InP-Based Quantum Dot Light-Emitting Diode with a Blended Emissive Layer

Han, Moon Gyu; Lee, Yeon-Kyung; Kwon, Ha-il; Lee, Hee Jae; Kim, Tae-Hyung; Won, Yong Hyub; Jang, Eunjoo

doi:10.1021/acsenergylett.1c00351

Cited by 54 publications

(62 citation statements)

References 42 publications

(63 reference statements)

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“…[1][2][3] The InP-based QDs have been synthesized with near-unity photoluminescence quantum yield (PL QY), which can meet the RoHS requirements by removing toxic Cd from QD emitters. [4,5] Despite recent advances in QD light-emitting diodes (QD-LEDs), including a 20% external quantum efficiency and enhanced device lifetime, [4,[6][7][8][9][10][11] multicolored and pixelated QD-LED devices still need to be developed. [12] The QDs are typically synthesized using wet chemistry, which is useful for large-scale solution processes.…”

mentioning

confidence: 99%

Nondestructive Direct Photolithography for Patterning Quantum Dot Films by Atomic Layer Deposition of ZnO

Lee

Kim

Han

et al. 2022

Adv Materials Inter

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materials because of their high color purity, large-scale solution processability, and tunable electrical and optical properties. [1][2][3] The InP-based QDs have been synthesized with near-unity photoluminescence quantum yield (PL QY), which can meet the RoHS requirements by removing toxic Cd from QD emitters. [4,5] Despite recent advances in QD light-emitting diodes (QD-LEDs), including a 20% external quantum efficiency and enhanced device lifetime, [4,[6][7][8][9][10][11] multicolored and pixelated QD-LED devices still need to be developed. [12] The QDs are typically synthesized using wet chemistry, which is useful for large-scale solution processes. When QDs are incorporated into a device structure and sandwiched into a multilayered thin film, solvent orthogonality should be considered because the pre-coated QD layer can be damaged by the solvent in the top layers. This can be a serious issue when the QD film is patterned as a pixelated display, where conventional photolithography cannot be used. [13,14] When photoresists are coated on top of the pre-existing QD film, the QD film is easily removed, or the two layers intermix. This is because QDs are easily dissolved or washed with organic solvents, which are also used to dissolve the photoresist. Thus, alternative patterning methods, such as inkjet [15][16][17][18][19] and transfer printing, [20][21][22] have been employed to form multicolor QD patterns. However, inkjet printing has a limited tact time and suffers from nozzle clogging issues for industrial applications. [15,23] In addition, transfer printing can yield high-resolution patterns, but the process requires precise control of kinetic parameters, such as pick-up and peeling speed, which limits the reproducibility of the process. [21,22] Therefore, it is highly desirable to use conventional photolithography for patterning QD films. [24] Two methods have been suggested for employing photolithography to QD film patterning. One is the addition of light-sensitive cross-linking molecules to the QD solution. The molecule can either replace the original ligands or can be included as an additional substance. [25][26][27] Upon light exposure, the molecules form a crosslinked structure between the QDs, and the patterns can be formed by solvent dipping. The other method directly uses a conventional photoresist because it is a well-designed chemical that provides high resolution and etch-resistance. Owing to the absence of solvent resistance in QD films, the lift-off method Colloidal quantum dot-based light-emitting diodes (QD-LEDs) are one of the potential future self-emissive displays owing to their large-scale solutionprocessibility and high color purity. For the industrial application of QD-LEDs, high-performance QD-LED and high-resolution patterning of quantum dot (QD) films are required. Photolithography is an ideal tool for patterning QD films. Previously, the high-resolution patterning of QD films using direct photolithography by ultra-thin atomic layer deposition of ZnO on the QD surface is reported. Th...

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confidence: 99%

Nondestructive Direct Photolithography for Patterning Quantum Dot Films by Atomic Layer Deposition of ZnO

Lee

Kim

Han

et al. 2022

Adv Materials Inter

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“…2020 [51] 5 630 10 18 128 577 ACS Energy Lett. 2021 [52] 6 625 621 © 2022 Wiley-VCH GmbH from J&K Chemical Ltd. All other organic solvents were purchased from Sinopharm Reagents. (TMS)3P were distilled prior to use and stored in glove box (carefully handled).…”

Section: Methodsmentioning

confidence: 99%

High Performance InP‐based Quantum Dot Light‐Emitting Diodes via the Suppression of Field‐Enhanced Electron Delocalization

Bian

Zhang

et al. 2022

Adv Funct Materials

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To understand the exciton dynamics due to the electron delocalization in InP-based quantum dot light-emitting diodes (QLEDs), the exciton dynamics are systematically controlled in InP-based QLEDs through varying the shell thicknesses of InP/ZnSe quantum dots (QDs) and the effective electrical field (E-field) across the QDs. It is found that the field-independent energy transfer is effectively suppressed as the shell thickness increases. However, InP/ZnSe QDs with thicker shells only have limited benefit for suppressing the exciton transfer due to field-enhanced electron delocalization in films on electron transport layers or working devices. The field-assisted exciton transfer is mainly driven by the large E-field and field-enhanced electron delocalization in InP/ZnSe QDs. External quantum efficiency of 22.56% is achieved in InPbased QLEDs by reducing the effective E-field (at 2 V bias). The breakthrough luminance of 136 090 cd/m −2 is achieved at a large bias of 7.2 V, due to the suppression of field-enhanced electron delocalization by the ultra-thick shell.

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“…Indium phosphide (InP) quantum dots (QDs) are a promising Restriction of Hazardous Substances (RoHS) directive-compliant material that can replace cadmium selenide-based QDs used in light-emitting diodes and other display technologies. − To achieve the desired optical properties for the practical utilization, optimization of the synthetic processes of InP QDs by using a low-cost, environmentally friendly phosphorus precursor, tris(dialklamino)phosphine, has been intensively studied in recent years. , The phosphorus center of tris(dialklamino)phosphine undergoes a “phosphorus nucleophilic substitution” with primary amine to form InP . This complex nucleation and growth process usually results in polydispersed particle sizes of InP QDs, which broadens the photoluminescence (PL) at full width at half-maximum (fwhm) and reduces the color purity of InP QDs. , At the same time, the easy oxidative nature and abundant dangling bonds of the InP QDs cause a significant nonradiative recombination of charge carriers which depresses the PL quantum yield (QY). , Therefore, the development of better synthesis as well as effective passivation protocol and understanding of the charge carrier dynamics of the InP QDs are vital for further advances in practical optoelectronic technology and applications. − …”

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Effects of Interfacial Oxidative Layer Removal on Charge Carrier Recombination Dynamics in InP/ZnSe_xS_1–x Core/Shell Quantum Dots

Fan

Chang

et al. 2021

J. Phys. Chem. Lett.

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Red-light-emitting InP/ZnSe x S 1−x core/shell quantum dots (QDs) were prepared by one-pot synthesis with optimal hydrogen fluoride (HF) treatment. Most of the surficial oxidative species could be removed, and the dangling bonds would be passivated by Zn ions for the InP cores during HF treatment, which would be beneficial to the subsequent ZnSe x S 1−x shell coating. Three-dimensional time-resolved photoluminescence spectra of the QD samples were analyzed by singular value decomposition global fitting to determine the radiative and nonradiative lifetimes of charge carriers. A proposed model illustrated that the charge carriers in the InP/ZnSe x S 1−x QDs with interfacial oxidative layer removal would evidently recombine through radiative pathways, mainly from the conduction band to the valence band (lifetime, 33 ns) and partially from the trap states (lifetime, 150 ns). This work offers the important physical insight into the charge carrier dynamics of low-toxicity QDs which have the desired optical properties for optoelectronic applications.

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InP-Based Quantum Dot Light-Emitting Diode with a Blended Emissive Layer

Cited by 54 publications

References 42 publications

Nondestructive Direct Photolithography for Patterning Quantum Dot Films by Atomic Layer Deposition of ZnO

Nondestructive Direct Photolithography for Patterning Quantum Dot Films by Atomic Layer Deposition of ZnO

High Performance InP‐based Quantum Dot Light‐Emitting Diodes via the Suppression of Field‐Enhanced Electron Delocalization

Effects of Interfacial Oxidative Layer Removal on Charge Carrier Recombination Dynamics in InP/ZnSe_xS_1–x Core/Shell Quantum Dots

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InP-Based Quantum Dot Light-Emitting Diode with a Blended Emissive Layer

Cited by 54 publications

References 42 publications

Nondestructive Direct Photolithography for Patterning Quantum Dot Films by Atomic Layer Deposition of ZnO

Nondestructive Direct Photolithography for Patterning Quantum Dot Films by Atomic Layer Deposition of ZnO

High Performance InP‐based Quantum Dot Light‐Emitting Diodes via the Suppression of Field‐Enhanced Electron Delocalization

Effects of Interfacial Oxidative Layer Removal on Charge Carrier Recombination Dynamics in InP/ZnSexS1–x Core/Shell Quantum Dots

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Effects of Interfacial Oxidative Layer Removal on Charge Carrier Recombination Dynamics in InP/ZnSe_xS_1–x Core/Shell Quantum Dots