Mishra, Savvi and Rajeswari, R. and Vijayan, N. and Shanker, V. and Dalai, M. K. and Jayasankar, C. K. and Babu, S. Surendra and Haranath, D. (2013) Probing the structure, morphology and multifold blue absorption of a new red-emitting nanophosphor for LEDs. Journal of Materials Chemistry C, 1. pp. 5849-5855. ISSN 2050-7526

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Abstract

There has been a stringent demand for blue (similar to 450 to 470 nm) absorbing and red (similar to 611 nm) emitting material systems in phosphor converted white light emitting diodes (WLEDs) available in the market. The conventionally used red-emitting Y2O3:Eu3+ phosphor has negligible absorption for blue light produced by GaInN based LED chips. To address this issue, a new red-emitting Gd2CaZnO5:Eu3+ (GCZO:Eu3+) nanophosphor system having exceptionally strong absorption for blue (similar to 465 nm) and significant red (similar to 611 nm) photoluminescence is presented. This is attributed to a dominant f-f transition (D-5(0) -> F-7(2)) of Eu3+ ions, arising due to an efficient energy transfer from the Gd3+ sites of the host lattice to Eu3+ ions. The external quantum yield (QY) measured at 465 nm absorption and 611 nm emission revealed that the GCZO: Eu3+ nanophosphor has better QY of 23% as compared to commercial Y2O3:Eu3+, which is <1%. X-ray diffraction and microscopy observations showed the nanocrystalline nature and slightly elongated morphology of the sample, respectively. While the energy dispersive X-ray analysis identified the chemical constituents of the GCZO: Eu3+ nanophosphor, the color overlay imaging confirmed the substitution of Eu3+ for Gd3+ ions. As seen from the QY statistics it is highly anticipated that the multifold absorption at similar to 465 nm would certainly improve the color rendering properties of existing WLEDs.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/s Royal Society of Chemistry.
Subjects:	Materials Science Applied Physics/Condensed Matter
Divisions:	UNSPECIFIED
Depositing User:	Users 27 not found.
Date Deposited:	03 Jul 2020 10:12
Last Modified:	03 Jul 2020 10:12
URI:	http://npl.csircentral.net/id/eprint/3086

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