Photonics Research, Volume. 10, Issue 7, 07001633(2022)

Colloidal quantum-dot light emitting diodes with bias-tunable color

Ge Mu1,2, Tianyu Rao1, Menglu Chen1,2,3, Yimei Tan3, Qun Hao1,2,3,4, and Xin Tang1,2,3,*
Author Affiliations
  • 1School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
  • 2Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology, Beijing 100081, China
  • 3Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314019, China
  • 4e-mail: qhao@bit.edu.cn
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    Although the performance of quantum-dot-based light emitting diodes (QLEDs) has been significantly enhanced over the past years, conventional full-color QLED displays still rely on the side-by-side pattern techniques of red (R)/green (G)/blue (B) quantum dots (QDs). Such lateral integration of multi-color pixels imposes technological difficulty in the development of high-resolution displays due to limited pixel density and fill factors. Herein, we demonstrate the development of full-color QLEDs with bias-tunable emission spectra by engineering mixed R/G/B QDs as light emitting layers. In Commission Internationale de l’Eclairage (CIE) chromaticity coordinates, QLEDs with bias-tunable color exhibit wide color variation ranging from red (0.649, 0.330) to green (0.283, 0.305) to blue (0.255, 0.264) upon increasing voltages and can be tuned to emit white light (0.316, 0.325). More importantly, the fabricated multi-color QLEDs show high luminance approaching 103 cd m-2 and superior external quantum efficiency of 13.3%. Benefitting from the wide spectral tunability and light emitting efficiency, we believe the proposed multi-color QLEDs have great application prospects for both displays and lighting.

    1. INTRODUCTION

    Colloidal quantum dots (QDs) have been extensively investigated as promising alternative visible emitters to traditional inorganic bulk phosphors and organic luminescent materials owing to their tunable emission wavelengths, narrow spectral bandwidths, excellent photoluminescent (PL) quantum yield, and solution-process compatibility [14]. Since the first demonstration of colloidal QD light emitting diodes (QLEDs) in 1994 [5], the performance of monochromatic QLEDs has been significantly improved including luminance, external quantum efficiency (EQE), and device stability by optimizing the device structures and material properties [610]. Although monochromatic QLEDs show excellent performance such as maximum luminance up to 23,040, 218,800, and 2250  cdm2, and EQE of 7.3%, 5.8%, and 1.7% for red (R), green (G), and blue (B) QLEDs, respectively [8], it is still challenging to obtain high-resolution full-color QLED displays [2,11,12].

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    Ge Mu, Tianyu Rao, Menglu Chen, Yimei Tan, Qun Hao, Xin Tang. Colloidal quantum-dot light emitting diodes with bias-tunable color[J]. Photonics Research, 2022, 10(7): 07001633

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    Paper Information

    Category: Optoelectronics

    Received: Feb. 11, 2022

    Accepted: May. 18, 2022

    Published Online: Jun. 20, 2022

    The Author Email: Xin Tang (xintang@bit.edu.cn)

    DOI:10.1364/PRJ.456043

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