CsPbX₃ nanocrystal (NC)-based blue perovskite light-emitting diodes (PeLEDs) are still in a backward position while their green and red counterparts have achieved significant progress in the past few years. The emission spectrum of perovskite NCs can be manipulated via the ratio control of halides in precursor or halogen exchange of NCs. Herein, CsPbBr_xCl_3–x NCs are synthesized in ambient condition. With tetrabutylammonium p-toluenesulfonate (TBSA) added as the ligand during the purification process of as-synthesized perovskite NCs, bromine in NCs is substituted by chlorine and the spectrum undergoes a blue shift, whereas chlorine is exchanged by bromine in NCs and the spectrum undergoes a red shift by introducing sodium dodecylbenzenesulfonate (SDSA) as the ligand. The origin for halogen exchange can be attributed to the synergistic effects of the anion and cation of benzenesulfonates. The photoluminescence quantum yield (PLQY) of NCs increases from 7% to 81% due to the effective passivating effects of the strong ionic sulfonate heads, and the blue PeLEDs prepared by this method show a promising external quantum efficiency of 2.6%. Our work provides a new approach into spectral tuning of efficient blue PeLEDs.

中文翻译：

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高效CsPbBr的光谱调谐_X氯_{-3- X}蓝色发光二极管通过卤素交换苯磺酸触发

基于CsPbX ₃纳米晶体（NC）的蓝色钙钛矿发光二极管（PeLED）仍处于落后地位，而其绿色和红色对应物在过去几年中已取得显着进步。钙钛矿型NC的发射光谱可以通过控制NC的前驱体或卤素交换中卤化物的比例控制。在此，CsPbBr _x Cl _{3– x} NCs在环境条件下合成。四丁基p-在合成钙钛矿NC的纯化过程中添加的甲苯磺酸盐（TBSA）作为配体，NC中的溴被氯取代，光谱发生蓝移，而NC中的溴被溴交换，氯光谱发生红移。通过引入十二烷基苯磺酸钠（SDSA）作为配体。卤素交换的起因可以归因于苯磺酸根的阴离子和阳离子的协同作用。由于强离子磺酸盐头的有效钝化作用，NC的光致发光量子产率（PLQY）从7％提高到81％，并且通过此方法制备的蓝色PeLED显示出令人鼓舞的2.6％的外部量子效率。我们的工作为高效蓝PeLED的光谱调谐提供了一种新方法。