The Experts below are selected from a list of 81393 Experts worldwide ranked by ideXlab platform
Frank W. Wise - One of the best experts on this subject based on the ideXlab platform.
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bright infrared quantum dot light emitting diodes through inter dot spacing control
Nature Nanotechnology, 2012Co-Authors: Joshua J. Choi, Byung-ryool Hyun, Adam C. Bartnik, David Stachnik, Tobias Hanrath, George G. Malliaras, Frank W. WiseAbstract:This material is based on work supported by the National Science Foundation (NSF, grant no. EEC-0646547) and by the New York State Foundation for Science, Technology and Innovation (NYSTAR). J.J.C. and D.S. acknowledge support from the Cornell Center for Materials Research with funding from IGERT: a Graduate Traineeship in Nanoscale Control of Surfaces and Interfaces (DGE-0654193) of the NSF. This publication is based on work supported in part by an award (no. KUS-C1-018-02) made by King Abdullah University of Science and Technology (KAUST). GISAXS measurements were conducted at Cornell High Energy Synchrotron Source (CHESS) and the authors thank D.-M. Smilgies for calibration of the beam line set-up.
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Bright infrared quantum-dot light-emitting diodes through inter-dot spacing control
Nature Nanotechnology, 2012Co-Authors: Liangfeng Sun, Byung-ryool Hyun, Adam C. Bartnik, Joshua J. Choi, David Stachnik, Tobias Hanrath, George G. Malliaras, Frank W. WiseAbstract:Infrared light-emitting diodes are currently fabricated from direct-gap semiconductors using epitaxy, which makes them expensive and difficult to integrate with other materials. Light-emitting diodes based on colloidal semiconductor quantum dots, on the other hand, can be solution-processed at low cost, and can be directly integrated with silicon. However, so far, exciton dissociation and recombination have not been well controlled in these devices, and this has limited their performance. Here, by tuning the distance between adjacent PbS quantum dots, we fabricate thin-film quantum-dot light-emitting diodes that operate at infrared wavelengths with radiances (6.4 W sr(-1) m(-2)) eight times higher and external quantum efficiencies (2.0%) two times higher than the highest values previously reported. The distance between adjacent dots is tuned over a range of 1.3 nm by varying the lengths of the linker molecules from three to eight CH(2) groups, which allows us to achieve the optimum balance between charge injection and radiative exciton recombination. The electroluminescent powers of the best devices are comparable to those produced by commercial InGaAsP light-emitting diodes. By varying the size of the quantum dots, we can tune the emission wavelengths between 800 and 1,850 nm.
Furong Zhu - One of the best experts on this subject based on the ideXlab platform.
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Morphology control towards bright and stable inorganic halide perovskite light-emitting diodes
Journal of Materials Chemistry C, 2018Co-Authors: Fangming Jin, Bei Chu, Wenlian Li, Zisheng Su, Haifeng Zhao, Bo Zhao, Furong ZhuAbstract:The effect of morphology control on the performance of inorganic cesium lead halide based green perovskite light-emitting diodes (PeLEDs) was analyzed. The PeLEDs were prepared using two different formulation approaches:...
George G. Malliaras - One of the best experts on this subject based on the ideXlab platform.
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bright infrared quantum dot light emitting diodes through inter dot spacing control
Nature Nanotechnology, 2012Co-Authors: Joshua J. Choi, Byung-ryool Hyun, Adam C. Bartnik, David Stachnik, Tobias Hanrath, George G. Malliaras, Frank W. WiseAbstract:This material is based on work supported by the National Science Foundation (NSF, grant no. EEC-0646547) and by the New York State Foundation for Science, Technology and Innovation (NYSTAR). J.J.C. and D.S. acknowledge support from the Cornell Center for Materials Research with funding from IGERT: a Graduate Traineeship in Nanoscale Control of Surfaces and Interfaces (DGE-0654193) of the NSF. This publication is based on work supported in part by an award (no. KUS-C1-018-02) made by King Abdullah University of Science and Technology (KAUST). GISAXS measurements were conducted at Cornell High Energy Synchrotron Source (CHESS) and the authors thank D.-M. Smilgies for calibration of the beam line set-up.
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Bright infrared quantum-dot light-emitting diodes through inter-dot spacing control
Nature Nanotechnology, 2012Co-Authors: Liangfeng Sun, Byung-ryool Hyun, Adam C. Bartnik, Joshua J. Choi, David Stachnik, Tobias Hanrath, George G. Malliaras, Frank W. WiseAbstract:Infrared light-emitting diodes are currently fabricated from direct-gap semiconductors using epitaxy, which makes them expensive and difficult to integrate with other materials. Light-emitting diodes based on colloidal semiconductor quantum dots, on the other hand, can be solution-processed at low cost, and can be directly integrated with silicon. However, so far, exciton dissociation and recombination have not been well controlled in these devices, and this has limited their performance. Here, by tuning the distance between adjacent PbS quantum dots, we fabricate thin-film quantum-dot light-emitting diodes that operate at infrared wavelengths with radiances (6.4 W sr(-1) m(-2)) eight times higher and external quantum efficiencies (2.0%) two times higher than the highest values previously reported. The distance between adjacent dots is tuned over a range of 1.3 nm by varying the lengths of the linker molecules from three to eight CH(2) groups, which allows us to achieve the optimum balance between charge injection and radiative exciton recombination. The electroluminescent powers of the best devices are comparable to those produced by commercial InGaAsP light-emitting diodes. By varying the size of the quantum dots, we can tune the emission wavelengths between 800 and 1,850 nm.
Brandon R. Sutherland - One of the best experts on this subject based on the ideXlab platform.
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Ultra-bright and highly efficient inorganic based perovskite light-emitting diodes
Nature Communications, 2017Co-Authors: Liuqi Zhang, Mingyang Wei, Zhigang Yin, Yang Michael Yang, Hairen Tan, Xingwang Zhang, Pengyang Wang, Xiaolei Yang, Qi Jiang, Brandon R. SutherlandAbstract:Hybrid organic-inorganic perovskites are garnering attention for light emitting diode (LED) applications. Employing a thin hydrophilic insulating polymer, Zhang et al. report LEDs exhibiting a brightness of 91,000 cd m−2 and external quantum efficiency of 10.4% using a mixed-cation perovskite.
Ho Seong Jang - One of the best experts on this subject based on the ideXlab platform.
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Highly bright yellow-green-emitting CuInS2 colloidal quantum dots with core/shell/shell architecture for white light-emitting diodes
ACS Applied Materials and Interfaces, 2015Co-Authors: Sang-hyun Park, Ara Hong, Kwangyeol Lee, Jong-hoon Kim, Heesun Yang, Ho Seong JangAbstract:In this study, we report bright yellow-green-emitting CuInS2 (CIS)-based quantum dots (QDs) and two-band white light-emitting diodes (LEDs) using them. To achieve high quantum efficiency (QE) of yellow-green-emitting CIS QDs, core/shell/shell strategy was introduced to high quality CIS cores (QE = 31.7%) synthesized by using metal-oleate precursors and 1-dodecanethiol. The CIS/ZnS/ZnS QDs showed a high QE of 80.0% and a peak wavelength of 559 nm under the excitation of 450 nm, which is well matched with dominant wavelength of blue LEDs. The formation of core/shell/shell structure was confirmed by X-ray diffraction, transmission electron microscopy, and inductively coupled plasma-optical emission spectroscopy analyses. Intense and broad yellow-green emission band of the CIS/ZnS/ZnS is beneficial for bright two-band white light. When the CIS/ZnS/ZnS was coated on the blue LEDs, the fabricated white LED showed bright natural white light (luminous efficacy (ηL) = 80.3 lm·W(-1), color rendering index (Ra) = 73, correlated color temperature (Tc) = 6140 K). The QD-white LED package showed a high light conversion efficiency of 72.6%. In addition, the CIS/ZnS/ZnS-converted white LED showed relatively stable white light against the variation of forward bias currents of 20-150 mA [color coordinates (x, y) = (0.3320-0.3207, 0.2997-0.2867), Ra = 70-72, Tc = 5497-6375 K].
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bright dual mode green emission from selective set of dopant ions in β na y gd f 4 yb er β nagdf 4 ce tb core shell nanocrystals
Optics Express, 2012Co-Authors: Ho Seong JangAbstract:Bright dual-mode green-emitting core/shell nanoparticles (NPs) were synthesized by doping selective set of lanthanide ions. Up-conversion (UC) green-emitting β-NaY0.2Gd0.6F4:Yb0.18,Er0.02 NPs (8.3 nm) were used as core material. Bright down-conversion (DC) green-emitting β-NaGd0.8F4:Ce0.15,Tb0.05 NPs showed ca. 31 times higher photoluminescence (PL) intensity than β-NaGdF4:Tb NPs and they were served as shell material with their excellent PL properties. The UC/DC core/shell NPs showed bright green light under excitations of 980 nm near infrared (NIR) light and 254 nm ultraviolet (UV) light, respectively. The UC/DC core/shell NPs showed ca. 11 times higher UC PL intensity than core UCNPs. Consequently, the core/shell NPs doped with selective set of lanthanide ions showed bright dual-mode green emission under excitations of NIR light and UV light, indicating that they are promising for application to optical imaging.
