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Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Thermoelectric properties of Cu-dispersed bi0.5sb1.5te3 | Kim et al. Nanoscale Research Letters 2012 7 2 http www.nanoscalereslett.eom content 7 1 2 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Thermoelectric properties of Cu-dispersed bi0.5sb1.5te3 Il-Ho Kim1 Soon-Mok Choi2 Won-Seon Seo2 and Dong-Ik Cheong3 Abstract A novel and simple approach was used to disperse Cu nanoparticles uniformly in the Bi0.5Sb1.5Te3 matrix and the thermoelectric properties were evaluated for the Cu-dispersed Bi0.5Sb1.5Te3. Polycrystalline Bi0.5Sb1.5Te3 powder prepared by encapsulated melting and grinding was dry-mixed with Cu OAc 2 powder. After Cu OAc 2 decomposition the Cu-dispersed Bi0.5Sb1.5Te3 was hot-pressed. Cu nanoparticles were well-dispersed in the Bi0.5Sb1.5Te3 matrix and acted as effective phonon scattering centers. The electrical conductivity increased systematically with increasing level of Cu nanoparticle dispersion. All specimens had a positive Seebeck coefficient which confirmed that the electrical charge was transported mainly by holes. The thermoelectric figure of merit was enhanced remarkably over a wide temperature range of 323-523 K. PACS 72.15Jf 72.20.Pa Keywords chalcogenides electronic materials composites electrical properties thermal conductivity Introduction Thermoelectric materials require a high Seebeck coefficient a high electrical conductivity s and low thermal conductivity k at an application temperature T in kelvin for a high figure of merit ZT a2ơTk-1 which is related to the thermoelectric energy conversion efficiency. On the other hand these parameters are not independent for a given material. The quantity a2Ơ is called the power factor and the Seebeck coefficient and electrical conductivity are related to the carrier concentration and mobility effective mass of carriers . The thermal conductivity has contributions from lattice vibrations related to phonon scattering and charge carrier transportations affected by the carrier concentration. The phonon glass and electron .
