSSCs器件原型。进一步优化CIS量子点敏化TiO2光阳极的吸光性能，改善电子的注入效率，达到提高太阳能电池能量转化效率的目的。.3. 利用离子掺杂或退火处理修饰界面，有效抑制了光生电荷的界面复合，促进了载流子在TiO2/CIS光阳极界面处转移运输。适宜的界面修饰使得电荷载流子具有较长寿命，这有利于改善电荷收集效率，从而显著提高了IPCE和Jsc。