Phase rearrangement for minimal exciton loss in a quasi-2D perovskite toward efficient deep-blue LEDs via halide post-treatment

Electroluminescence efficiencies of deep-blue quasi-two-dimensional (quasi-2D) perovskites are limited by a lack of post-treatment strategies that can both construct an ideal energy-transfer tunnel structure minimizing the exciton losses and passivate chlorine vacancies. Herein, multi-functional hal...

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Published inJournal of materials chemistry. C, Materials for optical and electronic devices Vol. 10; no. 47; pp. 17945 - 17953
Main Authors Shin, Yun Seop, Yoon, Yung Jin, Adhikari, Aniruddha, Cho, Hye Won, Song, Taehee, Park, Chan Beom, Son, Jung Geon, Kim, Gi-Hwan, Kwon, Oh-Hoon, Kim, Jin Young
Format Journal Article
LanguageEnglish
Published Cambridge Royal Society of Chemistry 08.12.2022
Subjects
Chlorine
Emitters
Energy distribution
Energy of dissociation
Energy transfer
Excitons
Lattice vacancies
Light emitting diodes
Perovskites
Phase distribution
Quantum efficiency
Transfer tunnels
Tunnel construction
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Summary:Electroluminescence efficiencies of deep-blue quasi-two-dimensional (quasi-2D) perovskites are limited by a lack of post-treatment strategies that can both construct an ideal energy-transfer tunnel structure minimizing the exciton losses and passivate chlorine vacancies. Herein, multi-functional halide post-exchange is demonstrated for fabricating efficient deep-blue quasi-2D perovskite light-emitting diodes (PeLEDs). This post-treatment suppresses detrimental chlorine vacancies in the perovskite lattice, resulting in an efficient deep-blue perovskite emitter. Synergistically, the spontaneous phase rearrangement occurs via merging between neighboring low- n phases to higher- n phases. The narrowed 2D phase distribution enhances excitonic-energy transfer to the target bulk phase with fewer energy transfer steps, each of which is accompanied by adverse energy loss by exciton dissociation. Efficient deep-blue PeLEDs with a maximum external quantum efficiency of 4.97% are realized, emitting at 470 nm. Device lifetimes are also elongated as a synergetic benefit. This work provides an effective approach as a step closer to designing high-performance deep-blue PeLEDs for practical applications.
ISSN:2050-7526
2050-7534
DOI:10.1039/D2TC04025E