Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Direct synthesis of ultrafine tetragonal BaTiO3 nanoparticles at room temperature | Qi et al. Nanoscale Research Letters 2011 6 466 http content 6 1 466 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Direct synthesis of ultrafine tetragonal BaTiO3 nanoparticles at room temperature I- -S Z-S 3 2 2 2 2 3 3 Jian Quan Qi Tao Peng Yong Ming Hu Li Sun Yu Wang Wan Ping Chen Long Tu Li Ce Wen Nan and Helen Lai Wah Chan2 Abstract A large quantity of ultrafine tetragonal barium titanate BaTiO3 nanoparticles is directly synthesized at room temperature. The crystalline form and grain size are checked by both X-ray diffraction and transmission electron microscopy. The results revealed that the perovskite nanoparticles as fine as 7 nm have been synthesized. The phase transition of the as-prepared nanoparticles is investigated by the temperature-dependent Raman spectrum and shows the similar tendency to that of bulk BaTiO3 materials. It is confirmed that the nanoparticles have tetragonal phase at room temperature. Keywords BaTiO3 nanoparticle room temperature Introduction Barium titanate BaTiO3 is widely used for electronic devices in the technological ceramic industry because of its ferroelectric thermoelectric and piezoelectric properties when it assumes the tetragonal structure 1 . As such it can be widely used in capacitors positive temperature coefficient resistors dynamic random access memories electromechanics and nonlinear optics 2 3 . For the existence of the size effect of ferroelectricity and the potential application of bottom-up assembled novel nanostructures the synthesis of ultrafine BaTiO3 nanoparticles is theoretically and technologically important 4 . Many novel synthesis techniques have been developed for this important material. The hydrothermal method is one of the most popular approaches to the perovskite nanostructures directly from solution but the synthesis processes are often conducted at elevated temperatures typically 100 C to 280 C and or under relatively high pressures to .
