Electric Field Inhomogeneity in Colloidal QD‐LEDs
Name
Advanced Optical Materials - 2025 - Srinivasan - Electric Field Inhomogeneity in Colloidal QD‐LEDs.pdf
Description
Published version
Size
6.48 MB
Format
Adobe PDF
Checksum (MD5)
9bc41aab72277a2f02ec88539a38402b
Author(s)
Srinivasan, Shreyas
Zhang, Ruiqi
Dillender, Mike
Nguyen, Thienan
Laitz, Madeleine
Kim, Taehyung
Kim, Kwang‐Hee
Kim, Tae‐Gon
Bawendi, Moungi
Bulović, Vladimir
Date Issued
June 13, 2025
Journal
Advanced Optical Materials
Publisher
Wiley
Citation
S. Srinivasan, R. Zhang, M. Dillender, T. Nguyen, M. Laitz, T. Kim, K.-H. Kim, T.-G. Kim, M. Bawendi, V. Bulović, Electric Field Inhomogeneity in Colloidal QD-LEDs. Adv. Optical Mater. 2025, 13, 2500058.
Version
Final published version
Abstract
It is demonstrated that the electroluminescent layer in a colloidal quantum dotlight emitting diode (QD-LED), formed by stochastic methods such as spin-coating, incorporates morphological thickness inhomogeneities, resulting inlocal electric field variations. These inhomogeneities can be directly visualizedand quantified using confocal micro-photoluminescence (PL) and micro-electroluminescence (EL), as showed in QD-LEDs with stochastically processedInP/ZnSe/ZnS colloidal quantum dots (QDs). Around 5% of the device showsEL darkspots under forward bias and PL hotspots under photoexcitation,with a strong spatial correlation between these features. The PL hotspots(EL darkspots) correspond to thicker regions in the stochastically-processedQD film. This thickness variation leads to two distinct QD sub-populationsresponding differently to optical excitation. Time and energy-resolved spectraldiffusion measurements reveal that most excitons belong to a “more-mobile”sub-population with fast energy transfer and short, electric field-dependentlifetimes, while a smaller fraction belongs to a “less-mobile” sub-populationwith slower energy transfer and longer, electric field-independentlifetimes. The “less-mobile” excitons correlate with thicker QD regions. Thesefindings shed light on the local electric field inhomogeneity in QD-LEDs,offering insights into device operation, possible degradation mechanisms,and strategies for developing stochastically-processed micro-QD-LEDs.
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
Massachusetts Institute of Technology. Research Laboratory of Electronics
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
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Creative Commons Attribution-NonCommercial-NoDerivatives
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DOI of Published Version
https://doi.org/10.1002/adom.202500058
