Controllable Preparation Of Doped Titanium Dioxide Nanowires And Application In Photodetectors

Titanium dioxide(TiO₂)is a critical wide-bandgap semiconductor material(?3.0-3.2 e V).Benefiting from its low-toxicity,non-toxic,and stabile physical/chemical properties,it is widely used in various fields such as ultraviolet detection,photocatalysis,renewable energy,and environmental protection.However,the weak absorption of visible light restricts the application of TiO₂,especially in solar cells and as photocatalyst.In recent years,in order to improve the spectral absorption of the whole solar band by TiO₂,researchers have mainly adopted the following three ways to improve its performance:(1)Morphology control:the morphology of low-dimensional nanowires have the ability of electronic transmission;(2)Doping ion:impurity level is introduced into the TiO₂ band gap to adjust the energy band structure,so as to promote the absorption of visible light and improve the light response efficiency of TiO₂ to sunlight;(3)Controlling the formation of different crystal types:TiO₂with different crystal types have differences in crystal structure and energy band structure.However,the implementation of all three types of regulation is rarely reported.On this basis,this paper explores a new synthesis method,and focuses on the effects of doped transition metal elements(Cu,V,Mo,In and Sn)on the morphology and photoelectric properties of TiO₂.The specific contents are as follows:(1)Pure titanium dioxide was taken as an example.Firstly,electrospinning technology is used to prepare uniform transition metal-doped titanium dioxide.Secondly,pure/doped nanofibers obtained by electrospinning are used as precursors,the microwave assisted hydrothermal method not only realizes the preparation of ultra-long TiO₂ nanowires,but also saves a lot of time for preparing materials.Finally,by controlling the calcination temperature,the transition metal-doped TiO₂ of different crystal types is obtained.(2)Through a series of detailed characterization techniques,the influence of different doping ions on TiO₂ was explored.Due to the introduction of transition metal ions,the impurity levels and defect levels resulting from a large number of oxygen vacancies were formed,which realized the regulation of the TiO₂ energy band structure.Further studies have shown that the introduction of doped ions will also inhibit the phase change reaction of TiO₂.(3)The optical sensor based on pure/doped TiO₂ nanowires was introduced.The photoelectric conversion performance of the sensor devices based on different doped ions is compared and analyzed,and it was found that Cu and V-doped TiO₂ nanowires shortened the recovery time of photosensor devices,and the devices prepared by Sn and Mo-doped TiO₂ nanowires had improved under blue light.