Enhanced field emission from Ti3+ self-doped TiO2 nanotube arrays synthesized by a facile cathodic reduction process

A facile strategy of cathodic reduction has been developed to successfully prepare Ti3+ self-doped TiO2 nanotube field emitter arrays (TNAs). This strategy significantly reduces the requirements of instruments and resources compared to the conventional strategies and can controllable introduction of Ti3+ sites (oxygen vacancies) into TNAs with morphology retention. The introduced Ti3+ sites (oxygen vacancies) served as electron donors, can substantially improve the conductivity and decrease the work function of TNAs. Importantly, compared to pristine TNAs, the Ti3+ self-doped TNAs show enhanced field emission (FE) properties including sharply decreased turn-on field from 12.49 to 2.67 V/μm and large FE current density of 4.31 mA/cm2 at 4.45 V/μm.