Thermoelectric generators (TEGs) are a form of energy harvester and eco-friendly power generation system that directly transform thermal energy into electrical energy. The thermoelectric (TE) method of energy harvesting takes advantage of the Seebeck effect, which offers a simple solution for fulfilling the power-supply demand in almost every electronics system. A high-temperature condition is commonly essential in the working mechanism of the TE device, which unfortunately limits the potential implementation of the device. This paper presents an in-depth analysis of TEGs at low operating temperature. The review starts with an extensive description of their fundamental working principles, structure, physical properties, and the figure of merit (ZT). An overview of the associated key challenges in optimising ZT value according to the physical properties is discussed, including the state of the art of the advanced approaches in ZT optimisation. Finally, this manuscript summarises the research status of Bi₂Te₃-based semiconductors and other compound materials as potential materials for TE generators working at low operating temperatures. The improved TE materials suggest that TE power-generation technology is essential for sustainable power generation at near-room temperature to satisfy the requirement for reliable energy supplies in low-power electrical/electronics systems.

This study describes a method by which to synthesize SiO₂-based graphene nanoballs (SGB) using atmospheric pressure chemical vapor deposition (APCVD) with copper vapor assistance. This method should solve the contamination, damage, and high costs associated with silica-based indirect graphene synthesis. The SGB was synthesized using APCVD, which was optimized using the Taguchi method. Multiple synthesis factors were optimized and investigated to find the ideal synthesis condition to grow SGB for thermoelectric (TE) applications. Raman spectra and FESEM-EDX reveal that the graphene formed on the silicon nanoparticles (SNP) is free from copper. The prepared SGB has excellent electrical conductivity (75.0 S/cm), which shows better results than the previous report. Furthermore, the SGB nanofillers in bismuth telluride (Bi₂Te₃) nanocomposites as TE materials exhibit a significant increment in Seebeck coefficients (S) compared to the pure Bi₂Te₃ sample from 109 to 170 μV/K at 400 K, as well as electrical resistivity decrement. This approach would offer a simple strategy to improve the TE performance of commercially available TE materials, which is critical for large-scale industrial applications.

Physics subjects encompass all aspects of nature on both the macroscopic and submicroscopic levels. It was reported that upper secondary school students in Malaysia have difficulties in some topics in Physics which lead to poor performance of students and a lack of interest in the Science, Technology, Engineering and Mathematics subjects. This research assessed the level of students' knowledge of Free Fall Motion, explored the difficulties faced by the students with Free Fall Motion’s topics, measured the effectiveness of the constructivist teaching approach for students in learning Free Fall Motion, and collecting students' perception towards the constructivist teaching approach. This study used a pretest-posttest research design. The population was upper secondary school students from public secondary schools in Malaysia and 30 students were selected as a research sample in this study Using descriptive analysis and paired sample t-tests, it was revealed that majority of students preferred constructivist teaching approach in learning this topic as significant difference in effectiveness of two constructivist coping techniques, visual learning and contextual learning were observed while, assisting students in managing difficulties in learning Free Fall Motion. In conclusion, the constructivist teaching approach improved student`s understanding of the Free Fall Motion concept, however, because of different perspectives and having to adapt to various methods of learning, not all of the students were interested in applying it in their classroom.