Bright, multicoloured light-emitting diodes based on quantum dots

Sun, Qingjiang; Wang, Y. Andrew; Li, Lin Song; Wang, Daoyuan; Tao, Zhu; Xu, Jian; Yang, Chunhe; Li, Yongfang

doi:10.1038/nphoton.2007.226

Cited by 1,075 publications

(798 citation statements)

References 29 publications

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“…Figure 13 shows the calculated emission intensity as a function of various Alq 3 layer thicknesses. Obviously, the emission intensity is linearly increased to a certain thickness of the ETL (∼ 120 nm), in a good agreement with the previously reported experimental results for QD-LEDs [37]). And with further increasing the ETL layer thickness the emission intensity starts to decrease.…”

Section: Resultssupporting

confidence: 92%

Electromagnetic Modeling of Outcoupling Efficiency and Light Emission in Near-Infrared Quantum Dot Light Emitting Devices

Farghal¹,

Wageh²,

Elazm³

2010

PIER B

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Abstract-We report an analytical exciton emission model based on Green function for simulating the radiation characteristics of nearinfrared Quantum Dot-light emitting devices (QD-LEDs). In this model the internally emitted light can be classified into the following modes: Substrate, indium tin oxide (ITO)/organic waveguided, surface plasmonic modes, and external emitted mode. We investigate the influence of the thickness of different layers and the distance between the emitting center and the cathode metal on the emitted power distribution among these modes. In addition, we study the angular radiation profile for the externally emitted radiation and substrate waveguided mode in comparison with Lambertian radiation profile. We show the change of the thickness of the different layers, and the positions of the emitting centers are critical to the optical performance of the device. The optimization of optical performance through device geometry increases the outcoupling efficiency more than five times.

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Section: Resultssupporting

confidence: 92%

Electromagnetic Modeling of Outcoupling Efficiency and Light Emission in Near-Infrared Quantum Dot Light Emitting Devices

Farghal¹,

Wageh²,

Elazm³

2010

PIER B

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“…So, the QDs have great potential applications in thin-film light-emitting diodes (LEDs), solar cells, lasers, optical amplifier media, biology labels, immunoassay etc. [3][4][5][6]. The high surface to volume ratio of QDs means that the surface properties significantly influence their structural and optical properties, because of the large surface area and possible presence of surface states caused by uncoordinated atoms that act as quencher of the * E-mail: qyq0500@163.com luminescence.…”

Section: Introductionmentioning

confidence: 99%

Investigation on photoluminescence quenching of CdSe/ZnS quantum dots by organic charge transporting materials

Zhang

et al. 2015

Materials Science-Poland

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The effect of different organic charge transporting materials on the photoluminescence of CdSe/ZnS core/shell quantum dots has been studied by means of steady-state and time-resolved photoluminescence spectroscopy. With an increase in concentration of the organic charge transporting material in the quantum dots solutions, the photoluminescence intensity of CdSe/ZnS quantum dots was quenched greatly and the fluorescence lifetime was shortened gradually. The quenching efficiency of CdSe/ZnS core/shell quantum dots decreased with increasing the oxidation potential of organic charge transporting materials. Based on the analysis, two pathways in the photoluminescence quenching process have been defined: static quenching and dynamic quenching. The dynamic quenching is correlated with hole transporting from quantum dots to the charge transporting materials.

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“…In the first device layout, a thin QD layer is sandwiched between a hole and electron injection layer such that excitons are formed directly in the QD layer. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] In the second layout, the active layer consists of a blend of QDs dispersed in a polymer [29][30][31][32][33][34][35][36][37][38][39] or small molecule matrix. 40,41 The QDs in this composite material serve as emissive traps for ͑migrating͒ excitons that are generated in the polymer matrix by charge carrier recombination.…”

Section: Introductionmentioning

confidence: 99%

Energy transfer in hybrid quantum dot light-emitting diodes

Chin

Hikmet

Janssen

2008

Journal of Applied Physics

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Energy transfer in a host-guest system consisting of a blue-emitting poly͑2,7-spirofluorene͒ ͑PSF͒ donor and red-emitting CdSe/ ZnS core shell quantum dots ͑QDs͒ as acceptor is investigated in solid films, using time-resolved optical spectroscopy, and in electroluminescent diodes. In the QD:PSF composite films, the Förster radius for energy transfer is found to be 4 -6 nm. In electroluminescent devices lacking an electron transport layer, the electroluminescence ͑EL͒ spectrum of the QD:PSF polymer composite is similar to the photoluminescence ͑PL͒, giving evidence for energy transfer from PSF to the QDs. The addition of an electron transport layer between the emitting layer and the cathode results in a significant change in the EL spectrum and a considerable improved device performance, providing almost pure monochromatic emission at 630 nm with a luminance efficiency of 0.32 cd/ A. The change in spectrum signifies that the electron transport layer changes the dominant pathway for QD emission from energy transfer from the polymer host to direct electron-hole recombination on the QDs.

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Bright, multicoloured light-emitting diodes based on quantum dots

Cited by 1,075 publications

References 29 publications

Electromagnetic Modeling of Outcoupling Efficiency and Light Emission in Near-Infrared Quantum Dot Light Emitting Devices

Electromagnetic Modeling of Outcoupling Efficiency and Light Emission in Near-Infrared Quantum Dot Light Emitting Devices

Investigation on photoluminescence quenching of CdSe/ZnS quantum dots by organic charge transporting materials

Energy transfer in hybrid quantum dot light-emitting diodes

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