High refractive index thermally stable phenoxyphenyl and phenylthiophenyl silicones for light-emitting diode applications

ABSTRACT Creating high refractive index (RI) thermally stable polymers for encapsulating high‐brightness light‐emitting diodes (LEDs) remains a challenge and is an opportunity for improving LED efficiencies. The best previously reported RI for a 200°C heat stable encapsulant for LEDs is 1.56. Here,...

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Bibliographic Details
Published in:Journal of applied polymer science 2014-02, Vol.131 (3), p.np-n/a
Main Authors: Mosley, David W., Khanarian, Garo, Conner, David M., Thorsen, David L., Zhang, Tianlan, Wills, Marty
Format: Article
Language:English
Subjects:
Applied sciences
Chemical modifications
Electronics
Encapsulation
Exact sciences and technology
Inorganic and organomineral polymers
Materials science
optical and photovoltaic applications
optical properties
Optoelectronic devices
packaging
Physicochemistry of polymers
Polymers
properties and characterization
Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
thermosets
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Summary:ABSTRACT Creating high refractive index (RI) thermally stable polymers for encapsulating high‐brightness light‐emitting diodes (LEDs) remains a challenge and is an opportunity for improving LED efficiencies. The best previously reported RI for a 200°C heat stable encapsulant for LEDs is 1.56. Here, we report the use of novel phenoxyphenyl and phenylthiophenyl silicone monomers to give fully formulated encapsulants with RIs above 1.60. These liquid dispensed encapsulants are highly heat stable, showing little change in optical properties after heat aging at 200°C in air for seven weeks, and were also little changed after cycling between −10°C to 85°C over 6 months. Phenoxyphenyl(phenyl) dimethoxysilane and phenylthiophenyl(phenyl) dimethoxysilane monomers were prepared via Grignard reactions. The resulting monomers were copolymerized with commercial silicone monomers and incorporated into hydrosilation‐based thermosets designed for use as LED encapsulants. RIs for the cured polymers were 1.60 at 633 nm (1.62 at 450 nm) for the phenoxyphenyl ether system and 1.62 at 633 nm (1.65 at 450 nm) for the phenylthiophenyl ether system. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39824.
ISSN:0021-8995
1097-4628
DOI:10.1002/app.39824