Demonstration of thermal modulation using nanoscale and microscale structures for ultralarge pixel array photothermal transducers

Large-pixel-array infrared emitters are attractive in the applications of infrared imaging and detection. However, the array scale has been restricted in traditional technologies. Here, we demonstrated a light-driven photothermal transduction approach for an ultralarge pixel array infrared emitter. A metal-black coating with nanoporous structures and a silicon (Si) layer with microgap structures were proposed to manage the thermal input and output issues. The effects of the nanoscale structures in the black coating and microscale structures in the Si layer were investigated. Remarkable thermal modulation could be obtained by adjusting the nanoscale and microscale structures. The measured stationary and transient results of the fabricated photothermal transducers agreed well with the simulated results. From the input view, due to its wide spectrum and high absorption, the black coating with nanoscale structures contributed to a 5.6-fold increase in the temperature difference compared to that without the black coating. From the output view, the microgap structures in the Si layer eliminated the in-plane thermal crosstalk. The temperature difference was increased by 340% by modulating the out-of-plane microstructures. The proposed photothermal transducer had a rising time of 0.95 ms and a falling time of 0.53 ms, ensuring a fast time response. This method is compatible with low-cost and mass manufacturing and has promising potential to achieve ultralarge-array pixels beyond ten million.

A Review - Black Oxide Coating on Metal Substrates of Steels, Aluminium, Magnesium and Copper

Aluminium, magnesium, copper, steels and their alloys are generally used in vast applications like automobile, ship, architecture, aerospace due their properties of high strength to weight ratio, good toughness, ease of recycling and good thermal conductivity. In practical applications, surface treatment is required to meet design requirements and also improves the long-term corrosion resistance and functionality. To enhance surface properties electro deposition, sol-gel, anodization and gas phase deposition are causally used in many industries. For achieving better results, one of the alternative coating has been developed such as black coating to modify the metal substrate properties. These black coating can be prepared by conventional method as well as other methods like micro arc oxidation, plasma electrolytic oxidation and pulse micro arc oxidation techniques. Conventional coloring method shows some disadvantages, for instance, poisonous Cr6+ ions are formed while preparing black oxide coating by conversion of chromium. To avoid such disadvantages, micro arc oxidation, plasma electrolytic oxidation and pulse micro arc oxidation are developed. Based on these techniques, surface properties like long-term corrosion resistance, wear resistance, biocompatibility and decoration are enhanced. Black coatings have high hardness, good bonding with metal substrate, light aging resistance and higher thickness of coating due to strongest absorption ability. This paper mainly focusses the generation of black oxide coating on steel, aluminum, magnesium and copper.

Development of an electrochemical sensor based on carbon black for the detection of cannabidiol in vegetable extracts

A glassy carbon electrode chemically modified with a carbon black coating is proposed here for the rapid and portable determination of cannabidiol (CBD) in a commercial Cannabis seed oil and in fibre-type Cannabis sativa L. leaves.

Effect of Different Color Paste on Properties of Fluorine Resin/Aluminum Infrared Low Emissivity Coating

The effect of the four kinds of red, dark yellow, purple, and black pastes on the properties of fluorine resin/aluminum low emissivity coating was studied. The infrared emissivity coatings with red and black pastes were higher than the coatings with dark yellow and purple pastes. The hardness of the coatings with red, dark yellow, and purple color pastes was 6H, and that with black pastes was 6B. The adhesion and impact resistance of dark yellow coating was better, followed by red and purple, and the adhesion and impact resistance of black coating was the worst. Electrochemical polarization curves indicated that fluorine resin coatings with purple paste had better corrosion resistance. After the salt water resistance test, there was no obvious loss of light in the coatings with the four kinds of color pastes. The purple paste coating had no obvious loss of light and less bubble, suggesting that the fluorine resin/aluminum low emissivity coating with purple paste had better performance. The results of this study provide a new prospect for the application of infrared low emissivity coating in infrared stealth and compatibility with visible light.

Experimental study on the structure and properties of modified nonwoven filter fibers by impregnation with carbon black

With the increasingly serious air pollution, it is urgent to build a good indoor environment. How to improve performance of filter fiber materials has become the mainstream approach. In this article, the structure and filtration performances of nonwoven filter fibers before and after impregnation with carbon black were tested and analyzed. The results showed that a carbon black coating layer was wrapped on the surfaces of the changed nonwoven fabric filter fibers. The porosity of fibers decreased from 97.81% to 95.35%. The filtration efficiency of PM1.0, PM2.5, and PM10 increased by 16.8%, 28.0%, and 11.7%, respectively, at the best filtration velocity of 0.8 m/s. The filtration efficiency of PM2.5 had the most significant improvement. But the resistance increased by 1.18 times at the same time. The matching between filtration efficiency and resistance should be considered in using. This study provides reference value for the synthesis and application of new filter materials.