Photoluminescence And Photocatalytic Properties Of Rare-earth Doped Molybdenum Trioxide Nanomaterials

Photoluminescence and photocatalytic properties are two important and complementary optical properties of the semiconductor oxide nanomaterials. For the wide bandgap semiconductor, photoluminescence caused by rare-earth doped make it has broad market prospects and development potential in the field of optical communications and flat panel displays, and it also is an excellent candidate for water treatment because of its photocatalysis property. Therefore, it is very meaningful to study the optical properties of wide bandgap semiconductor materials. In this thesis, we study the properties of rare-earth doped molybdenum trioxide. The details are described as follow。For the photoluminescence properity, the rare-earth doped molybdenum trioxide nanofibers were prepared by electrospinning method. After analysing the X-ray diffraction (XRD) and Raman spectra, we found that rare earth doped can change the crystalline and preferred orientation growth of molybdenum trioxide (MoO3), and it also can enhance its Raman singal. As the light-emitting enhanced matrix, MoO3is a excellent rare-earth doped luminescent substrate and can effectively enhance the luminous efficiency of erbium ion (Er3+) and terbium (Tb3+) dopants. Then, the europium (Eu3+) doped MoO3nanoparticles were prepared by thermal decomposition method. The doped of Eu3+also can change the XRD and Raman singal of MoO3substrate, but MoO3has very weak influence to enhance the luminous intensity of Eu3+ion.For the photocatalysis properity, undoped MoO3nanoparticles were prepared by thermal decomposition method. And then the samples were further terated by calcined in air at different temperatures. After calcination, the crystalline and the grain size of MoO3nanoparticles are increased when the temperature below600℃, and the crystalline phase was changed after the temperature reached700℃. The MoO3nanoparticle has no luminescent signal between400-700nm, and the calcination treatment has a little influence for its luminescent intensity. The photocatalysis property of MoO3enhanced after calcined at high temperature, unless the temperature reached700℃. Because the quadrature phase is the stability phase when the temperature is higher than700℃, the photocatalytic activity of MoO3nanoparticles is reduced because of the phase change. And then the influences of Er3+and In3+doped were studied by test the photocatalytic activity of doped MoO3nanoparticles. The experiment results confirm that the doped Er3+cannot change the crystalline of MoO3particles, but it can make the doped MoO3has light-emission peak in the visible region, which result in the enhancement of the photocatalytic activity. But if the intensity of dopants is too high, its luminescent properties would reduce and the photocatalytic activity decreased synchronously. For the In3+doped MoO3nanoparticles, the photocatalytic activity reduced with the increasement of dopant intensity, because the In3+only act as recombination centers during the photocatalysis test.In summary, the luminescence intensity of some rare-earth ion would be enhanced, but others would not when the MoO3as rare-earth doped luminescent substrate. And a certain amount of the rare-earth doped can enhance the luminescence intensity of MoO3sbustrate in visible region, which can improve the photocatalytic activity at the same time.