Cool to warm white light emission from hybrid inorganic/organic light-emitting diodes

Taylor-Shaw, E., Angioni, E. , Findlay, N. J. , Breig, B., Inigo, A. R., Bruckbauer, J., Wallis, D. J., Skabara, P. J. and Martin, R. W. (2016) Cool to warm white light emission from hybrid inorganic/organic light-emitting diodes. Journal of Materials Chemistry C, 4(48), pp. 11499-11507. (doi:10.1039/C6TC03585J)

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Abstract

The synthesis and characterisation of two novel organic down-converting molecules is disclosed, together with their performance as functional colour-converters in combination with inorganic blue light-emitting diodes (LEDs). Each molecule contains two fluorene-triphenylamine arms, connected to either a benzothiadiazole or bisbenzothiadiazole core. These molecules have been selected on the basis that they are free from absorption bands in the green region of the visible spectrum to maximise their performance and offer improvements compared with previous BODIPY-containing analogues. The inorganic InGaN/GaN LED emits at 444 nm, overlying the absorption of each of the organic molecules. The combination of the blue (inorganic) and yellow (organic) emission is shown to produce reasonable quality, white light-emitting hybrid devices for both down-converter molecules. Cool to warm white light is achieved for both molecules by increasing the concentration. An optimum colour rendering index (CRI) value of 66 is obtained for the mono-benzothiadiazole molecule. Also a high blue-to-white efficacy (defined as white luminous flux (lm)/blue radiant flux (W)) of 368 lm W−1 is achieved, superseding the current phosphor converters of 200–300 lm W−1. A comparison of these down-converting molecules to the older generation BODIPY-containing molecules is also provided.

Item Type:Articles
Additional Information:The authors would like to thank UK EPSRC (Grant No. EP/I012591/1 ‘‘Lighting the Future’’ and EP/L016982/1 ‘‘Next generation white LEDs using hybrid inorganic/organic semiconductor nanostructures for general illumination and wireless communication’’) for financial support. DJW received funding through EPSRC’s Manufacturing Fellowship in Gallium Nitride (EP/N01202X/1). PJS thanks the Royal Society for a Wolfson Research Merit Award.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Skabara, Professor Peter and Findlay, Mr Neil and Angioni, Mr Enrico
Authors: Taylor-Shaw, E., Angioni, E., Findlay, N. J., Breig, B., Inigo, A. R., Bruckbauer, J., Wallis, D. J., Skabara, P. J., and Martin, R. W.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Journal of Materials Chemistry C
Publisher:Royal Society of Chemistry
ISSN:2050-7526
ISSN (Online):2050-7534
Copyright Holders:Copyright © 2016 The Royal Society of Chemistry
First Published:First published in Journal of Materials Chemistry C 4(48):11499-11507
Publisher Policy:Reproduced under a Creative Commons License

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