The Study Of Preparation With Low Temperature And Photoelectric Properties Of Antase TiO₂ Transparent Films

In recent years,as an important semiconductor material,TiO2 thin films have been widely used in photocatalysis,solar cells,gas sensors,photodetectors and other fields due to their excellent photoelectrochemical properties,low cost,simple preparation and low toxicity.At present,most of the methods for preparing anatase crystalline TiO2 with excellent photoelectric properties need to be annealed with high temperature above 350?.With the development of science and technology,all kinds of electronic devices such as organic light-emitting diodes,solar cells,photodetectors tend to be wearable flexible materials.The flexible substrates such as polyethylene terephthalate(PET)and polyimide(PI)are usually organic material,which can not withstand high temperature.Therefore,reducing the preparation temperature of TiO2 crystal thin films,which make the temperature below 200? and lower is an important direction for the future development of TiO2 thin films.In this paper,transparent anatase TiO2 thin films with good photoelectric properties were successfully prepared by liquid phase deposition and magnetron sputtering at lower temperature.The application of TiO2 thin films in ultraviolet photoelectric detection was studied,and the photoelectric detection performance of the films was improved by doping modification.Specific research contents are as follows:(1)Transparent anatase-type TiO2 crystal films were prepared on ITO/PET substrates by simple liquid deposition method,and then photoelectrochemical cell-type(PECC)self-powered ultraviolet detectors were prepared by using I-/I3-electrolyte.The effects of water bath temperature and solution concentration on the properties of TiO2 thin films were studied.It was found that with the increase of water bath temperature and solution concentration,the photocurrent density of the samples increased first and then decreased.The results show that the film has good crystallinity,uniform and compact surface morphology and an average transmittance of about 75%when the water bath temperature and solution concentration are 75?and 0.04 mol/L,respectively.At this time,the photoelectric detection performance ofthe sample is relatively optimal.The photocurrent density can reach 29.81?A/cm2,the rising time and falling time are 0.095s and 0.052s,respectively,the responsiveness can reach 0.199A/W,and the sensitivity is 64.(2)In order to farther improve the photoelectric detection performance of the films,the TiO2 films were modified by metal doping.Transparent anatase-type TiO2 crystalline thin films doped with Nb were prepared by liquid phase deposition.According to XPS,Nb was successfully doped into the interior of TiO2 crystal.Compared with the undoped TiO2 film,the photoelectric properties of doped TiO2 films have been significantly improved.With the increase of doping concentration,the photoelectric detection performances of the samples first increased and then decreased.When the Nb doping concentration is 2%,the photoelectric detection performance of the sample is the best,the response and sensitivity are 0.456A/W and 325,the rising time and falling time are 0.077s and 0.048s,respectively.Subsequently,TiO2 films doped with other metal elements(Sr)were successfully prepared by the same method,which is helpful for the study of TiO2-doped thin films at low temperature.(3)Nb-doped transparent anatase-type TiO2 crystals with good transmittance and photoelectric properties were successfully prepared by magnetron sputtering at the temperatures below 200?.It was found that the annealing temperature and doping concentration have significant effects on the crystal structure and photoelectric properties of the TiO2 films.When the annealing temperature is 200�C and the doping power is 50W,the responsiveness of the sample can reach 11.27A/W,the sensitivity is 815,the rising time is 0.12s,and the falling time is 0.069s.