Chen Weijian, Pham Ngoc Duy, Wang Hongxia, Jia Baohua, Wen Xiaoming
Centre for Translational Atomaterials, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia.
Australian Centre for Advanced Photovoltaics, School of Photovoltaic and Renewable Energy Engineering, University of New South Wales (UNSW), Kensington, New South Wales 2052, Australia.
ACS Appl Mater Interfaces. 2021 Feb 3;13(4):5752-5761. doi: 10.1021/acsami.0c19111. Epub 2021 Jan 20.
A stable and efficient carrier transfer is a prerequisite for high-performance perovskite solar cells. With optimized additives, a significantly improved charge carrier transfer can be achieved at the interface of perovskite/2,2',7,7'-tetrakis-(,-di-4-methoxyphenylamino)-9,90-spirobifluorene (Spiro-OMeTAD) with significantly boosted photostability. Using time-dependent spectroscopic techniques, we investigated charge carrier and mobile-ion dynamics at the perovskite/Spiro-OMeTAD interface, where the Spiro-OMeTAD contains different bis(trifluoromethanesulfonyl)imide (TFSI) salts additives (Li-TFSI, Mg-TFSI, Ca-TFSI). The pristine response and the dynamic changes under continuous illuminations are presented, which is correlated to the different behaviors of mobile-ion accumulations at the perovskite/Spiro interface and ascribed to the improved hole mobilities in Spiro-OMeTAD, ultimately contributing to the favorable behaviors in solar cells. It is demonstrated that the hole mobility and conductivity of hole transport layers play an important role in suppressing mobile-ion accumulation at the interfaces of solar cells. With the engineering of mixed-cation mixed-halide perovskite, optimal engineering of additives in hole transport materials is an efficient strategy. Therefore, it should be emphasized for accelerating perovskite photovoltaic commercialization.
稳定且高效的载流子传输是高性能钙钛矿太阳能电池的前提条件。通过优化添加剂，在钙钛矿/2,2',7,7'-四（-二-4-甲氧基苯基氨基）-9,9'-螺二芴（Spiro-OMeTAD）界面可实现显著改善的电荷载流子传输，同时光稳定性也得到显著提高。利用时间分辨光谱技术，我们研究了钙钛矿/Spiro-OMeTAD界面处的电荷载流子和移动离子动力学，其中Spiro-OMeTAD含有不同的双（三氟甲磺酰）亚胺（TFSI）盐添加剂（Li-TFSI、Mg-TFSI、Ca-TFSI）。给出了原始响应以及连续光照下的动态变化，这与钙钛矿/Spiro界面处移动离子积累的不同行为相关，并归因于Spiro-OMeTAD中空穴迁移率的提高，最终促成了太阳能电池中的良好行为。结果表明，空穴传输层的空穴迁移率和电导率在抑制太阳能电池界面处的移动离子积累方面起着重要作用。通过混合阳离子混合卤化物钙钛矿的工程设计，对空穴传输材料中的添加剂进行优化设计是一种有效的策略。因此，对于加速钙钛矿光伏商业化而言，这一点应予以强调。
