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      Wavelength dependent color conversion of CdSe/ZnS core/shell nanocrystals for white LEDs

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      Author
      Nizamoğlu, Sedat
      Demir, Hilmi Volkan
      Date
      2009
      Source Title
      2009 IEEE LEOS Annual Meeting Conference Proceedings
      Print ISSN
      1092-8081
      Publisher
      IEEE
      Pages
      280 - 281
      Language
      English
      Type
      Conference Paper
      Item Usage Stats
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      Abstract
      Nanocrystals (NCs) provide narrow emission spectrum that can be conveniently tuned using quantum size effect. This ability to adjust and control emission spectrum of NCs makes them strong candidates for use in white color conversion light emitting diodes. For example, they are possibly be used for solid state lighting applications including indoor lighting, architectural lighting and scotopic street lighting, where spectrally tuned color conversion is necessary. In device research CdSe/ZnS core/shell nanocrystals are the most commonly used ones because of their good electronic isolation coming from ZnS shells and the resulting high quantum efficiency (QE) (i.e., >50% in solution) [1]. However, when these nanocrystals are integrated into the solid film, e.g., for white light generation, their in-film QE undesirably drops (despite their high QE in solution). Hence, this adversely affects the overall efficiency of the integrating devices that incorporate these NCs [2]. There have been various studies to understand the in-film optical properties of CdSe/ZnS core/shell NCs [3-5]. However, their spectrally resolved in-film quantum efficiency (i.e., the ratio of the number of photons emitted by the nanocrystal film to the number of photons absorbed in the nanocrystal film) and their photon conversion efficiency (i.e., the ratio of the number of photons emitted by the nanocrystal film to the number of photons incident to the nanocrystal film) have not been investigated in these previous studies. © 2009 IEEE.
      Keywords
      Architectural lighting
      CdSe/ZnS core/shell
      Color conversions
      Emission spectrums
      High quantum efficiency
      Nanocrystal films
      Overall efficiency
      Photon conversion efficiencies
      Quantum size effects
      Solid films
      Solid-state lighting application
      Tuned color
      White color
      White LED
      White-light generation
      Color
      Conversion efficiency
      Emission spectroscopy
      Light
      Light emitting diodes
      Nanocrystals
      Photons
      Semiconductor quantum dots
      Street lighting
      Zinc sulfide
      Quantum efficiency
      Permalink
      http://hdl.handle.net/11693/28600
      Published Version (Please cite this version)
      http://dx.doi.org/10.1109/LEOS.2009.5343274
      Collections
      • Department of Electrical and Electronics Engineering 3524
      • Department of Physics 2299
      • Institute of Materials Science and Nanotechnology (UNAM) 1775
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