Recently, the application of phosphorene structure analogues in gas sensors has been a hot research topic since the appearance of phosphorene. SnSe monolayer as one of them has been proved to be much more stable properties than phosphorene. Based on the density-functional theory, the interaction between gas molecules (CO, CO ₂ , O ₂ , NO, NH ₃ , SO ₂ and NO ₂ ) and SnSe monolayer are theoretically investigated by first-principles calculation. Macroscopically, gas molecules selective adsorption of SnSe monolayer is analyzed by molecular dynamics. Compared to CO, CO ₂ , O ₂ , SnSe monolayer performs stronger affinity for SO ₂ and NO ₂ , which possesses appropriate adsorption energies (−6.000 eV and −0.759 eV) and elevated charge transfers (−0.239 e and −0.328 e). SnSe monolayer chemical adsorption of NO ₂ , while physically adsorbing SO ₂ , is more suitable for the adsorption mode of SO ₂ sensors. Surprisingly, the adsorption amount of SO ₂ is 6 times that of NO ₂ . Therefore, the adsorption of SO ₂ is more likely to occur compared to other gas molecules. For a mixed environment of SO ₂ and NO ₂ , the adsorption quantity of SO ₂ is not significantly affected, while the adsorption of NO ₂ is inhibited. Therefore, the SnSe monolayer could be a promising candidate as SO ₂ sensors with high selectivity and sensitivity.

IGBT device is developed from silicon to wide bandgap semiconductor materials, and its working temperature has reached to 300 °C, so the encapsulation is particularly important. NanoCu paste is investigated under H2 at 300°C. A chip is linked to DBC substrate by nanoCu paste under air with different temperature. Results shows the increase of sintered time temperature effectively reduce the porosity of sintered layer and enhance the strength.

The color coordinate shift of light-emitting diode (LED) lamps is investigated by running three stress-loaded testing methods, namely step-up stress accelerated degradation testing, step-down stress accelerated degradation testing, and constant stress accelerated degradation testing. A power model is proposed as the statistical model of the color shift (CS) process of LED products. Consequently, a CS mechanism constant is obtained for detecting the consistency of CS mechanisms among various stress-loaded conditions. A statistical procedure with the proposed power model is then derived for the CS paths of LED lamps in step-loaded stress testing. Two types of commercial LED lamps with different capabilities of heat dissipation (CHDs) are investigated. Results show that the color coordinates of lamps are easily modified in various stress-loaded conditions, and different CHDs of lamps may play a crucial role in the various CS processes. Furthermore, the proposed statistic power model is adequate for the CS process of LED lamps. The consistency of CS mechanisms in step-loaded stress testing can also be detected effectively by applying the proposed statistic procedure with the power model. Moreover, the constant assumption in the model is useful for judging the consistency of CS mechanisms under various stress-loaded conditions.

Although color shift is one of the key issues to be considered for the failure of LEDs products, there is limited literature that correlated LED products' lifetime performance to their color shift over time. This is mainly due to the lack of a suitable model to define the color shift over time. In this paper, a methodology for characterizing and predicting the color shift of the polycarbonate materials in LED products is developed. It had shown that the color shift follows the 1st order reaction. Furthermore, the rate coefficient k of the reaction was found to follow Arrhenius relationship with activation energy of 0.046eV.