High efficiency and ultra-wide color gamut quantum dot LEDs for next generation displays

Manders, Jesse R.; Liu, Qian; Titov, Alexandre; Hyvonen, Jake; Tokarz-Scott, Jean; Acharya, Krishna Prasad; Yang, Yixing; Cao, Weiran; Zheng, Ying; Xue, Jiangeng; Holloway, Paul H.

doi:10.1002/jsid.393

Cited by 109 publications

(64 citation statements)

References 15 publications

(36 reference statements)

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“…These superiorities make QLEDs promising candidates for new generation display technology. [1][2][3][4][5][6][7][8] With the rapid development of QD materials and device structures, the performances of red and green devices have been substantially improved; for example, the external quantum efficiencies (EQE) of red and green QLEDs have reached 20.5% 1 and 21% 9 and they have been lately improved from 23.1% to 27.6% by using tandem structures, 10 which are very close to those of organic LEDs (OLEDs). 11,12 And blue QLEDs with EQE of 19.8% 13 and 21.4% 10 have also been reported very recently.…”

Section: Introductionmentioning

confidence: 99%

The influence of the hole transport layers on the performance of blue and color tunable quantum dot light‐emitting diodes

Huang

et al. 2018

J Soc Info Display

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The performance of the blue quantum dot light‐emitting diodes (QLEDs) is largely affected by the hole transport layers (HTLs). As a consequence of the deep valance band level of blue quantum dots (QDs), hole injection is relatively difficult in blue QLEDs. To favor the hole injection, HTLs with high hole mobility and deep‐lying highest occupied molecular orbital level are desired. In this work, various HTLs and their influence on the performance of blue QLEDs are demonstrated. Devices with poly(N‐vinylcarbazole) (PVK) HTL exhibit the highest external quantum efficiency while devices with poly[9,9‐dioctylfluorene‐co‐N‐(4‐(3‐methylpropyl))‐diphenylamine] (TFB) exhibit the lowest driving voltage. By combining the advantages of PVK and TFB, the blue QLEDs with TFB/PVK bilayered HTL simultaneously exhibit a low driving voltage of 2.6 V and a high external quantum efficiency of 5.9%. Moreover, the exciplex emission at the interface of HTL/QDs is also observed, and the emission intensity can be tuned by modulating the hole injection. By utilizing PVK doped with 25% poly(3‐hexylthiophene) (P3HT) as HTL, exciplex emission is significantly enhanced at low driving voltage while QD emission is dominant at high driving voltage. By combining the exciplex emission and the QD emission, the emission color can be effectively tuned from red to blue as the driving voltage changing from 2 to 10 V.

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Section: Introductionmentioning

confidence: 99%

The influence of the hole transport layers on the performance of blue and color tunable quantum dot light‐emitting diodes

Huang

et al. 2018

J Soc Info Display

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“…For example, red devices with an external quantum efficiency (EQE) of 20.5 %, 2 and with a lifetime in excess of 300,000 hours for a brightness of 100 cd/m 2 , 3 have been reported. For green, an EQE of 21 % at a luminance of 1,000 cd/m 2 has been achieved, 4 while for blue the highest reported EQE is 11.2 %. 5 However, the performance of heavy metal-free QD devices remains low.…”

Section: Electroluminescencementioning

confidence: 95%

39‐4: Invited Paper: Innovation in Heavy Metal‐Free Quantum Dot Technology

Pickett

Gresty

2017

Symp Digest of Tech Papers

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“…Narrow bandwidth emitters with adjustable peak emissions that are aligned with the LCD color filter transmittance enable a wide gamut with high efficiency. Quantum dot (QD) technology, in which QDs down‐convert absorbed radiation into a lower frequency emission, effectively fills this need . A peak wavelength emission that is highly tunable to ±1 nm by selection of particle size, with a full width half maximum bandwidth that is 30 nm or less, and a quantum yield that is in excess of 90% is desirable.…”

Section: Objective and Backgroundmentioning

confidence: 99%

Design considerations for highly efficient edge‐lit quantum dot displays

Twietmeyer¹,

Sadasivan²

2016

J Soc Info Display

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Quantum Dots (QDs) are increasingly the technology of choice for wide color gamut displays. Two popular options to incorporate QDs into displays include on-edge and on-surface solutions. The opto-mechanical design for an on-edge QD solution is more complex than the design for a standard white phosphor LED light bar. In this paper, we identify and investigate a range of design parameters for an on-edge QD light bar, and we show that these parameters have significant influence on system efficiency and color uniformity. The effects of varying these parameters are explored through the use of a custom adjustable testbed and optical raytracing methods. Our testbed data demonstrate the inherent tradeoffs between efficiency and color uniformity and provide guidance for the design of high performing displays. The optical raytracing data demonstrate a good predictive capability and support the use of optical modeling methods for a detailed exploration of a wider range of design parameters. Author Keywordsquantum dot; wide color gamut; edge optic; backlight unit; optical raytracing. Objectives and BackgroundA current major trend in display technology is towards wide color gamut [1][2]. Wide gamut displays provide more highly saturated colors which appear brighter than less saturated colors at the same luminance [1]. Multiple studies have suggested that higher gamut content receives increased attention [3][4]. Highly accurate color representation is required for viewing of native DCI and Adobe RGB content, as well as the production of true ultra high definition and cinema quality displays. Narrow bandwidth emitters with adjustable peak emissions that are aligned with the LCD color filter transmittance enable a wide gamut with high efficiency. Quantum Dot (QD) technology, in which QDs downconvert absorbed radiation into a lower frequency emission, effectively fills this need [5][6]. A peak wavelength emission that is highly tunable to ± 1 nm by selection of particle size, with a full width half maximum bandwidth that is 30 nm or less and a quantum yield that is in excess of 90% is desirable. In a typical display usage, blue excitation light from GaN LEDs is downconverted by QDs to green and red light. The combination of blue excitation light and QD-generated green and red light gives white light with distinct, narrow spectral peaks. QD based backlight units (BLUs) can be produced at a price point similar to that of the standard white LED BLUs, which have a substantially lower gamut. Mass production of QDs and integration into existing backlight manufacturing processes have been demonstrated in commercially available displays, including Sony Triluminos TVs, Hisense TVs, TCL TVs, and Philips TVs and monitors.Options for incorporating QDs into a BLU include on-edge, onsurface (e.g., film), and on-chip (e.g., direct lit) configurations. This paper considers the on-edge solution, in which a glass tube containing red and green emitting QDs is located along one or more edges of the BLU between the blue LED light bar and the ...

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High efficiency and ultra-wide color gamut quantum dot LEDs for next generation displays

Cited by 109 publications

References 15 publications

The influence of the hole transport layers on the performance of blue and color tunable quantum dot light‐emitting diodes

The influence of the hole transport layers on the performance of blue and color tunable quantum dot light‐emitting diodes

39‐4: Invited Paper: Innovation in Heavy Metal‐Free Quantum Dot Technology

Design considerations for highly efficient edge‐lit quantum dot displays

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