Obtenção e caracterização elétrica de filmes finos de SnO2:Sb
Conti, Tiago de Góes
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The growing demand for advanced electronic devices based on nanomaterials has motivated efforts to produce nanoscale building blocks with designed functions. Transparent conducting oxide nanocrystals (TCONs) are particularly promising for the development of such devices. TCONs synthesized in an organic medium play an important role as building blocks because nonaqueous processes allow for greater control of the reaction pathways on a molecular level, enabling the synthesis of nanomaterials with high crystallinity and well-defined and uniform particle morphologies. This work describes the synthesis of highly conducting antimony-doped tin oxide (ATO) nanocrystals prepared via a nonaqueous sol-gel route in the size range of 4-7 nm, as well as insights into its electrical properties when processed as pellet and thin films. The antimony composition was varied from 1 to 18 mol% and the lowest resistivity (4.0x10-4 Ωcm) was observed at room temperature in the SnO2:8.8%molSb composition. The samples were evaluated by XRD, HRTEM, EDX, and SEM, resistivity measurements were taken in the four-probe mode in the temperature range of 77-300K and Hall-effect measurements were taken at room temperature. The preparation of crystalline ATO nanoparticles fully redispersible in organic solvents consists in one pot reaction under solvothermal treatment of tin (IV) chloride and antimony (III) chloride in benzyl alcohol at 150°C for 48h. The ATO nanocrystals were collected by centrifugation and washed twice with THF. The pellets were prepared by pressing 200mg of ATO nanoparticles under 4 MPa into a rigid die in a single axial direction through a rigid punch and the thin films produced via dip-coating deposition on quartz substrate. The results show highly crystalline nanoparticles in a monodisperse colloidal system, dependence on the shape of ATO nanoparticles as a function of Sb distribution and low resistivity.