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To improve the quality of fused deposition molding (FDM), we introduced ultrasonic vibration into the molding process to enhance the strength of the tensile samples. We used the response surface method to optimize the FDM molding process. We carried out orthogonal experiments to investigate the effects of ultrasonic power and process parameters (extrusion temperature, hotbed temperature, and delamination thickness) on the mechanical properties of fused deposition acrylonitrile butadiene styrene products. We obtained the quadratic regression equations and response surfaces of the data through analysis of variance and significance analysis by software. Last, we received the optimum combination of process parameters for tensile strength as extrusion temperature 233.85 °C, hotbed temperature 93.38 °C, delamination thickness 0.1 mm, and ultrasonic power 43.09 W. [ABSTRACT FROM AUTHOR]

Violet phosphorus quantum dots (VPQDs) have been recently produced to give intense green photoluminescence with excellent stability. Quantum dots are promising temperature sensors. However, the temperature-dependent photoluminescence of VPQDs is still unexplored. Herein, both the steady-state and time-resolved photoluminescence of VPQDs have been investigated at 263–353 K. With increasing temperature, the photoluminescence of VPQDs has been demonstrated to have decreasing intensity, blue shifts, and broaden bandwidth with excellent temperature reversibility. The non-radiative heat escape was found to cause the intensity to decrease. The blue shift was deduced to be due to the interplay between the electron–phonon renormalization and the thermal expansion. The enhanced exciton–phonon coupling was found to be the main cause of broaden bandwidth. The photoluminescence lifetime of VPQDs was measured to be stable at different temperatures. The non-radiation recombination processes have been demonstrated to play a crucial role in the photoluminescence by linking static and dynamic processes to calculate the radiative rate and non-radiative rate variation with temperature. The activation energy of VPQDs was deduced to be 90.25 meV, which is suitable for temperature sensing. The linear correlation of photoluminescence intensity and peak position to temperature gives more accurate dual mode sensing for a wide-range of ratiometric temperature sensors. [ABSTRACT FROM AUTHOR]

IV-VI monochalcogenide SnSe or SnS has recently been proposed as a promising two-dimensional (2D) material for valleytronics and thermoelectrics. We report the synthesis of SnSe nanoflakes and nanostructured thin films with chemical vapor deposition method and their thermoelectric properties. As grown SnSe nanostructures are found to be intrinsically p-type and the single SnSe nanoflake field effect transistor was fabricated. By Ag doping, the power factor of SnSe nanostructured thin films can be improved by up to one order of magnitude compared to the “intrinsic” as grown materials. Our work provides an initial step in the pursuit of IV-VI monochalcogenides as novel 2D semiconductors for electronics and thermoelectrics. [ABSTRACT FROM AUTHOR]