Issue 10, 2021

Luminance efficiency roll-off mechanism in CsPbBr3−xClx mixed-halide perovskite quantum dot blue light-emitting diodes

Abstract

Efficiency roll-off is a significant issue in blue light-emitting diodes (LEDs), but its origin still remains controversial. We report CsPbBr3−xClx/PbBry (or PbCly) (core/shell) quantum dot LEDs exhibiting the emission peak spanning from λpeak = 492 to λpeak = 435 nm by varying the Cl composition (0 ≤ x ≤ 2.21). PLQY and EQE significantly decreased with the increase of the Cl composition. Careful analyses of the composition and the energy structure using EL, PL, TRPL, UPS, XPS and STEM-EDX measurements reveal that the luminance efficiency roll-off in CsPbBr3−xClx LEDs is attributed to the following three combined effects: (1) luminescence quenching by the non-radiative trap-assisted recombination, (2) the hole transfer process at the CsPbBr3−xClx/PbBry core/shell, and (3) imbalanced charge injection caused by a high energy barrier for the hole conduction at the PVK/QD heterointerface (Δh′).

Graphical abstract: Luminance efficiency roll-off mechanism in CsPbBr3−xClx mixed-halide perovskite quantum dot blue light-emitting diodes

Supplementary files

Article information

Article type
Paper
Submitted
24 noy 2020
Accepted
18 yan 2021
First published
20 yan 2021

J. Mater. Chem. C, 2021,9, 3608-3619

Luminance efficiency roll-off mechanism in CsPbBr3−xClx mixed-halide perovskite quantum dot blue light-emitting diodes

Y. R. Park, H. H. Kim, S. Eom, W. K. Choi, H. Choi, B. R. Lee and Y. Kang, J. Mater. Chem. C, 2021, 9, 3608 DOI: 10.1039/D0TC05514J

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