tailieunhanh - Báo cáo hóa học: " Electrospun ZnO Nanowires as Gas Sensors for Ethanol Detection"

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: Electrospun ZnO Nanowires as Gas Sensors for Ethanol Detection | Nanoscale Res Lett 2009 4 513-517 DOI s11671-009-9271-4 NANO EXPRESS Electrospun ZnO Nanowires as Gas Sensors for Ethanol Detection Wan-Yu Wu Jyh-Ming Ting Po-Jung Huang Received 30 June 2008 Accepted 6 February 2009 Published online 4 March 2009 to the authors 2009 Abstract ZnO nanowires were produced using an electrospinning method and used in gas sensors for the detection of ethanol at 220 C. This electrospinning technique allows the direct placement of ZnO nanowires during their synthesis to bridge the sensor electrodes. An excellent sensitivity of nearly 90 was obtained at a low ethanol concentration of 10 ppm and the rest obtained at higher ethanol concentrations up to 600 ppm all equal to or greater than 90 . Keywords Zinc oxide Electrospinning Ethanol sensor Sensitivity ZnO is an interesting chemically and thermally stable n-type semiconductor with a large exciton binding energy 60 meV and a large band gap eV energy. ZnO nanomaterial also appears to be the mostly studied one as it exhibits a wide variety of nanostructures such as nanowires 1 nanowalls 2-4 nanobelts 5 nanorods 6 nanosheets 7 and so on. Among its applications ZnO nanowire is receiving greater interests for use in gas sensors for detecting for example ethanol. ZnO nanowires prepared by a reactive thermal deposition method were used for ethanol sensing 8 . The sensitivity . Ra Rg Ra where Ra and Rg are respectively the resistance of the . Wu . Ting H Department of Materials Science and Engineering National Cheng Kung University Tainan Taiwan e-mail jting@ . Ting . Huang Institute of Nanotechnology and Microsystems Engineering National Cheng Kung University Tainan Taiwan nanowires exposed to air without and with the detecting gas increases from 47 to 98 while the ethanol concentration increases from 1 ppm to 200 ppm at a high temperature of 300 C. However at lower temperatures of 200 C and 250 C the sensitivities drop significantly to 67 and 86 .