High efficient OLED displays prepared with the air-gapped bridges on quantum dot patterns for optical recycling

Kim, Hyo Jun; Shin, Min Ho; Kim, Joo Suc; Kim, Se Eun; Kim, Young Joo

doi:10.1038/srep43063

Cited by 12 publications

(5 citation statements)

References 33 publications

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“…A photolithography process was carried out for the QD PR on the glass substrate, then a full-color OLED display was fabricated. Compared with traditional OLED displays, the luminance intensity of red and green sub-pixels has been improved by 32.1% and 9.6% respectively after the use of QD [13].…”

Section: > Replace This Line With Your Manuscript Id Number (Double-c...mentioning

confidence: 96%

“…As a result, micron-level thick QD film with even surface morphology can be obtained, and high-efficiency color conversion efficiency can be realized. Additionally, the thickness of the QD layer can be varied to adjust the light conversion efficiency [13]. Zhiping Hu et al [14] combined blue OLED with red and green QDs.…”

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confidence: 99%

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Flexible White Lighting Fabricated With Quantum Dots Color Conversion Layers Excited by Blue Organic Light-Emitting Diodes

et al. 2022

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Section: > Replace This Line With Your Manuscript Id Number (Double-c...mentioning

confidence: 96%

Section: > Replace This Line With Your Manuscript Id Number (Double-c...mentioning

confidence: 99%

Flexible White Lighting Fabricated With Quantum Dots Color Conversion Layers Excited by Blue Organic Light-Emitting Diodes

et al. 2022

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“…After that, an air-gapped bridge structure was added between the OLED and the QDs to achieve a full internal reflection (FIR) that performed an optical cycle to improve the QDs' color conversion efficiency. The light intensity of the red and green sub-pixels increased by 58.2% and 16.8%, respectively, and due to the narrow emission spectrums of the QDs, the color space of the proposed OLED screen increased by 65%, from 5% to 75.9% [16]. Jung Hyuk Im et al Hongik University in South Korea investigated the color conversion properties of QDs/OLEDs using the microcavity effect, with OLEDs fabricated on WO 3 /Ag/WO 3 (WAW) anodes.…”

Section: Introductionmentioning

confidence: 99%

Quantum Dot-Based White Organic Light-Emitting Diodes Excited by a Blue OLED

et al. 2022

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In this study, white organic light-emitting diodes (OLEDs) consisting of red quantum dots (RQD) and green quantum dots (GQD) were investigated. These are the most exciting new lighting technologies that have grown rapidly in recent years. The white OLED development processes used consisted of the following methods: (a) fabrication of a blue single-emitting layer OLED, (b) nanoimprinting into QD photoresists, and (c) green and red QD photoresists as color conversion layers (CCL) excited by blue OLEDs. To fabricate the blue OLED, the HATCN/TAPC pair was selected for the hole injection/transport layer on ITO and TPBi for the electron transport layer. For blue-emitting material, we used a novel polycyclic framework of thermally activated delayed fluorescence (TADF) material, ν-DABNA, which does not utilize any heavy metals and has a sharp and narrow (FWHM 28 nm) electroluminescence spectrum. The device structure was ITO/HATCN (20 nm)/TAPC (30 nm)/MADN: ν-DABNA (40 nm)/TPBi (30 nm)/LiF (0.8 nm)/Al (150 nm) with an emitting area of 1 cm × 1 cm. The current density, luminance, and efficiency of blue OLEDs at 8 V are 87.68 mA/cm2, 963.9 cd/m2, and 1.10 cd/A, respectively. Next, the bottom emission side of the blue OLED was attached to nanoimprinted RQD and GQD photoresists, which were excited by the blue OLED in order to generate an orange and a green color, respectively, and combined with blue light to achieve a nearly white light. In this study, two different excitation architectures were tested: BOLED➔GQD➔RQD and BOLED➔RQD➔GQD. The EL spectra showed that the BOLED➔GQD➔RQD architecture had stronger green emissions than BOLED➔RQD➔GQD because the blue OLED excited the GQD PR first then RQD PR. Due to the energy gap architectures in BOLED-GQD-RQD, the green QD absorbed part of the blue light emitted from the BOLED, and the remaining blue light penetrated the GQD to reach the RQD. These excited spectra were very close to the white light, which resulted in three peaks emitting at 460, 530, and 620 nm. The original blue CIE coordinates were (0.15, 0.07). After the excitation combination, the CIE coordinates were (0.42, 0.33), which was close to the white light position.

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“…Quantum dots (QD) have been widely used in display fields due to their unique optical properties such as high quantum yield, broad absorption, and narrow emission bands [1]. In previous researches, we proposed and published new approaches to improve the optical efficiencies of white organic light emitting diodes (OLED) display and liquid-crystal display (LCD) by applying the patterned QD film dispersed in photoresist (PR) to down-covert the blue light to necessary green or red light [2]- [4]. However, both technical limitations of thin film thickness (about 2m) and relatively low QD concentration (maximum 20 wt%) of the patterned QD film made it difficult to absorb all the blue light in thin QD film.…”

Section: Introductionmentioning

confidence: 99%

52.2: Invited Paper: Application of Quantum‐dot Patterned Film with Scattering Nanoparticles for the High Efficiency Displays

Kim

et al. 2019

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Quantum dot (QD) as a color converting material in the form of patterned film can effectively improve the optical efficiency of displays. Since all of the light passing through the QD film cannot be fully down‐converted, however, novel structure or materials are required to improve the light down‐converting efficiency in the QD film. TiO2 and wrinkled silica particles are respectively applied as scattering nanoparticles which can increase optical path of light in this study. From experimental results, it was confirmed that optical efficiencies of red and green light in white OLED prepared with QD and TiO2 were enhanced further by 57.3% and 17.5%, respectively. In addition, the QD‐converting efficiency to green light from blue µ‐LED was increased using wrinkled silica‐QD hybrid particles, resulting in the enhanced luminous efficacy of 13.1lm/W with 15wt% QD concentration.

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High efficient OLED displays prepared with the air-gapped bridges on quantum dot patterns for optical recycling

Cited by 12 publications

References 33 publications

Flexible White Lighting Fabricated With Quantum Dots Color Conversion Layers Excited by Blue Organic Light-Emitting Diodes

Flexible White Lighting Fabricated With Quantum Dots Color Conversion Layers Excited by Blue Organic Light-Emitting Diodes

Quantum Dot-Based White Organic Light-Emitting Diodes Excited by a Blue OLED

52.2: Invited Paper: Application of Quantum‐dot Patterned Film with Scattering Nanoparticles for the High Efficiency Displays

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