| 초록 |
Energy from fossil fuels causes air pollution, climate change, and global warming due to the release of harmful substances during combustion, so it must be replaced with renewable energy as a result. In line with this trend, the technology that utilizes waste heat as a thermoelectric (TE) material is attracting a lot of attention as an eco-friendly mechanism with high efficiency, wide applicable temperature range, and high reliability without moving parts. Among various thermoelectric materials, Cu2-xSe, a copper-based chalcogenide with high TE efficiency, has been actively studied for medium temperature range due to its low toxicity, cost-effectiveness, and liquid-like heat transfer mechanism that results in a low heat capacity with increasing temperature. In order to maximize the TE characteristics, a technique for reducing thermal conductivity by increasing phonon scattering to nano-sized grains through a powder metallurgy process is attracting attention. Although various synthetic methods cause low yield and difficulties in process optimization and commercialization. According to homogeneous nucleation and growth theory, the critical nuclei radius and critical energy to generate specific nuclei depend on a precursor concentration in the reaction medium. In general, the nucleation rate is faster at high precursor concentrations, which means that smaller nanoparticles can be synthesized in large quantities. However, the actual synthesis process using high concentration precursors causes problems in which particles are uneven in size and increase in size. Therefore, a new methodology is needed to solve this problem. In this study, solution-based mass production of Cu2-xSe nanoparticles was attempted using a high concentration metal complex precursor and ultrasound energy. This approach can prevent particle agglomeration by introduced complex molecules and instantaneous uniform energy supply and recovery via ultrasound. Using this facile and cost-effective strategy, Cu2-xSe nanoparticles with an average diameter of 150nm were successfully synthesized at room temperature and atmospheric pressure. |
