InP/ZnS/ZnS Core/Shell Blue Quantum Dots for Efficient Light‐Emitting Diodes

Zhang, Wenda; Ding, Shihao; Zhuang, Weidong; Wu, Dan; Liu, Pai; Qu, Xiangwei; Liu, Haochen; Yang, Hongcheng; Wu, Zhenghui; Wang, Kai; Sun, Xiao Wei

doi:10.1002/adfm.202005303

Cited by 125 publications

(113 citation statements)

References 30 publications

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“…The relative position of the energy levels of the two semiconductors is still poorly understood in spite of their extensive studies [ 31 ]. The approximate location of some of those energy levels is given in [ 34 ]. One can assume that ZnS has the ground state energy 7.0 eV.…”

Section: Discussionmentioning

confidence: 99%

Nonlinear Optical Characterization of InP@ZnS Core-Shell Colloidal Quantum Dots Using 532 nm, 10 ns Pulses

et al. 2021

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InP@ZnS core-shell colloidal quantum dots (CQDs) were synthesized and characterized using the z-scan technique. The nonlinear refraction and nonlinear absorption coefficients (γ = −2 × 10−12 cm2 W−1, β = 4 × 10−8 cm W−1) of these CQDs were determined using 10 ns, 532 nm pulses. The saturable absorption (β = −1.4 × 10−9 cm W−1, Isat = 3.7 × 108 W cm−2) in the 3.5 nm CQDs dominated at small intensities of the probe pulses (I ≤ 7 × 107 W cm−2) followed by reverse saturable absorption at higher laser intensities. We report the optical limiting studies using these CQDs showing the suppression of propagated nanosecond radiation in the intensity range of 8 × 107–2 × 109 W cm−2. The role of nonlinear scattering is considered using off-axis z-scan scheme, which demonstrated the insignificant role of this process along the whole range of used intensities of 532 nm pulses. We discuss the thermal nature of the negative nonlinear refraction in the studied species.

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Section: Discussionmentioning

confidence: 99%

Nonlinear Optical Characterization of InP@ZnS Core-Shell Colloidal Quantum Dots Using 532 nm, 10 ns Pulses

et al. 2021

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“…These two drawbacks may be addressed through a controlled synthesis of InP/ZnSe/ZnS core/shell system. 19,20 Stoichiometric control within both the core and shell regions achieved by purification of the precursors between the different shell growth stages, was found to result in InP/ZnSe/ZnS nanocrystals with a high quantum yield of 93% and QD-LED external quantum efficiency (EQE) of 12.2% (Figure 5b). 20 A follow-up study then demonstrated the achievement of highly spherical and symmetrical core/shell structure nanocrystals that further increased the stability and efficiency of the system.…”

Section: Rohs Compatible Colloidal Quantum Materialsmentioning

confidence: 99%

Material Challenges for Colloidal Quantum Nanostructures in Next Generation Displays

Panfil¹,

Oded²,

Waiskopf³

et al. 2020

ACM

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The recent technological advancements have greatly improved the quality and resolution of displays. Yet, issues like full-color gamut representation and the long-lasting durability of the color emitters require further progression. Colloidal quantum dots manifest an inherent narrow spectral emission with optical stability, combined with various chemical processability options which will allow for their integration in display applications. Apart from their numerous advantages, they also present unique opportunities for the next technological leaps in the field.

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“…Micro-LEDs have the advantages of high contrast, low power consumption, long life, and fast response time, but they can be improved further [ 35 ]. Zhang et al proposed the use of pure blue double-shell InP/(ZnS) QDs with an emission wavelength of 468 nm and a quantum yield of 45%, and they managed to increase EQE by 2.8 times [ 36 ]. Yang Li et al proposed the application of microfluidic technology combined with a red–green perovskite QDs color conversion layer for use in micro-LEDs displays and achieved a wide color gamut (NTSC) of 131% [ 37 ].…”

Section: Introductionmentioning

confidence: 99%

Use of Recycling-Reflection Color-Purity Enhancement Film to Improve Color Purity of Full-Color Micro-LEDs

2022

Nanoscale Res Lett

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A common full-color method involves combining micro-light-emitting diodes (LEDs) chips with color conversion materials such as quantum dots (QDs) to achieve full color. However, during color conversion between micro-LEDs and QDs, QDs cannot completely absorb incident wavelengths cause the emission wavelengths that including incident wavelengths and converted wavelength through QDs, which compromises color purity. The present paper proposes the use of a recycling-reflection color-purity-enhancement film (RCPEF) to reflect the incident wavelength multiple times and, consequently, prevent wavelength mixing after QDs conversion. This RCPEF only allows the light of a specific wavelength to pass through it, exciting blue light is reflected back to the red and green QDs layer. The prototype experiment indicated that with an excitation light source wavelength of 445.5 nm, the use of green QDs and RCPEFs increased color purity from 77.2% to 97.49% and light conversion efficiency by 1.97 times and the use of red QDs and RCPEFs increased color purity to 94.68% and light conversion efficiency by 1.46 times. Thus, high efficiency and color purity were achieved for micro-LEDs displays. Graphical Abstract

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InP/ZnS/ZnS Core/Shell Blue Quantum Dots for Efficient Light‐Emitting Diodes

Cited by 125 publications

References 30 publications

Nonlinear Optical Characterization of InP@ZnS Core-Shell Colloidal Quantum Dots Using 532 nm, 10 ns Pulses

Nonlinear Optical Characterization of InP@ZnS Core-Shell Colloidal Quantum Dots Using 532 nm, 10 ns Pulses

Material Challenges for Colloidal Quantum Nanostructures in Next Generation Displays

Use of Recycling-Reflection Color-Purity Enhancement Film to Improve Color Purity of Full-Color Micro-LEDs

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