Abstract In this study, we demonstrate a simple method to achieve highly efficient perovskite light-emitting diode (PeLED) via casting the neat methylammonium bromide (MABr) in mixed solvents with different solubility on top of the perovskite layer for bulk recrystallization and interfacial passivation. The perovskite crystals reacting with MABr can be reformed orderly and stereoscopically with a reduced domain size on surface and reduced grain boundaries in bulk, which is advantageous to obtain strong fluorescence intensity and long exciton lifetime. The remaining MABr molecule that does not react with perovskite can attach on the recrystallized perovskite surface to develop a passivation layer, which can effectively eliminate exciton interface recombination in PeLEDs. The optimized PeLED exhibits a maximum luminance of 27692.2 cd m−2, which is more than 11 times and 2 times higher than the control device without MABr treatment and the control device with high MABr molar ratio and thin perovskite film thickness, respectively. This work provides an effective strategy to boost PeLED performance by optimizing mixed solvent ratios and concentrations of organic ligand MABr without changing the thickness of the emitting layer.

中文翻译：

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通过溶剂混合策略提高 3D 钙钛矿发光二极管性能的有效策略

摘要 在这项研究中，我们展示了一种简单的方法，通过将纯甲基溴化铵 (MABr) 在具有不同溶解度的混合溶剂中浇铸在钙钛矿层的顶部进行本体重结晶和界面钝化，从而实现高效钙钛矿发光二极管 (PeLED)。与 MABr 反应的钙钛矿晶体可以有序、立体地重组，表面畴尺寸减小，块体晶界减小，有利于获得强荧光强度和长激子寿命。剩余的不与钙钛矿反应的 MABr 分子可以附着在重结晶的钙钛矿表面形成钝化层，这可以有效地消除 PeLED 中激子界面的复合。优化后的 PeLED 的最大亮度为 27692.2 cd m−2，比未经MABr处理的控制装置和具有高MABr摩尔比和薄钙钛矿膜厚度的控制装置分别高11倍和2倍以上。这项工作提供了一种有效的策略，通过优化混合溶剂比例和有机配体 MABr 的浓度而不改变发光层的厚度来提高 PeLED 的性能。