Wavelength dependent color conversion of CdSe/ZnS core/shell nanocrystals for white LEDs
Author
Nizamoğlu, Sedat
Demir, Hilmi Volkan
Date
2009Source Title
2009 IEEE LEOS Annual Meeting Conference Proceedings
Print ISSN
1092-8081
Publisher
IEEE
Pages
280 - 281
Language
English
Type
Conference PaperItem Usage Stats
136
views
views
95
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downloads
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 lightingCdSe/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/11693/28600Published Version (Please cite this version)
http://dx.doi.org/10.1109/LEOS.2009.5343274Collections
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