Thermal Conductivity and Mechanical Properties of Low-Density Silicone Rubber Filled With Al2O3 and Graphene Nanoplatelets

2017 ◽  
Vol 10 (1) ◽  
Author(s):  
Yingchun Zhang ◽  
Wei Yu ◽  
Liye Zhang ◽  
Junshan Yin ◽  
Jingkang Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Silicone Rubber ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Thermal Contact ◽  
Graphene Nanoplatelets ◽  
Rubber Matrix ◽  
Heat Conducting ◽  
Light Emitting ◽  
Potential Applications

A simple approach is developed to obtain a multiscale network of heat conducting by filling spherical alumina (S-Al2O3) and graphene nanoplatelets (GnPs) into silicone rubber (SR). This unique structure effectively minimizes the thermal contact resistance between fillers and matrix. The physical properties of the composites are characterized by thermal conductivity, density, and tensile strength. A high thermal conductivity of 3.37 Wm−1 K−1 has been achieved, which is 47.1% higher than the single filler at the same loading. A strong and obvious synergistic effect has been observed as S-Al2O3 and GnPs filled into silicone rubber matrix. It is interesting that the composites with GnPs have the lower density (2.62 g/cm3, reduced by 6%) and the superior tensile performance, compared to silicone rubber composite with neat S-Al2O3. The composites have the potential applications in heat dissipation of light-emitting diode.

Heat Dissipation Simulation Research of LED Downlight and Optimization of Light Source Layout

2013 ◽  
Vol 760-762 ◽  
pp. 443-450
Author(s):  
Jie Chen ◽  
Zhong Chen ◽  
Jie Chen ◽  
Xiao Hong Li ◽  
Ya Feng Shen ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Light Source ◽  
Heat Load ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Measurement Methods ◽  
Simulation Software ◽  
Simulation Research ◽  
Light Emitting ◽  
Dissipation Model

In order to solve the heat dissipation problem of LED (light-emitting diode) downlight, CFD thermal simulation software was used to establish LED downlight dissipation model. Materials thermal conductivity, thermal resistance, thermal emissive values, heat load forms and other factors were all taken in considered, and then numerical simulation combined with laboratory measurement methods was used to analysis the lamps dissipation. Based on this method, focused on the dissipation effect with different LED quantities and LED ring distances, and then optimized light source layout of current LED downlight products. After experimental verification, LED working temperatures were more ideal after the light source layout optimized, and it can improve the LED lamp lifetime effectively, this result also has important practice significance in the future LED downlight design process.

Reliability of High-Power Light Emitting Diode Attached With Different Thermal Interface Materials

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Xin Li ◽  
Xu Chen ◽  
Guo-Quan Lu
Keyword(s):  
High Power ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Temperature Cycling ◽  
Fluorescent Light ◽  
Light Sources ◽  
Light Emitting ◽  
Die Attach ◽  
Nanosilver Paste ◽  
Interconnection Material

As a solid electroluminescent source, white light emitting diode (LED) has entered a practical stage and become an alternative to replace incandescent and fluorescent light sources. However, due to the increasing integration and miniaturization of LED chips, heat flux inside the chip is also increasing, which puts the packaging into the position to meet higher requirements of heat dissipation. In this study, a new interconnection material—nanosilver paste is used for the LED chip packaging to pursue a better optical performance, since high thermal conductivity of this material can help improve the efficiency of heat dissipation for the LED chip. The bonding ability of this new die-attach material is evaluated by their bonding strength. Moreover, high-power LED modules connected with nanosilver paste, Sn3Ag0.5Cu solder, and silver epoxy are aged under hygrothermal aging and temperature cycling tests. The performances of these LED modules are tested at different aging time. The results show that LED modules sintered with nanosilver paste have the best performance and stability.

Thermal conduction characteristics of silicone composites including ultrasonic-treated graphite

2021 ◽  
pp. 002199832110595
Author(s):  
Weontae Oh ◽  
Jong-Seong Bae ◽  
Hyoung-Seok Moon
Keyword(s):  
Thermal Conductivity ◽  
Ultrasonic Treatment ◽  
Thermal Conduction ◽  
Light Emitting Diode ◽  
Thermal Interface Material ◽  
Ultrasonic Power ◽  
Lighting System ◽  
Thermal Interface ◽  
Light Emitting ◽  
Inorganic Oxides

The microstructural change of graphite was studied after ultrasonic treatment of the graphite. When the graphite solution was treated with varying ultrasonic power and time, the microstructure changed gradually, and accordingly, the thermal conductivity characteristics of the composite containing the as-treated graphite was also different with each other. Thermal conductivity showed the best result in the silicone composite containing graphite prepared under the optimum condition of ultrasonic treatment, and the thermal conductivity of the composite improved proportionally along with the particle size of graphite. When the silicone composite was prepared by using a mixture of inorganic oxides and graphite rather than graphite alone, the thermal conductivity of the silicone composite was further increased. A silicone composite containing graphite was used for LED (light emitting diode) lighting system as a thermal interface material (TIM), and the temperature elevation due to heat generated, while the lighting was actually operated, was analyzed.

scholarly journals 2,7(3,6)-Diaryl(arylamino)-substituted Carbazoles as Components of OLEDs: A Review of the Last Decade

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6754
Author(s):  
Gintare Krucaite ◽  
Saulius Grigalevicius
Keyword(s):  
Light Emitting Diode ◽  
Delayed Fluorescence ◽  
Inorganic Materials ◽  
Carrier Injection ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Host Materials ◽  
Useful Components ◽  
Potential Applications ◽  
Forming Characteristics

Organic light emitting diode (OLED) is a new, promising technology in the field of lighting and display applications due to the advantages offered by its organic electroactive derivatives over inorganic materials. OLEDs have prompted a great deal of investigations within academia as well as in industry because of their potential applications. The electroactive layers of OLEDs can be fabricated from low molecular weight derivatives by vapor deposition or from polymers by spin coating from their solution. Among the low-molar-mass compounds under investigation in this field, carbazole-based materials have been studied at length for their useful chemical and electronic characteristics. The carbazole is an electron-rich heterocyclic compound, whose structure can be easily modified by rather simple reactions in order to obtain 2,7(3,6)-diaryl(arylamino)-substituted carbazoles. The substituted derivatives are widely used for the formation of OLEDs due to their good charge carrier injection and transfer characteristics, electroluminescence, thermally activated delayed fluorescence, improved thermal and morphological stability as well as their thin film forming characteristics. On the other hand, relatively high triplet energies of some substituted carbazole-based compounds make them useful components as host materials even for wide bandgap triplet emitters. The present review focuses on 2,7(3,6)-diaryl(arylamino)-substituted carbazoles, which were described in the last decade and were applied as charge-transporting layers, fluorescent and phosphorescent emitters as well as host materials for OLED devices.

Thermal Analysis of High Power Light Emitting Diodes Package

2011 ◽  
Vol 687 ◽  
pp. 215-221
Author(s):  
Yuan Yuan Han ◽  
Hong Guo ◽  
Xi Min Zhang ◽  
Fa Zhang Yin ◽  
Ke Chu ◽  
...  
Keyword(s):  
Finite Element Method ◽  
High Power ◽  
Thermal Field ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Convective Heat Exchange ◽  
Input Power ◽  
Junction Temperature ◽  
Original Structure ◽  
Light Emitting

With increasing of the input power of the chips in light emitting diode (LED)， the thermal accumulation of LEDs package increases. Therefore solving the heat issue has become a precondition of high power LED application. In this paper, finite element method was used to analyze the thermal field of high power LEDs. The effect of the heatsink structure on the junction temperature was also investigated. The results show that the temperature of the chip is 95.8°C which is the highest, and it meets the requirement. The conductivity of each component affects the thermal resistance. Convective heat exchange is connected with the heat dissipation area. In the original structure of LEDs package the heat convected through the substrate is the highest, accounting for 92.58%. Three heatsinks with fin structure are designed to decrease the junction temperature of the LEDs package.

Enhanced Thermal Conductivity for Graphene Nanoplatelets/Epoxy Resin Composites

2017 ◽  
Vol 10 (1) ◽  
Author(s):  
Dahai Zhu ◽  
Yu Qi ◽  
Wei Yu ◽  
Lifei Chen ◽  
Mingzhu Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Epoxy Resin ◽  
Mass Fraction ◽  
Great Influence ◽  
Graphene Nanoplatelets ◽  
Resin Matrix ◽  
Heat Conducting ◽  
Factors Affecting ◽  
Molding Method ◽  
Ep Matrix

Graphene nanoplatelets (GNPs) have excellent thermal conductivity. It can significantly improve the heat-conducting property of epoxy resin (EP) matrix. In this paper, the GNPs/EP composites were successfully prepared by using ultrasonication and the cast molding method. The prepared GNPs/EP composites were systematically characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermal conductivity analyzer. Some factors affecting the thermal transfer performance of the composites were discussed. The defoamation has great influence on the thermal conductivity of composite. There is a nearly linear relationship between the mass fraction and the thermal conductivity of composite when the mass fraction of GNPs is below 4.3%. The results show that when the mass fraction of GNPs is 4.3% with crushing time of 2 s, the thermal conductivity of GNPs/EP composite is up to 0.99 W/m K. The thermal conductivity is increased by 9.0% compared with that without pulverization treatment (0.91 W/m K). When it is ground three times, the thermal conductivity of composite reaches the maximum (1.06 W/m K) and it is increased by 307.7% compared with that of epoxy resin matrix.

Improved Heat Dissipation in GaN-Based Thin-Film Light-Emitting Diode with Lateral-Electrode Configuration

2015 ◽  
Vol 7 (2) ◽  
pp. 283-286
Author(s):  
Jiang-Yong Zhang ◽  
Lei-Ying Ying ◽  
Ming Chen ◽  
Wen-Jie Liu ◽  
Jian Yu ◽  
...  
Keyword(s):  
Thin Film ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Electrode Configuration ◽  
Light Emitting
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