Browsing by Author "Modsuwan Jarasfah"

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    Synthesis of ZnO/TiO2 spherical particles for blue light screening by ultrasonic spray pyrolysis
    (Elsevier Ltd, 2020) Ratanathavorn Wittawat; Rungruang Rittipun; Modsuwan Jarasfah; Bouhoad Nattaporn; R. Wittawat; Faculty of Science and Technology, Suan Dusit University, Bangkok, 228-228/1-3 Sirindhorn Alley, Bang Bumru, Bang Phlat, 10700, Thailand; email: wittawat_rat@dusit.ac.th
    A broad UVÐvis absorbance covering the blue visible region was obtained by ultrasonic spray pyrolysis of ZnO/TiO2 spherical particles at pyrolysis temperatures of 400 ¡C, 500 ¡C and 600 ¡C. Zinc nitrate hexahydrate and titanium isopropoxide were used as precursors prepared via mixed solution. The morphology characterization and elemental analysis of the synthesized ZnO/TiO2 spherical particles were carried out by a scanning electron microscope equipped with an energy dispersive X-ray spectrometer and by a transmission electron microscope. The crystal structures were characterized by X-ray diffraction (XRD). UVÐvis absorbance spectra were measured by an ultraviolet-visible-near infrared spectrometer. The synthesized particles were confirmed to be ZnO/TiO2 microspheres. The obtained ZnO structure was indicated by XRD analysis to be wurtzite, and two different TiO2 structures were observed; anatase and rutile. The crystal sizes were estimated from Scherrer's equation and ranged from 33.53 to 39.63 nm for the ZnO crystal, and from 5.78 to 59.2 nm for the two TiO2 crystals. The calculated energy band gap of the synthesized ZnO/TiO2 spherical particles ranged from 3.19 to 3.76 eV. Thus, doping of ZnO with TiO2 promoted visible light absorption, providing a broad UVÐvis absorbance that covers the blue light region more efficiently than commercial ZnO. © 2020 Elsevier Ltd