基于自掺杂调控的新型钙钛矿太阳电池的结构设计及性能研究

Perovskite solar cells receive wide attentions, due to the rapid improvement in efficiency. The properties of perovskite films are critical for performance of devices. The self-doping property of perovskite films has significant effect on the property of perovskite films and performance of devices. This project studies the self-doping mechanism of perovskite films, and some novel structures of perovskite solar cells based on the self-doping mechanism have been developed. The mechanism of performance improvement and stability of perovskite solar cells have been studied deeply as well. Furthermore, the flexible design and the way of application are developed in this project. Firstly, the continuous control of self-doping property in perovskite film can be realized by changing the ratio of the perovskite precursor reactant and adjusting the thermal treatment process during the film formation. Secondly, a novel deposition method is developed for fabricating perovskite homojunction. The perovskite solar cells with the novel homojunction structure are designed and constructed after introducing the homojunction into perovskite solar cells. Moreover, the working mechanism of the perovskite homojunction and the influence of homojunction on performance of devices are discovered. The effects of the built-in electric field of perovskite homojunction on the separating and transferring properties of carriers in devices are studied. And we also make the design and optimization of the new structures of perovskite solar cells for enhancing efficiency and stability. Finally, we will develop the flexible application of perovskite solar cells with new structures and expand the application field of photovoltaic devices.

钙钛矿太阳电池由于效率的快速提升获得广泛关注，钙钛矿薄膜的性质是影响电池性能的关键因素，而钙钛矿材料独特的自掺杂特性显著影响薄膜的性质及其器件性能。本项目在深入研究钙钛矿自掺杂调控机制的基础上，设计构建基于自掺杂调控的新型钙钛矿太阳电池结构，研究新型结构钙钛矿太阳电池的增效机理和稳定性，并开拓钙钛矿太阳电池的柔性设计及应用。首先，通过钙钛矿反应前驱物配比以及成膜过程热处理工艺的调控，实现钙钛矿薄膜自掺杂特性的连续可调。其次，开发钙钛矿薄膜同质结结构的制备方法，开展基于同质结的新型钙钛矿太阳电池的结构设计，并探明同质结的工作机制及对电池性能的影响规律；进一步研究同质结内建电场对载流子分离及输运的作用机制，开展新型钙钛矿太阳电池的结构优化设计，实现太阳电池增效和稳定性提升。最后，探索新型钙钛矿太阳电池的柔性应用，拓展光伏器件的应用领域。

钙钛矿太阳电池是一种新型高效的光伏器件，其电池结构和钙钛矿薄膜特性是影响光电转换效率的关键因素。本项目探明了钙钛矿薄膜自掺杂浓度对导电特性的影响机制，并通过控制钙钛矿薄膜前驱体中化学计量比实现了高质量钙钛矿薄膜掺杂浓度的连续调控。基于钙钛矿材料的自掺杂特性，首次设计出钙钛矿同质结结构，并结合溶液法与蒸镀法成膜的各自优势，开发出双沉积工艺，成功实现钙钛矿同质结的构建。进一步将钙钛矿同质结作为光吸收层引入到钙钛矿太阳电池结构中，制备出新型结构的钙钛矿同质结太阳电池，获得了20.80%的光电转换效率，相比于对照的n-i-p异质结钙钛矿太阳电池，效率提升了17.12%。深入研究了电池效率显著提升的原因，证明钙钛矿同质结产生的内建电场可以有效促进光生载流子的定向输运，降低复合损失。基于构建出的钙钛矿同质结，制备出无电荷传输层的钙钛矿同质结太阳电池，获得9.6%的光电转换效率，进一步简化了电池结构的同时也证实了钙钛矿同质结中内建电场对光生载流子的作用。此外，还研究了超薄硅电池的柔性性质，通过在超薄硅表面引入具有纹理结构的PDMS薄膜，实现了超薄硅太阳电池在保证光吸收的同时具有机械柔性特性，为超薄硅-钙钛矿叠层太阳电池的柔性研究积淀了基础。本项目在探明钙钛矿薄膜自掺杂特性基础上，设计构建出钙钛矿同质结及钙钛矿同质结太阳电池，并探明了钙钛矿同质结对电池载流子输运和效率的影响机制，为高效钙钛矿太阳电池的设计与结构创新提供了新思路。