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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Unraveling the Origin of Operational Instability of Quantum Dot Based Light-Emitting Diodes

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Author(s):
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Chang, Jun Hyuk [1] ; Park, Philip [2] ; Jung, Heeyoung [3] ; Jeong, Byeong Guk [4] ; Hahm, Donghyo [1] ; Nagamine, Gabriel [5] ; Ko, Jongkuk [6] ; Cho, Jinhan [6] ; Padilha, Lazaro A. [5] ; Lee, Doh C. [4] ; Lee, Changhee [3] ; Char, Kookheon [1] ; Bae, Wan Ki [7]
Total Authors: 13
Affiliation:
[1] Seoul Natl Univ, Sch Chem & Biol Engn, Seoul 08826 - South Korea
[2] Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 - USA
[3] Seoul Natl Univ, Sch Elect & Comp Engn, Interuniv Semicond Res Ctr, Seoul 08826 - South Korea
[4] Korea Adv Inst Sci & Technol, KAIST Inst NanoCentury, Dept Chem & Biomol Engn, Daejeon 34141 - South Korea
[5] Univ Estadual Campinas, Inst Fis Gleb Wataghin, UNICAMP, POB 6165, BR-13083859 Campinas, SP - Brazil
[6] Korea Univ, Dept Chem & Biol Engn, Seoul 02841 - South Korea
[7] Sungkyunkwan Univ, SKKU Adv Inst Nanotechnol SAINT, Suwon 16419, Gyeonggi Do - South Korea
Total Affiliations: 7
Document type: Journal article
Source: ACS NANO; v. 12, n. 10, p. 10231-10239, OCT 2018.
Web of Science Citations: 11
Abstract

We investigate the operational instability of quantum dot (QD)-based light-emitting diodes (QLEDs). Spectroscopic analysis on the QD emissive layer within devices in chorus with the optoelectronic and electrical characteristics of devices discloses that the device efficiency of QLEDs under operation is indeed deteriorated by two main mechanisms. The first is the luminance efficiency drop of the QD emissive layer in the running devices owing to the accumulation of excess electrons in the QDs, which escalates the possibility of nonradiative Auger recombination processes in the QDs. The other is the electron leakage toward hole transport layers (HTLs) that accompanies irreversible physical damage to the HTL by creating nonradiative recombination centers. These processes are distinguishable in terms of the time scale and the reversibility, but both stem from a single origin, the discrepancy between electron versus hole injection rates into QDs. Based on experimental and calculation results, we propose mechanistic models for the operation of QLEDs in individual quantum dot levels and their degradation during operation and offer rational guidelines that promise the realization of high-performance QLEDs with proven operational stability. (AU)

FAPESP's process: 13/16911-2 - Advanced spectroscopy of novel nanomaterials
Grantee:Lázaro Aurélio Padilha Junior
Support Opportunities: Research Grants - Young Investigators Grants