Exciton dynamics in colloidal quantum-dot leds under active device operations
Colloidal quantum-dot light-emitting diodes (QLEDs) are lucrative options for color-pure lighting sources. To achieve high-performance QLEDs, besides developing high-efficiency quantum dots (QDs), it is essential to understand their device physics. However, little understanding of the QD emission be...
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sg-ntu-dr.10356-889502023-02-28T19:31:57Z Exciton dynamics in colloidal quantum-dot leds under active device operations Shendre, Sushant Sharma, Vijay Kumar Dang, Cuong Demir, Hilmi Volkan School of Electrical and Electronic Engineering School of Physical and Mathematical Sciences Centre of Excellence for Semiconductor Lighting and Displays The Photonics Institute Exciton Dynamics Electroluminescence DRNTU::Engineering::Electrical and electronic engineering Colloidal quantum-dot light-emitting diodes (QLEDs) are lucrative options for color-pure lighting sources. To achieve high-performance QLEDs, besides developing high-efficiency quantum dots (QDs), it is essential to understand their device physics. However, little understanding of the QD emission behavior in active QLEDs is one of the main factors hindering the improvement of device efficiency. In this work, we systematically studied the exciton dynamics of gradient composition CdSe@ZnS QDs during electroluminescence in a working QLED. With time-resolved photoluminescence analyses using fluorescence lifetime imaging microscopy we analyzed a large population of QDs spatially spreading over an extended area inside and outside the device. This allows us to reveal the statistically significant changes in the behavior of QD emission in the device at different levels of applied voltages and injection currents. We find that the QD emission efficiency first drops in device fabrication with Al electrode deposition and that the QD exciton lifetime is then statistically reduced further under the QLED’s working conditions. This implies the nonradiative Auger recombination process is active in charged QDs as a result of imbalanced charge injection in a working QLED. Our results help to understand the exciton behavior during the operation of a QLED and demonstrate a new approach to explore the exciton dynamics statistically with a large QD population. NRF (Natl Research Foundation, S’pore) ASTAR (Agency for Sci., Tech. and Research, S’pore) Accepted version 2019-05-24T01:31:13Z 2019-12-06T17:14:25Z 2019-05-24T01:31:13Z 2019-12-06T17:14:25Z 2018 Journal Article Shendre, S., Sharma, V. K., Dang, C., & Demir, H. V. (2017). Exciton Dynamics in Colloidal Quantum-Dot LEDs under Active Device Operations. ACS Photonics, 5(2), 480-486. doi:10.1021/acsphotonics.7b00984 https://hdl.handle.net/10356/88950 http://hdl.handle.net/10220/48349 10.1021/acsphotonics.7b00984 en ACS Photonics © 2017 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Photonics, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acsphotonics.7b00984. 22 p. application/pdf |
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Exciton Dynamics Electroluminescence DRNTU::Engineering::Electrical and electronic engineering Shendre, Sushant Sharma, Vijay Kumar Dang, Cuong Demir, Hilmi Volkan Exciton dynamics in colloidal quantum-dot leds under active device operations |
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Colloidal quantum-dot light-emitting diodes (QLEDs) are lucrative options for color-pure lighting sources. To achieve high-performance QLEDs, besides developing high-efficiency quantum dots (QDs), it is essential to understand their device physics. However, little understanding of the QD emission behavior in active QLEDs is one of the main factors hindering the improvement of device efficiency. In this work, we systematically studied the exciton dynamics of gradient composition CdSe@ZnS QDs during electroluminescence in a working QLED. With time-resolved photoluminescence analyses using fluorescence lifetime imaging microscopy we analyzed a large population of QDs spatially spreading over an extended area inside and outside the device. This allows us to reveal the statistically significant changes in the behavior of QD emission in the device at different levels of applied voltages and injection currents. We find that the QD emission efficiency first drops in device fabrication with Al electrode deposition and that the QD exciton lifetime is then statistically reduced further under the QLED’s working conditions. This implies the nonradiative Auger recombination process is active in charged QDs as a result of imbalanced charge injection in a working QLED. Our results help to understand the exciton behavior during the operation of a QLED and demonstrate a new approach to explore the exciton dynamics statistically with a large QD population. |
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School of Electrical and Electronic Engineering |
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School of Electrical and Electronic Engineering Shendre, Sushant Sharma, Vijay Kumar Dang, Cuong Demir, Hilmi Volkan |
format |
Article |
author |
Shendre, Sushant Sharma, Vijay Kumar Dang, Cuong Demir, Hilmi Volkan |
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Shendre, Sushant |
title |
Exciton dynamics in colloidal quantum-dot leds under active device operations |
title_short |
Exciton dynamics in colloidal quantum-dot leds under active device operations |
title_full |
Exciton dynamics in colloidal quantum-dot leds under active device operations |
title_fullStr |
Exciton dynamics in colloidal quantum-dot leds under active device operations |
title_full_unstemmed |
Exciton dynamics in colloidal quantum-dot leds under active device operations |
title_sort |
exciton dynamics in colloidal quantum-dot leds under active device operations |
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2019 |
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https://hdl.handle.net/10356/88950 http://hdl.handle.net/10220/48349 |
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1759858046204379136 |