Feng Jie, Huo Sitao, Jin Xudong, Liu Zirui, Liu Nan, Liang Chaohui, Kong Lingmei, Wang Sheng, Wang Lin, Yang Xuyong
Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, China.
Microelectronics Research & Development Center, School of Mechatronic Engineering and Automation, Shanghai University, 333 Nanchen Road, Shanghai, 200444, China.
Angew Chem Int Ed Engl. 2025 Jul;64(29):e202506179. doi: 10.1002/anie.202506179. Epub 2025 May 20.
Quasi-two-dimensional (quasi-2D) perovskites have shown great potential in the application of light-emitting diodes (LEDs) due to their large exciton binding energy, tunable bandgaps, and solution processability. However, the heavily used spacer cations will cause serious deprotonation reactions in quasi-2D perovskite films, leading to lattice collapse and abundant defect states, which are notorious for fabricating efficient perovskite LEDs (PeLEDs). Herein, we develop an in situ proton-feeding strategy to restrain the deprotonation process in quasi-2D perovskites by introducing a proton-rich Lewis base, namely trifluoromethyl nicotinic acid (TFNA), into the perovskite precursor solutions. The TFNA molecules can donate protons during the growth of quasi-2D perovskite films to simultaneously compensate the deprotonated spacer cations, passivate the defects states by coordinating with Pb, and improve structural stability by forming hydrogen bonds with organic spacers. This leads to an enhanced photoluminescence quantum yield of 78.8%. The resulting red-emitting quasi-2D PeLEDs achieved a high external quantum efficiency of 27.5% at 660 nm, accompanied by a 3.5-fold enhancement of the operational lifetime (T) compared to that of the reference device based on pristine perovskite. This work deepens the understanding of the crystallization of quasi-2D perovskite films and provides a new avenue to improve the PeLEDs performance.
准二维（quasi-2D）钙钛矿由于其大的激子结合能、可调节的带隙和溶液可加工性，在发光二极管（LED）应用中显示出巨大潜力。然而，大量使用的间隔阳离子会在准二维钙钛矿薄膜中引起严重的去质子化反应，导致晶格坍塌和大量缺陷态，这在制造高效钙钛矿发光二极管（PeLEDs）方面是出了名的问题。在此，我们开发了一种原位质子供给策略，通过将富含质子的路易斯碱，即三氟甲基烟酸（TFNA）引入钙钛矿前驱体溶液中，来抑制准二维钙钛矿中的去质子化过程。TFNA分子可以在准二维钙钛矿薄膜生长过程中提供质子，以同时补偿去质子化的间隔阳离子，通过与Pb配位来钝化缺陷态，并通过与有机间隔物形成氢键来提高结构稳定性。这导致光致发光量子产率提高到78.8%。由此得到的发红光的准二维PeLEDs在660nm处实现了27.5%的高外量子效率，与基于原始钙钛矿的参考器件相比，其工作寿命（T）提高了3.5倍。这项工作加深了对准二维钙钛矿薄膜结晶的理解，并为提高PeLEDs性能提供了一条新途径。
