Papers by Author: Jian Jun Liao

Abstract: Here we report on regioregular poly-(3-hexythiophene) (P3HT) organic field-effect transistors (OFETs) with various metal electrodes: pristine Au, pristine Cr, and Cr/Au. Compared to the performance of OFETs using different electrodes, the OFETs with Au electrode have better mobility (μ = 0.0090 cm²/Vs) and larger current at the same source-drain voltage and gate voltage. The enhancement of the device performance with Au electrode can be attributed to a small contact resistance and a small barrier height to P3HT for hole carrier injection.

Abstract: In the present work, we demonstrated a facile process to prepare an open-ended high aspect-ratio TiO2 nanotube films through separating the anodic TNT array from the Ti substrate by a small reverse bias and opening the tube bottom by a chemical etching. The possible mechanisms of film detachment and pore opening processes have been briefly discussed. Such a process allows controlling the open-ended morphology by the straightforward chemical etching, which shows great potential in many applications, such as flow-through photocatalytic reactions, biofiltration, and diffusion controlling, and so on. An example using the open-ended TNT films is finally given as a flow-through photocatalytic reactor. The photocatalytic film has been shown to have multiple functions such as physical separation of contaminants, filtration, and decomposition of organic pollutants during diffusion.

Abstract: Titania nanotube arrays were fabricated in deionize water and glycerol mixed electrolyte containing a certain amount of NH₄F. Three different polishing methods were used for pretreatment of Ti substrates: polished by hand with abrasive paper, by polishing machine, or by chemical polishing fluid (HF:HNO₃=1:4, in volumetric ratio). The morphology of three different samples were imaged by scanning electron microscopy, and their photoelectrical properties were studied as well. Experimental results showed that Titania nanotube arrays grown on the Ti substrate and polished by polishing fluid has highly-ordered and well-defined nanotube structure. The effects of anodization potential and duration on synthesis of highly-ordered TiO₂ nanotubes were also studied in this paper. Both the layer thickness and nanotube diameter linearly increase with the increasing potential. The layer thickness also increases with prolongation of anodization time. By optimizing the preparation conditions, we can successfully control the geometrical structure of TiO₂ nanotube arrays with diameters in the range between 50 and 200 nm and the layer thickness between 800 and 2000 nm.