Wang Yang, Chen Wei, Wang Lei, Tu Bao, Chen Tian, Liu Bin, Yang Kun, Koh Chang Woo, Zhang Xianhe, Sun Huiliang, Chen Guocong, Feng Xiyuan, Woo Han Young, Djurišić Aleksandra B, He Zhubing, Guo Xugang
Department of Materials Science and Engineering, Southern University of Science and Technology (SUSTech), No. 1088, Xueyuan Road, Shenzhen, 518055, Guangdong, China.
Key Laboratory of Functional Polymer Materials and State Key Laboratory of Medicinal Chemical Biology, The Co-Innovation Center of Chemistry and Chemical Engineering of Tianjin, Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China.
Adv Mater. 2019 Aug;31(35):e1902781. doi: 10.1002/adma.201902781. Epub 2019 Jul 11.
Hole-transporting materials (HTMs) play a critical role in realizing efficient and stable perovskite solar cells (PVSCs). Considering their capability of enabling PVSCs with good device reproducibility and long-term stability, high-performance dopant-free small-molecule HTMs (SM-HTMs) are greatly desired. However, such dopant-free SM-HTMs are highly elusive, limiting the current record efficiencies of inverted PVSCs to around 19%. Here, two novel donor-acceptor-type SM-HTMs (MPA-BTI and MPA-BTTI) are devised, which synergistically integrate several design principles for high-performance HTMs, and exhibit comparable optoelectronic properties but distinct molecular configuration and film properties. Consequently, the dopant-free MPA-BTTI-based inverted PVSCs achieve a remarkable efficiency of 21.17% with negligible hysteresis and superior thermal stability and long-term stability under illumination, which breaks the long-time standing bottleneck in the development of dopant-free SM-HTMs for highly efficient inverted PVSCs. Such a breakthrough is attributed to the well-aligned energy levels, appropriate hole mobility, and most importantly, the excellent film morphology of the MPA-BTTI. The results underscore the effectiveness of the design tactics, providing a new avenue for developing high-performance dopant-free SM-HTMs in PVSCs.
空穴传输材料（HTMs）在实现高效稳定的钙钛矿太阳能电池（PVSCs）方面起着关键作用。鉴于其能使PVSCs具有良好的器件重现性和长期稳定性，人们迫切需要高性能的无掺杂小分子HTMs（SM-HTMs）。然而，这种无掺杂的SM-HTMs极难获得，这将倒置型PVSCs的当前记录效率限制在19%左右。在此，设计了两种新型的供体-受体型SM-HTMs（MPA-BTI和MPA-BTTI），它们协同整合了多种用于高性能HTMs的设计原则，并展现出可比的光电特性，但分子构型和薄膜特性不同。因此，基于无掺杂MPA-BTTI的倒置型PVSCs实现了21.17%的显著效率，滞后可忽略不计，且在光照下具有优异的热稳定性和长期稳定性，这打破了高效倒置型PVSCs无掺杂SM-HTMs开发中长期存在的瓶颈。这一突破归因于能级的良好匹配、合适的空穴迁移率，最重要的是MPA-BTTI优异的薄膜形态。这些结果强调了设计策略的有效性，为在PVSCs中开发高性能无掺杂SM-HTMs提供了一条新途径。
