Preparation and properties of vinylphenyl-silicone resins and their application in LED packaging

Chen, Jianjun; Fu, Zien; Huang, Hengchao; Zeng, Xingrong; Chen, Zhonghua

doi:10.1039/c6ra08295e

Cited by 19 publications

(16 citation statements)

References 31 publications

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“…Based on the gradual substitution of MeSi(OMe) 3 by Me 2 Si(OMe) 2 the overall concentration of phenyl groups, which also inuences the refractive index. 16 The refractive index of sample 1 and 2 could not be determined by Abbé refractometry due to its very high viscosity at 20 C. By extrapolation we expect the RI of these materials to be in the range of 1.508-1.510.…”

Section: Refractive Index Of Unconsolidated Gelsmentioning

confidence: 96%

“…Due to the stepwise substitution of TAS by DAS units from sample 1 to 8 a simultaneous decrease of cross-linking respectively of viscosity is expected. 16 The viscosity of sample 1 and 2 was too high for a determination at room temperature. An increase in temperature to 110 C results in a signicant decrease of the absolute value of viscosity of the samples from 1 to 8 (Fig.…”

Section: Viscosity Of Unconsolidated Gelsmentioning

confidence: 98%

“…As expected, a decrease of TAS/DAS ratio leads to a decrease of viscosity from 362 079 to 1324 mPa s. This trend was also reported in literature for vinylphenylpolysiloxane (22 658 to 3928 mPa s). 16 Comparable non vinyl containing but also curable sol-gel based materials are solid and cannot be processed at room temperature but also soen at higher temperatures. 26,[34][35][36][37][38] Generally viscosities of 10 000-300 000 mPa s respectively 3000-15 000 mPa s are required for the manufacturing of optoelectronic devices by moulding or dispensing processes.…”

Section: Viscosity Of Unconsolidated Gelsmentioning

confidence: 99%

“…[10][11][12] The two most common used packaging materials for optoelectronic applications are twocomponent polysiloxane elastomers, thermally curable by platinum catalysed hydrosilylation (Scheme 1), or irradiation curable epoxy systems. 7,[13][14][15][16][17] The commercially used two-component polysiloxanes are suitable for many different applications and meet all the important requirements for conventional LEDs with inorganic converters. However, new applications like rare earth reduced LEDs containing converters based on organic dyes have additional requirements.…”

Section: Introductionmentioning

confidence: 99%

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Platinum free thermally curable siloxanes for optoelectronic application – synthesis and properties

2019

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Polysiloxanes for applications in the area of optical devices are usually based on two-component platinum catalysed cross-linked materials. Here we report the synthesis and properties of a novel one-component siloxane that can be thermally cured showing similar tailorable properties like commercially available encapsulation systems without using a noble metal catalyst. The pre-curing material is formed by an acid catalysed condensation reaction of trialkoxysilanes (TAS), dialkoxysilanes (DAS) and alkoxy-terminated polysiloxanes. NMR analysis of the formed polymeric compounds reveal that the materials are partially cross-linked gels. The obtained compounds can be thermally cured and consolidated at temperatures between 160 and 200 C. Depending on the composition a tuneable hardness in between 50-90 Shore A, refractive indices of 1.494-1.505, as well as high temperature stabilities up to 443 C were obtained.The high thermal-and photostability, the high transparency, as well as the tailorable refractive index makes these materials to ideal systems for optoelectronic applications. Investigations under increased temperatures and high-density illumination reveal that the material can withstand conditions, which are typical for high-performance light emitting diodes (LED).

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Section: Refractive Index Of Unconsolidated Gelsmentioning

confidence: 96%

Section: Viscosity Of Unconsolidated Gelsmentioning

confidence: 98%

Section: Viscosity Of Unconsolidated Gelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Platinum free thermally curable siloxanes for optoelectronic application – synthesis and properties

2019

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“… On one hand, the RI of conventional silicone encapsulant is about 1.41, which is relatively lower than that of LED chip. The RI gap between the chip and the encapsulant brings in significant internal reflection, resulting in reduced light extraction efficiency of conventional LED packages . On the other hand, the high gas permeability of conventional silicone without barrier filler would reduce the service life of LED device, especially in outdoor environment.…”

Section: Introductionmentioning

confidence: 99%

A facile route to prepare homogeneous silicone resin doped with titanium

Chen

Huang

et al. 2019

J of Applied Polymer Sci

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A facile route was introduced to prepare homogeneous silicone resin doped with titanium hybrid with high refractive index (RI). Specifically, the hybrids were obtained from the transesterification of hydroxyl‐phenyl‐vinyl silicone resin and titanium isopropoxide under anhydrous conditions. The structures of hybrid silicone and their corresponding intermediates (hydroxyl‐phenyl‐vinyl silicone) were characterized by nuclear magnetic resonance spectroscopy (1H NMR, 29Si NMR) as well as Fourier transform infrared spectroscopy (FTIR). The hybrids had a transmittance of more than 88% ranging from 450 nm to 800 nm, a high RI of 1.585, and a lower water vapor permeability of 3.58 g /m2.24h. Results from FTIR showed intensity of Ti‐O‐Si bond in hybrid decrease with extended the storage time, but the properties of cured hybrids including optical, mechanical, and gas permeability were not influenced. Compared to chips encapsulated with pure silicone, the luminous efficiency of the chips encapsulated with hybrids was improved from 138.6 lm/W to 156.4 lm/W. The thermal shock and hygrothermal aging test also demonstrated the hybrids had a wide range application in light‐emitting diode (LED) packaging. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47834.

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Oligo‐Condensation Reactions of Silanediols with Conservation of Solid‐State‐Structural Features.

Kannengießer,

Morgenstern,

Janka

et al. 2024

Chemistry A European J

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Oligo‐ and polysiloxanes are usually prepared by condensation reactions in solvents without control of stereochemistry. Here we present a solventless thermal condensation of stable organosilanols which act as precursors in a thermal condensation reaction. We investigated the condensation reactions of organosilanediols with different organic substituents, having in common at least one aromatic group. The condensation kinetics of the precursors observed by NMR spectroscopy revealed a strong dependence on temperature, time, and substitution pattern at the silicon atom. SEC measurements showed that chain length increases with increasing condensation temperature and time and lower steric demand of the substituents, which also influences the glass transition temperatures (Tg). X‐ray diffraction studies of the crystalline silanediols and their condensation products revealed a structural correlation between the substituent location in the crystalline precursors and the formed polysiloxanes induced by the hydrogen bond pattern. In certain cases, it is possible to carry out topotactic polymerization in the solid‐state, which has its origin in the crystal structure.

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Preparation and properties of vinylphenyl-silicone resins and their application in LED packaging

Abstract: The results of spectrophotometry and TEM revealed that materials with a higher homogeneity degree of morphological structure could obtain 98.7% of transmittance at a wavelength of 680 nm.

Cited by 19 publications

References 31 publications

Platinum free thermally curable siloxanes for optoelectronic application – synthesis and properties

Platinum free thermally curable siloxanes for optoelectronic application – synthesis and properties

A facile route to prepare homogeneous silicone resin doped with titanium

Oligo‐Condensation Reactions of Silanediols with Conservation of Solid‐State‐Structural Features.

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