Red-Emitting Coatings forMultifunctional UV/Red Emitting LEDs Applied in Plant Circadian Rhythm Control
authors Bispo, AG; Lima, SAM; Carlos, LD; Ferreira, RAS; Pires, AM
nationality International
journal ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
keywords PHOTOLUMINESCENCE PROPERTIES; LUMINESCENT PROPERTIES; LOCAL-STRUCTURE; LIGHT; PHOSPHORS; DIODES; EU3+; FABRICATION; EMISSION; EFFICACY
abstract Multifunctional light-emitting diodes (LEDs) formed by coating deep-UV-emitting (<300 nm) LED chips with downshifting phosphors are of great interest for applications in indoor farms as both antibacterial (UV radiation) and photosynthetic agent (red light). Challenges include the fabrication of high-brightness downshifting converter films with controlled thickness excited in the deep-UV spectral region. We address it by optimizing the amount of Ba2SiO4: Eu(III) red-emitting phosphor dispersed in poly (methyl) methacrylate (PMMA), yielding luminescent films with tunable thickness. Taking advantage of the intra-4f(6) transitions, the Eu(III) luminescence is used as local probe, pointing out the presence of 8 non-equivalent local sites for the lanthanides. PMMA enables the processing of flexible films and simultaneously acts as a selective filter to deep-UV radiation, controlling the amount of UV radiation for indoor farm applications. Moreover, after the dispersion in PMMA, the Eu(III)-based luminescence remains analogous to that of the isolated phosphor with an absolute emission quantum yield of 0.11 +/- 0.01, confirming that Ba2SiO4:Eu(III)/PMMA films display desirable features to be used as coatings of deep-UV emitting LEDs toward multifunctional devices for indoor farm application. (C) The Author(s) 2019. Published by ECS.
publisher ELECTROCHEMICAL SOC INC
issn 2162-8769
year published 2019
volume 9
issue 1
digital object identifier (doi) 10.1149/2.0122001JSS
web of science category Materials Science, Multidisciplinary; Physics, Applied
subject category Materials Science; Physics
unique article identifier WOS:000487226800003
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journal analysis (jcr 2017):
journal impact factor 1.808
5 year journal impact factor 1.830
category normalized journal impact factor percentile 48.910
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