Low-temperature liquid phase reduced TiO 2 nanotube arrays: synergy of morphology manipulation and oxygen vacancy doping for enhancement of field emission

The partially reduced TiO 2 nanotube arrays (TNAs) are prepared via an uncomplicated and low-cost liquid phase reduction strategy using NaBH 4 as the reducing agent. By controlling and adjusting the reduction temperatures from 30 to 90 °C, the reduction treatment can not only change their surface morphology but also introduce oxygen vacancies into them, resulting in an optimized morphology, elevated Fermi-level, reduced effective work function and improved conductivity of the TNAs. Meanwhile, the thermal and long-term stability of oxygen vacancy are also investigated, indicating that the oxygen vacancies retain long-term stability from room temperature up to 150 °C. More interesting, partially reduced TNAs show drastically enhanced field emission (FE) performances including substantially decreased turn-on field from 18.86 to 1.53 V μ m −1 , a high current density of 4.00 mA cm −2 at 4.52 V μ m −1 , and an excellent FE st...

Xu-Qiang Zhang, Jian-Biao Chen, Cheng-Wei Wang, Ai-Zhen Liao and Xiao-Feng Su

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