Despite light-emitting diodes (LEDs) based on quasi-two-dimensional (Q-2D) perovskites being inexpensive and exhibiting high performance, defects still limit the improvement of electroluminescence efficiency and stability by causing nonradiative recombination. Here, an organic molecule, 1-(o-tolyl) biguanide, is used to simultaneously inhibit and passivate defects of Q-2D perovskites via in situ synchronous crystallization. This molecule not only prevents surface bromine vacancies from forming through hydrogen bonding with the bromine of intermediaries but also passivates surface defects through its interaction with uncoordinated Pb. Via combination of defect inhibition and passivation, the trap density of Q-2D perovskite films can be significantly reduced, and the emission efficiency of the film can be improved. Consequently, the corresponding LED shows an external quantum efficiency of 24.3%, and its operational stability has been increased nearly 15 times.

中文翻译：

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前体工程诱导准二维钙钛矿的高效电致发光：一种协同缺陷抑制和钝化方法

尽管基于准二维（Q-2D）钙钛矿的发光二极管（LED）价格低廉且表现出高性能，但缺陷仍然通过引起非辐射复合而限制了电致发光效率和稳定性的提高。在此，有机分子1-(邻甲苯基)双胍被用于通过原位同步结晶同时抑制和钝化Q-2D钙钛矿的缺陷。该分子不仅通过与中间体的溴形成氢键来防止表面溴空位的形成，而且还通过与不配位的Pb的相互作用来钝化表面缺陷。通过缺陷抑制和钝化的结合，可以显着降低Q-2D钙钛矿薄膜的陷阱密度，并提高薄膜的发射效率。因此，相应的LED的外量子效率达到24.3%，工作稳定性提高了近15倍。