As an increasing attention towards sustainable development of energy and environment, the power electronics (PEs) are gaining more and more attraction on various energy systems. The insulated gate bipolar transistor (IGBT), as one of the PEs with numerous advantages and potentials for development of higher voltage and current ratings, has been used in a board range of applications. However, the continuing miniaturization and rapid increasing power ratings of IGBTs have remarkable high heat flux, which requires complex thermal management. In this work, studies of the thermal management on IGBTs are generally reviewed including analyzing, comparing and classifying the results originating from these researches. The thermal models to accurately calculate the dynamic heat dissipation are divided into analytical models, numerical models and thermal network models respectively. The thermal resistances of current IGBT modules are also studied. According to the current products on a number of IGBTs, we observe that the junction-to-case thermal resistance generally decreases inversely in terms of the total thermal power. In addition, the cooling solutions of IGBTs are reviewed and the performance of the various solutions are studied and compared. At last, we have proposed a quick and efficient evaluation judgment for the thermal management of the IGBTs depended on the requirements on the junction-to-case thermal resistance and equivalent heat transfer coefficient of the test samples.

2D and nanostructured metal sulfide materials are promising in the advancement of several gas sensing applications due to the abundant choice of materials with easily tunable electronic, optical, physical, and chemical properties. These applications are particularly attractive for gas sensing in environmental monitoring and breath analysis. This review gives a systematic description of various gas sensors based on 2D and nanostructured metal sulfide materials. Firstly, the crystal structures of metal sulfides are introduced. Secondly, the gas sensing mechanisms of different metal sulfides based on density functional theory analysis are summarised. Various gas-sensing concepts of metal sulfide-based devices, including chemiresistors, functionalized metal sulfides, Schottky junctions, heterojunctions, field-effect transistors, and optical and surface acoustic wave sensors, are compared and presented. It then discusses the extensive applications of metal sulfide-based sensors for different gas molecules, including volatile organic compounds (i.e., acetone, benzene, methane, formaldehyde, ethanol, and liquefied petroleum gas) and inorganic gas (i.e., CO₂, O₂, NH₃, H₂S, SO₂, NO_x, CH₄, H₂, and humidity). Finally, a strengths–weaknesses–opportunities–threats (SWOT) analysis is proposed for future development and commercialization in this field.

The adsorption of gas molecules, such as N₂, O2, CO₂, H2O, CO, NO, NO₂, H2S, NH₃, and SO₂ on monolayer C₃N has been investigated by means of first-principles and non-equilibrium Green's function calculations. We show that monolayer C₃N is preferable for the NO₂ and SO₂ molecules with suitable adsorption strength and apparent charge transfers. Moreover, the I-V characteristics of C₃N show clear variations after the adsorption of NO₂ and SO₂. Such sensitivity and selectivity to NO₂ and SO₂ molecules make C₃N a promising candidate for highly sensitive gas sensor.

Properties of sulfur dioxide (SO ₂ ) and nitrogen dioxide (NO ₂ ) adsorbed on different types of arsenenes (pristine, boron-, and nitrogen-doped arsenene) are studied with the first-principle approach, which is based on the density functional theory. Adsorption energy, adsorption distance, Hirshfeld charge, and I-V characteristic are calculated. The results demonstrate that NO ₂ and SO ₂ exhibit a chemisorption character on boron-doped arsenene (B-arsenene) while a physisorption character on pristine and nitrogen-doped arsenene (P- and N-arsenene) with moderate adsorption energy. Moreover, analysis of density of state shows a positive change of electronic property when the two gas molecules are adsorbed on pristine/doped arsenenes. According to the I-V characteristic curves, N-arsenene can be treated as an excellent sensing material for SO ₂ gas sensor. Meanwhile, P-arsenene has a potential application in the NO ₂ gas sensor.