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Proceedings Paper

Warm white LED light by frequency down-conversion of mixed yellow and red Lumogen
Author(s): Mauro Mosca; Fulvio Caruso; Leandro Zambito; Biagio Seminara; Roberto Macaluso; Claudio Calì; Eric Feltin
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Paper Abstract

This work reports on the benefits and promising opportunities offered by white LED hybrid technology, based on a mixing perylene-based dyes in order to obtain a warm white light for frequency-down conversion. In a standard Ce:YAG-based white LED, the white light appears cold due to the weakness of red wavelength components in the emission spectrum. In order to obtain a warmer white, one possible solution is to add a red phosphor to the yellow one to move the chromatic coordinates properly, though the luminous efficiency drastically decreases due to the increased light absorption of the coating layer. It is generally believed that the low efficiency of warm white LEDs is the main issue today for LED-based lighting. Using photoluminescence of Lumogen® F Yellow 083, a perylene-based polymer dye commercialized by BASF, and adding a small quantity of another perylene-based dye, Lumogen® F Red 305 (BASF), we obtained high-efficiency warm white LEDs by yellow and red conversion from a standard 450 nm GaN/InGaN royal blue LED. Different weight proportions of dyes were dissolved in solutions with equal amounts of poly-methyl-methacrylate (PMMA) in ethyl acetate, then the LEDs were dip-coated in each solution and optically characterized. Record values of 8.03 lm of luminous flux and 116.11 lm/W of optical efficiency were achieved. Finally, the effects of both driving current, and pump wavelength on LED performances – such as chromatic coordinates, correlated color temperature, color rendering index (CRI), and optical efficiency – were investigated.

Paper Details

Date Published: 22 May 2013
PDF: 10 pages
Proc. SPIE 8767, Integrated Photonics: Materials, Devices, and Applications II, 87670L (22 May 2013); doi: 10.1117/12.2017274
Show Author Affiliations
Mauro Mosca, Univ. degli Studi di Palermo (Italy)
Fulvio Caruso, Univ. degli studi di Palermo (Italy)
Leandro Zambito, Univ. degli studi di Palermo (Italy)
Biagio Seminara, Univ. degli Studi di Palermo (Italy)
Roberto Macaluso, Univ. degli studi di Palermo (Italy)
Claudio Calì, Univ. degli studi di Palermo (Italy)
Eric Feltin, Novagan, Sàrl (Switzerland)

Published in SPIE Proceedings Vol. 8767:
Integrated Photonics: Materials, Devices, and Applications II
Jean-Marc Fédéli; Laurent Vivien; Meint K. Smit, Editor(s)

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