TAILIEUCHUNG - Abnormal photoluminescence of TIO2 nanocrystals (nanoparticles and nanotube arrays)

In this paper we report new abnormal photoluminescence results of TiO2 nanocrystal particles and nanotube arrays. Photoluminescence spectra were recorded for TiO2 nanocrystal particles and nanotube arrays that were synthesized by a wet chemical route and the electrochemical anodization, respectively. It was found that the TiO2 nanocrystal with small size of 5-8 nm no emitted when excited by a laser beam of 325 nm, in contrary it emitted when excited by laser beam of 442 nm. | Communications in Physics, Vol. 24, No. 3 (2014), pp. 275-281 DOI: ABNORMAL PHOTOLUMINESCENCE OF TIO2 NANOCRYSTALS (NANOPARTICLES AND NANOTUBE ARRAYS) LY NGOC TAI, TO LE HONG HOANG, AND LE VAN HONG Institute of Materials Science, Vietnam Academy of Science and Technology E-mail: Received 31 July 2014 Accepted for publication 15 September 2014 Abstract. In this paper we report new abnormal photoluminescence results of TiO2 nanocrystal particles and nanotube arrays. Photoluminescence spectra were recorded for TiO2 nanocrystal particles and nanotube arrays that were synthesized by a wet chemical route and the electrochemical anodization, respectively. It was found that the TiO2 nanocrystal with small size of 5-8 nm no emitted when excited by a laser beam of 325 nm, in contrary it emitted when excited by laser beam of 442 nm. The TiO2 nanotube arrays exhibit a similar emission behavior. The nanotube arrays weakly emitted when excited by a laser beam of 325 nm and more strongly emitted when excited by a laser beam of 442 nm. The obtained results have been explained by a two-step exciting model and supposed to be related with the size effect of nanocrystal and it is an experimental evidence to believe that the TiO2 nanoparticles and nanotube arrays are applicable for photo-catalysis under sun light. Keywords: TiO2 nanocrystals, TiO2 nanotube arrays, absorption, luminescence. I. INTRODUCTION Titanium dioxide TiO2 has attracted the world-wide scientists and technologists because of its huge application possibilities in pigments, photocatalysis, solar cells, gas sensors, and water splitting [1–3]. It is well known that TiO2 is a semiconductor having large energy band gap ( eV, eV for anatase and rutile phase, respectively). So TiO2 is photoactive only to the light in the wave-length range shorter than 400 nm. It means this material has law photo-electronic efficiency under sun light due to the contribution of .

• Vật lý
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• Abnormal photoluminescence of TIO2 nanocrystals
• Nanoparticles and nanotube arrays
• The electrochemical anodization
• Similar emission behavior
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