Perovskite Quantum Dots with Ultralow Trap Density by Acid Etching‐Driven Ligand Exchange for High Luminance and Stable Pure‐Blue Light‐Emitting Diodes,Advanced Materials

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Perovskite Quantum Dots with Ultralow Trap Density by Acid Etching‐Driven Ligand Exchange for High Luminance and Stable Pure‐Blue Light‐Emitting Diodes
Advanced Materials ( IF 27.4 ) Pub Date : 2021-02-25 , DOI: 10.1002/adma.202006722
Chenghao Bi ₁ , Zhiwei Yao ₁ , Xuejiao Sun ₂ , Xuecheng Wei ₂ , Junxi Wang ₂ , Jianjun Tian ₁

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The research on metal halide perovskite light‐emitting diodes (PeLEDs) with green and infrared emission has demonstrated significant progress in achieving higher functional performance. However, the realization of stable pure‐blue (≈470 nm wavelength) PeLEDs with increased brightness and efficiency still constitutes a considerable challenge. Here, a novel acid etching‐driven ligand exchange strategy is devised for achieving pure‐blue emitting small‐sized (≈4 nm) CsPbBr₃ perovskite quantum dots (QDs) with ultralow trap density and excellent stability. The acid, hydrogen bromide (HBr), is employed to etch imperfect [PbBr₆]⁴⁻ octahedrons, thereby removing surface defects and excessive carboxylate ligands. Subsequently, didodecylamine and phenethylamine are successively introduced to bond the residual uncoordinated sites of the QDs and attain in situ exchange with the original long‐chain organic ligands, resulting in near‐unity quantum yield (97%) and remarkable stability. The QD‐based PeLEDs exhibit pure‐blue electroluminescence at 470 nm (corresponding to the Commission Internationale del'Eclairage (CIE) (0.13, 0.11) coordinates), an external quantum efficiency of 4.7%, and a remarkable luminance of 3850 cd m⁻², which is the highest brightness reported so far for pure‐blue PeLEDs. Furthermore, the PeLEDs exhibit robust durability, with a half‐lifetime exceeding 12 h under continuous operation, representing a record performance value for blue PeLEDs.

中文翻译：

通过酸蚀驱动配体交换具有超低陷阱密度的钙钛矿量子点，可实现高亮度和稳定的纯蓝色发光二极管

对具有绿色和红外发射的金属卤化物钙钛矿发光二极管（PeLED）的研究表明，在实现更高的功能性能方面取得了重大进展。然而，稳定的纯蓝色（的实现≈具有增加的亮度和效率470的波长）仍然PeLEDs构成相当大的挑战。在此，一种新型的酸蚀刻驱动配位体交换的策略被设计用于实现纯蓝色发光的小尺寸（≈ 4纳米）CsPbBr ₃钙钛矿量子点（QD）具有超低陷阱密度和优异的稳定性。酸溴化氢（HBr）用于蚀刻不完美的[PbBr ₆ ] ^4-八面体，从而消除表面缺陷和过多的羧酸盐配体。随后，先后引入十二烷基胺和苯乙胺以键合量子点的残留未配位位点，并与原始的长链有机配体实现原位交换，从而获得近统一的量子产率（97％）和出色的稳定性。基于QD-PeLEDs表现出纯蓝色电致发光在470nm（对应于委员会国际歌del'Eclairage（CIE）（0.13，0.11）坐标），4.7％的外量子效率，和3850 CD米一个显着的亮度^{- 2个}，这是迄今为止纯蓝色PeLED所报告的最高亮度。此外，PeLED具有强大的耐用性，在连续运行下的半衰期超过12小时，代表了蓝色PeLED的创纪录的性能值。

更新日期：2021-04-14

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