The Experts below are selected from a list of 194523 Experts worldwide ranked by ideXlab platform

Kookheon Char - One of the best experts on this subject based on the ideXlab platform.

  • push pull design of bis tridentate ruthenium ii polypyridine chromophores as deep red light emitters in light emitting electrochemical cells
    European Journal of Organic Chemistry, 2014
    Co-Authors: Aaron Breivogel, Myeongjin Park, Kookheon Char, Donggu Lee, Stefanie Klassen, Angelika Kuhnle, Changhee Lee, Katja Heinze
    Abstract:

    Light-emitting electrochemical cells (LECs) with a simple Device Structure were prepared by using heteroleptic bis(tridentate) ruthenium(II) complexes [1](PF6)(2)-[3](PF6)(2) as emitters. The push-pull substitution shifts the emission energy to low energy, into the NIR region. The Devices emit deep red light up to a maximum emission wavelength of 755 nm [CIE (International Commission on Illumination) coordinates: x = 0.731, y = 0.269 for [3](PF6)(2)], which, to the best of our knowledge, is the lowest emission energy for LECs containing bis(tridentate) ruthenium(II) complexes. A Device Structure of ITO/PEDOT:PSS/ruthenium(II) complex/Ag was used, and the thickness of the emitting layer was measured by AFM [ITO: indium tin oxide, PEDOT: poly(3,4-ethylenedioxythiophene), PSS: poly(styrenesulfonate), AFM: atomic force microscopy]. To enhance the external quantum efficiency (EQE), cells were fabricated with and without poly(methyl methacrylate) (PMMA) as additive in the emitting layer.

  • bright and efficient full color colloidal quantum dot light emitting diodes using an inverted Device Structure
    Nano Letters, 2013
    Co-Authors: Jeonghun Kwak, Insun Park, Myeongjin Park, Do Y Yoon, Kookheon Char
    Abstract:

    We report highly bright and efficient red, green, and blue quantum dot (QD) based light-emitting diodes (QLEDs) by using an inverted Device Structure with solution-processed ZnO nanoparticles as the electron injection layer and by optimizing energy levels with the organic hole transport layer.

  • bright and efficient full color colloidal quantum dot light emitting diodes using an inverted Device Structure
    Nano Letters, 2012
    Co-Authors: Jeonghun Kwak, Insun Park, Myeongjin Park, Do Y Yoon, Kookheon Char
    Abstract:

    We report highly bright and efficient inverted Structure quantum dot (QD) based light-emitting diodes (QLEDs) by using solution-processed ZnO nanoparticles as the electron injection/transport layer and by optimizing energy levels with the organic hole transport layer. We have successfully demonstrated highly bright red, green, and blue QLEDs showing maximum luminances up to 23 040, 218 800, and 2250 cd/m2, and external quantum efficiencies of 7.3, 5.8, and 1.7%, respectively. It is also noticeable that they showed turn-on voltages as low as the bandgap energy of each QD and long operational lifetime, mainly attributed to the direct exciton recombination within QDs through the inverted Device Structure. These results signify a remarkable progress in QLEDs and offer a practicable platform for the realization of QD-based full-color displays and lightings.

Jeonghun Kwak - One of the best experts on this subject based on the ideXlab platform.

Myeongjin Park - One of the best experts on this subject based on the ideXlab platform.

  • push pull design of bis tridentate ruthenium ii polypyridine chromophores as deep red light emitters in light emitting electrochemical cells
    European Journal of Organic Chemistry, 2014
    Co-Authors: Aaron Breivogel, Myeongjin Park, Kookheon Char, Donggu Lee, Stefanie Klassen, Angelika Kuhnle, Changhee Lee, Katja Heinze
    Abstract:

    Light-emitting electrochemical cells (LECs) with a simple Device Structure were prepared by using heteroleptic bis(tridentate) ruthenium(II) complexes [1](PF6)(2)-[3](PF6)(2) as emitters. The push-pull substitution shifts the emission energy to low energy, into the NIR region. The Devices emit deep red light up to a maximum emission wavelength of 755 nm [CIE (International Commission on Illumination) coordinates: x = 0.731, y = 0.269 for [3](PF6)(2)], which, to the best of our knowledge, is the lowest emission energy for LECs containing bis(tridentate) ruthenium(II) complexes. A Device Structure of ITO/PEDOT:PSS/ruthenium(II) complex/Ag was used, and the thickness of the emitting layer was measured by AFM [ITO: indium tin oxide, PEDOT: poly(3,4-ethylenedioxythiophene), PSS: poly(styrenesulfonate), AFM: atomic force microscopy]. To enhance the external quantum efficiency (EQE), cells were fabricated with and without poly(methyl methacrylate) (PMMA) as additive in the emitting layer.

  • bright and efficient full color colloidal quantum dot light emitting diodes using an inverted Device Structure
    Nano Letters, 2013
    Co-Authors: Jeonghun Kwak, Insun Park, Myeongjin Park, Do Y Yoon, Kookheon Char
    Abstract:

    We report highly bright and efficient red, green, and blue quantum dot (QD) based light-emitting diodes (QLEDs) by using an inverted Device Structure with solution-processed ZnO nanoparticles as the electron injection layer and by optimizing energy levels with the organic hole transport layer.

  • bright and efficient full color colloidal quantum dot light emitting diodes using an inverted Device Structure
    Nano Letters, 2012
    Co-Authors: Jeonghun Kwak, Insun Park, Myeongjin Park, Do Y Yoon, Kookheon Char
    Abstract:

    We report highly bright and efficient inverted Structure quantum dot (QD) based light-emitting diodes (QLEDs) by using solution-processed ZnO nanoparticles as the electron injection/transport layer and by optimizing energy levels with the organic hole transport layer. We have successfully demonstrated highly bright red, green, and blue QLEDs showing maximum luminances up to 23 040, 218 800, and 2250 cd/m2, and external quantum efficiencies of 7.3, 5.8, and 1.7%, respectively. It is also noticeable that they showed turn-on voltages as low as the bandgap energy of each QD and long operational lifetime, mainly attributed to the direct exciton recombination within QDs through the inverted Device Structure. These results signify a remarkable progress in QLEDs and offer a practicable platform for the realization of QD-based full-color displays and lightings.

Insun Park - One of the best experts on this subject based on the ideXlab platform.

Do Y Yoon - One of the best experts on this subject based on the ideXlab platform.