Junchao Tao

Non-Prefabricated Nanocrystal Mesoporous TiO2-Based Photoanodes Tuned by A Layer-by-Layer and Rapid Thermal Process

We describe a flexible and competent solution for fabrication of non-prefabricated nanocrystal mesoporous TiO2-based photoanodes whose thicknesses are tunable from several hundreds of nanometers up to 12.4 microm. The combination of rapid thermal process and layer-by-layer spin-coating is successfully used to manipulate the structure and morphology of non-prefabricated nanocrystal mesoporous TiO2 films. The photovoltaic performances of mesoporous TiO2-based dye-sensitized solar cells depended on the thickness and the annealing temperature of mesoporous photoanodes. We systematically investigated and noted that the non-prefabricated nanocrystal mesoporous TiO2 films approximately 6.3 microm thick annealed at 500 degrees C displayed better features in the short-circuit current density and overall conversion efficiency of mesoporous TiO2-based dye-sensitized solar cells.

TiO2 Nanotube Arrays for Quantum Dots Sensitized Solar Cells

Vertically oriented, highly ordered TiO2 nanotube arrays have attracted considerable attention because of their impressive competence in a variety of applications including solar cells, chemical sensing, photocatalysis and biomedical industry. However, only a few papers reported on the solar cells prepared by combining TiO2 nanotubes and semiconductor quantum dots (QDs) based on composite structures. This paper presents the preparation of TiO2 nanotube arrays for the solar cells based on TiO2 nanotubes and CdSe QDs. The fabrication routes of highly organized TiO2 nanotube arrays synthesized by anodization of Ti foil in electrolyte were described, the performance of TiO2 nanotube arrays on the CdSe QDs sensitized TiO2 nanotube arrays photoelectrodes was investigated, too. The work herein details the effect of fabrication variables anodization time and examines the crystalline nature of the annealed (initially amorphous) samples. The nanotubes have an average inner diameter of 50 nm and a tube thickness of 12 nm. The maximum length of the TiO2 Nanotube we achieved is 9.75 μm. In QDs-sensitized TiO2 nanotube solar cells, CdSe QDs were used as the antenna layer (an absorber material) coating on the surface of titanium foil. Application of nanotube arrays to quantum dot solar cells under sunlight is discussed and compare to the dye sensitized solar cell. The quantum dots (QDs) sensitized solar cells efficiencies can not match dye sensitized solar cell, but it will be a novel way to utilize solar energy in the future.

Temperature dependence of photoluminescence property in BaIn2O4

The temperature-dependent photoluminescence (PL) spectra of BaIn2O4, prepared by coprecipitation, are measured and discussed. Aside from the reported 3.02-eV violet emission, the 1.81-eV yellow emission involved with oxygen vacancy is also observed at room temperature wherein the deep donor level is at 1.2 eV. With the temperature increasing, the peak energies for both emissions show a red shift. Moreover, the yellow emission intensity decreases while the violet emission intensity increases. The temperature dependence of the yellow emission intensity fits very well into the one-step quenching process equation, indicating a fitted activation energy at 19.2 meV.