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Research Article | Online first | Published: 14 March 2024

Investigation of operation and degradation mechanisms in ZnTeSe blue quantum-dot light-emitting diodes by identifying recombination zone

Show Author's Information Oul Cho1,2,  Sujin Park1,2,  Hogeun Chang2,  Jiwhan Kim2,  Jaekwon Kim1,  Sungwoo Kim2,  Taehyung Kim2( ),  Jeonghun Kwak1( )
Department of Electrical and Computer Engineering, Inter-university Semiconductor Research Center, and Soft Foundry Institute, Seoul National University, Seoul 08826, Republic of Korea
Material Research Center, Samsung Advanced Institute of Technology, Suwon, Gyeonggi-do 16419, Republic of Korea
Keywords:
quantum dots, light-emitting diodes, degradation, carrier dynamics, recombination zones
Topics:
Light emitting diodes Nanocrystals
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Cho O, Park S, Chang H, et al. Investigation of operation and degradation mechanisms in ZnTeSe blue quantum-dot light-emitting diodes by identifying recombination zone. Nano Research, 2024, https://doi.org/10.1007/s12274-024-6541-5
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Abstract Full text Electronic supplementary material About this article

ZnTeSe quantum dots (QDs), recognized as promising eco-friendly blue electroluminescent emitters, remain under-explored in light-emitting diode (LED) applications. Here, to elucidate the operation and degradation mechanisms of ZnTeSe blue QD-LEDs, stacked ZnTeSe QD layers with discernable luminescence are designed by varying Te doping concentrations, and the recombination zones (RZs) of the blue QD-LEDs are investigated. The RZs are identified near the hole-transport layer (HTL), confirmed by angular-dependent electroluminescence measurements and optical simulations. In addition, in order to investigate carrier dynamics in the process of recombination, the transient electroluminescence (tr-EL) signals of the dichromatic QD-LEDs are analyzed. As a result, it is inferred that the RZ initially formed near the electron-transport layer (ETL) due to the high injection barriers of electrons. However, due to the fast electron mobility, the RZ shifts toward the HTL as the operating current increases. After the device lifetime tests, the RZ remains stationary while the photoluminescence (PL) corresponding to the RZ undergoes a substantial decrease, indicating that the degradation is accelerated by the concentrated RZ. Thus this study contributes to a deeper understanding of the operational mechanisms of ZnTeSe blue QD-LEDs.


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Electronic supplementary material
About this article

Investigation of operation and degradation mechanisms in ZnTeSe blue quantum-dot light-emitting diodes by identifying recombination zone

Show Author's information Oul Cho1,2, Sujin Park1,2, Hogeun Chang2, Jiwhan Kim2, Jaekwon Kim1, Sungwoo Kim2, Taehyung Kim2( ), Jeonghun Kwak1( )
Department of Electrical and Computer Engineering, Inter-university Semiconductor Research Center, and Soft Foundry Institute, Seoul National University, Seoul 08826, Republic of Korea
Material Research Center, Samsung Advanced Institute of Technology, Suwon, Gyeonggi-do 16419, Republic of Korea

Abstract

ZnTeSe quantum dots (QDs), recognized as promising eco-friendly blue electroluminescent emitters, remain under-explored in light-emitting diode (LED) applications. Here, to elucidate the operation and degradation mechanisms of ZnTeSe blue QD-LEDs, stacked ZnTeSe QD layers with discernable luminescence are designed by varying Te doping concentrations, and the recombination zones (RZs) of the blue QD-LEDs are investigated. The RZs are identified near the hole-transport layer (HTL), confirmed by angular-dependent electroluminescence measurements and optical simulations. In addition, in order to investigate carrier dynamics in the process of recombination, the transient electroluminescence (tr-EL) signals of the dichromatic QD-LEDs are analyzed. As a result, it is inferred that the RZ initially formed near the electron-transport layer (ETL) due to the high injection barriers of electrons. However, due to the fast electron mobility, the RZ shifts toward the HTL as the operating current increases. After the device lifetime tests, the RZ remains stationary while the photoluminescence (PL) corresponding to the RZ undergoes a substantial decrease, indicating that the degradation is accelerated by the concentrated RZ. Thus this study contributes to a deeper understanding of the operational mechanisms of ZnTeSe blue QD-LEDs.

Keywords: quantum dots, light-emitting diodes, degradation, carrier dynamics, recombination zones

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Publication history
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Acknowledgements

Publication history

Received: 23 November 2023
Revised: 13 January 2024
Accepted: 02 February 2024
Published: 14 March 2024

Copyright

© Tsinghua University Press 2024

Acknowledgements

Acknowledgements

The authors thank Samsung Advanced Institute of Technology at Samsung Electronics Co., Ltd. for the financial support.

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