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Ce 3+ ‐Sensitized Tm 3+ /Mn 2+ ‐Doped NaYF 4 Colloidal Nanocrystals: Intense Cool White Light from a Phosphor‐Coated UV LED
Author(s) -
Adusumalli Venkata N. K. B.,
Koppisetti Heramba V. S. R. M.,
Mahalingam Venkataramanan
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201704156
Subject(s) - phosphor , materials science , ion , nanocrystal , doping , light emitting diode , analytical chemistry (journal) , dopant , luminescence , photon upconversion , absorption (acoustics) , optoelectronics , nanotechnology , chemistry , organic chemistry , chromatography , composite material
Colloidal NaYF 4 :Ce 3+ /Tm 3+ /Mn 2+ nanocrystals found to be an efficient single component phosphor to produce intense white light. The use of Mn 2+ ions instead of green‐ and red‐emitting Ln 3+ ions is interesting as the later are expensive and less abundant. The single band blue emission of Tm 3+ ions was combined with the broadband green–yellow emission of Mn 2+ ions to produce strong white light emission using Ce 3+ ions as excitation source. Interestingly, there is hardly any re‐absorption of the blue emission by Mn 2+ ions and the spectrum matches the commercial Ce 3+ ‐doped yttrium aluminium garnet (YAG) phosphor coated over a blue LED. In addition, we have successfully incorporated the colloidal nanocrystals into a polymer matrix to make a nanocomposite as well as transparent films without altering the optical properties of the nanocrystals. The colloidal nanocomposite was coated over a UV LED to fabricate white LEDs. Finally, when the concentration of the dopant (Mn 2+ ) ions was tuned the correlated color temperature (CCT) values varied between cool white light and daylight region.