Author(s): Bi, CH (Bi, Chenghao); Yao, ZW (Yao, Zhiwei); Sun, XJ (Sun, Xuejiao); Wei, XC (Wei, Xuecheng); Wang, JX (Wang, Junxi); Tian, JJ (Tian, Jianjun)

Source: ADVANCED MATERIALS Article Number: 2006722 DOI: 10.1002/adma.202006722 Early Access Date: FEB 2021

Abstract: 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 (approximate to 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 (approximate to 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.

Accession Number: WOS:000621452200001

PubMed ID: 33629762

Author Identifiers:

Author        Web of Science ResearcherID        ORCID Number

Tian, Jianjun         A-8647-2013         0000-0002-4008-0469

ISSN: 0935-9648

eISSN: 1521-4095

Full Text: https://onlinelibrary.wiley.com/doi/10.1002/adma.202006722