Cheng Fangwen, He Ruiqin, Nie Siqing, Zhang Chongjian, Yin Jun, Li Jing, Zheng Nanfeng, Wu Binghui
State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, National & Local Joint Engineering Research Center of Preparation Technology of Nanomaterials, College of Chemistry and Chemical Engineering, Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen 361005, China.
J Am Chem Soc. 2021 Apr 21;143(15):5855-5866. doi: 10.1021/jacs.1c00852. Epub 2021 Apr 9.
Perovskite solar cells (PSCs) with organic hole transporting layers (o-HTLs) have been widely studied due to their convenient solution processing, but it remains a big challenge to improve the hole mobilities of commercially available organic hole transporting materials without ion doping while maintaining the stability of PSCs. In this work, we demonstrated that the introduction of perovskite quantum dots (QDs) as interlayers between perovskite layers and dopant-free o-HTLs (P3HT, PTAA, Spiro-OMeTAD) resulted in a significantly enhanced performance of PSCs. The universal role of QDs in improving the efficiency and stability of PSCs was validated, exceeding that of lithium doping. After a deep examination of the mechanism, QD interlayers provided the multifunctional roles as follows: (1) passivating the perovskite surface to reduce the overall amount of trap states; (2) promoting hole extraction from perovskite to dopant-free o-HTLs by forming cascade energy levels; (3) improving hole mobilities of dopant-free o-HTLs by regulating their polymer/molecule orientation. What is more, the thermal/moisture/light stabilities of dopant-free o-HTLs-based PSCs were greatly improved with QD interlayers. Finally, we demonstrated the reliability of the QD interlayers by fabricating large-area solar modules with dopant-free o-HTLs, showing great potential in commercial usage.
具有有机空穴传输层（o-HTL）的钙钛矿太阳能电池（PSC）因其便捷的溶液加工工艺而受到广泛研究，但在不进行离子掺杂的情况下提高市售有机空穴传输材料的空穴迁移率同时保持PSC的稳定性，仍然是一个巨大的挑战。在这项工作中，我们证明了在钙钛矿层和无掺杂剂的o-HTL（P3HT、PTAA、Spiro-OMeTAD）之间引入钙钛矿量子点（QD）作为中间层，可显著提高PSC的性能。量子点在提高PSC效率和稳定性方面的普遍作用得到了验证，超过了锂掺杂的效果。在深入研究其机理后，量子点中间层发挥了以下多功能作用：（1）钝化钙钛矿表面以减少陷阱态的总量；（2）通过形成级联能级促进空穴从钙钛矿向无掺杂剂的o-HTL提取；（3）通过调节其聚合物/分子取向提高无掺杂剂的o-HTL的空穴迁移率。此外，具有量子点中间层的无掺杂剂的o-HTL基PSC的热/湿/光稳定性得到了极大提高。最后，我们通过制造具有无掺杂剂的o-HTL的大面积太阳能模块，证明了量子点中间层的可靠性，显示出在商业应用中的巨大潜力。
