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Polymer based organic photovoltaic systems, which can be mass-produced by roll-to-roll printing technology, hold the promise for a cost-effective, lightweight and mechanical flexible solar energy conversion platform. Nevertheless, challenges still remain for large-scale applications of these flexible solar cells. One of the issues of great importance is the long-time reliability of solar cell module...
In this paper, simulation and optimization of a micro flow sensor is presented. Modeling of the micro flow sensor using ANSYS Fluent for temperature distribution is studied. The detailed structure of the micro flow sensor chip is considered in the simulation model. What's more, the temperature dependencies of physical properties of air are defined to improve the model precision. As a key parameter,...
Polymer based organic photovoltaic systems, which can be mass-produced by roll-to-roll printing technology, hold the promise for a cost-effective, lightweight and mechanical flexible solar energy conversion platform. Nevertheless, challenges still remain for large-scale applications of these flexible solar cells. One of the issues of great importance is the long-time reliability of solar cell module...
InGaN quantum dots at high densities (∼1011 dots/cm2) are demonstrated using metalorganic chemical vapor deposition combined with post growth processing of InGaN materials. Optical and structural studies are performed to characterize InGaN quantum dots.
Reliability problems heavily hinder light-emitting diode (LED), especially high brightness LED, from developing rapidly and putting into mass production. One of the most important reasons is that it has so many interfaces which are always the weakest places. LED chip's working temperature is about 90°C and the high mismatch of coefficient of expansion of different materials can inevitably cause failures,...
Impact behaviors of high-power LED are essential due to the possible poor adhesion of interfaces and should be studied. In this study, the analysis of dynamic response for high-power LED module under impact load is conducted with simplified theoretical analysis, experimental testing and numerical simulation. A self-made microelectronics drop impact tester is established. Then reliability performances...
We have demonstrated a multi-color array of photonic crystal lasers on a single chip. By lithographically defining the geometrical properties of the photonic crystals we have achieved tuning from 376–435 nm using a single epitaxial growth.
The phenomenon that phosphor particles tend to settle in silicone is widely known. Recent researchers have discussed the effects of phosphor concentration on luminous efficacy of LED packaging. But to produce reliable products, mechanical and interfacial considerations are also essential. In this paper, the mechanical behaviors and interfacial strength of silicone with different levels of phosphor...
Among several materials used in LED packaging, phosphor-filled silicone plays an important role on optical performance and long-time reliability of the module. Many researchers have studied optical properties of phosphor, but few have considered mechanical behavior of phosphor-filled silicone. In this paper, mechanical properties of YAG phosphor-filled silicone are obtained. Tensile tests, which are...
As the market is desperate for better performed, miniaturized, highreliableand lower-priced electronic devices, nowadays, three dimensional integrated circuit (3D IC) seems to be a promising technology which can meet these requirements. However, many issues hinder this technology from being developedrapidly, among which the reliability of through silicon via(TSV) is one of the major concerns. Because...
The effect of nickel coating upon the torsional behaviors of single-walled carbon nanotube (SWCNT) was defined, and torsion behaviors were investigated using the molecular dynamics (MD) simulation method. In this work, an armchair (6,6) carbon nanotube was considered. Both SWCNT and SCNT coating Ni (SWCNT-Ni) were analyzed at 0K and 300K. By simulating torsion process of SWCNT-Ni, mechanical behaviors...
When one-dimensional single atom chain was placed at the center of single wall carbon nano-tube (SWCNT) along the axis, and using the molecular dynamics simulation, the mechanical strength of a single-walled could be obtained in terms of the stress-strain curve. At this temperature of 0K, the ultimate stress of a SWCNT with one-dimensional single atom chain was higher than that of a SWCNT without...
High junction temperature accelerates the degradation of the chips and the package materials of high power light emitting diodes (LEDs). In this paper, two experiments were conducted to investigate the fluctuation of junction temperature in the aging process. At the ambient temperature of 65°C, the samples from four different types of LED packages were used to investigate the variation of junction...
High power light-emitting diodes (LED) are widely applied in many fields for their special advantages compared with other light sources. Many researches on LED reliability have been conducted in order to build the better LED design. However, seldom detailed reasons for the LED performance degradation are illustrated in the previous research when LED modules work under a certain thermal and moisture...
The attachment of the silicon piezoresistive pressure sensor die to the substrate is one of the most critical steps in the production of highly accurate pressure sensor. In this paper, single parameter of the adhesive affecting the silicon piezoresistive pressure sensor's output characteristics has been studied. Shear strength of the adhesive with optimized parameters also has been evaluated. Material...
To analyze the effect of moisture on the reliability of LED modules, diffusivity of packaging materials must be provided. Polycarbonate (PC) is an important material for LED lens. Its diffusivity measurement is usually based on the solution of one-dimensional diffusion. In this paper, the diffusivity measurement of PC was conducted. Simulation and analytical close-form solution (CFS) were also used...
There are many vibration energy in nature, vibration energy harvesting is an attractive technique for low-power devices. In this paper, a new vibration energy harvesting by carbon nanotube network(NTN)/polydimethylsiloxane(PDMS) composite was investigated. The composite of NTN embedded in PDMS matrix has been fabricated by using filtration, standard integrated circuits processes and transfer process...
With international practice and needs of business own development, it's has become more and more common to carry out EPC project in enterprises' contract. Comparing with the traditional patterns of contract, the owners will not involve in the specific process of project in EPC model, so the decision risk of the owners is increased. Through analyzing of EPC contract model, to the ambiguity and uncertainty...
As thermal performance is importance for high-power LED devices, there exists a need to build a validated model to clarify the thermal transfer mechanisms in the LED chip in terms of the chip materials and structures. High-power LED was numerically investigated using the finite element method. A series of substrate materials with different thermal conductivity and thicknesses were studied. The impact...
Aiming to study dynamic mechanical properties of the transparent silicone resins for LEDs packaging and the effects of dynamic mechanical properties on the reliability of high power LEDs, dynamic mechanical analysis (DMA) has been adopted to study one silicone resin used for packaging high power white light LEDs. The viscoelastic behavior of silicone resin was obtained from multi-frequencies dynamic...
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