Preparation Of Rutile And Anatase TiO₂ Nanowire Arrays And The Application In DSSC

Nowadays,silicon based battery has already been commercialized.,people are still trying to explore new methods of photoelectric conversion,hope to get cheaper and less pollution,stable solar cells.The dye-sensitized solar cell?DSSC?gets more and more attention for the low cost and simple production procession,and more important is the Characteristics of small environmental pollution,which has great potential.The main structure of DSSC includes the the fluorine doped transparent conductive glass,and TiO₂ nanocrystalline porous semiconductor film is on the FTO glass,and the dye sensitizer?currently using N719 in general?is attached to the film.Counter electrode and the redox electrolyte which injected at last.TiO₂ film was grown directly on the treated FTO conductive glass by high temperature and high pressure hydrothermal method.The thin film is composed by one dimensional highly ordered and dense TiO₂ nanorods,which is characterized by high electron transfer efficiency and low electron recombination probability.To increase the specific surface area of the film while maintaining the advantage of one dimensional material is the focus of the study.In this paper,the hydrothermal synthesis of TiO₂ nanowire arrays is studied.?1?The study use of butyl acetate?TBOT?as titani?m source,hydrochloric acid and deionized water solution under high temperature and high pressure.TiO₂ nanorods film generally reached the highest 3,4?m which directly grow on the FTO glass surface.The surface area of the film thickness is too small,and the smooth surface of the nanorods also leads to the deficiency of the dye adsorption amount.Using TiCl4 as the titani?m source can increase the length of the nanorods and increase the thickness of the film,thereby increasing the surface area of the film.Then the chemical etched by HCl is effect on the film to increase the roughness of the surface.The high specific surface area and high electron transport efficiency of rutile crystal is obtained.At the same time,to keep the film's thickness and not dorp from the FTO conductive glass,deposited a layer of TiO₂ about 100nm dense layer on the conductive glass.The experimental results show that it is effective to prevent the detachment of the film.The films were obtained from 0.5?m to 13?m at different reaction times.And the DSSC based on 13?m thick films,with chemical etching of different time,the highest photoelectric conversion efficiency reached 4.69%.Compared to no etching of films,the efficiency of dye sensitized solar cell from 2%enhanced 134.5%.Comparing to the same thickness of P25 film ?=3.26%photoelectric conversion efficiency rate increase 40%.?2?Using potassi?m titanyl oxalate as titani?m source,DEG and DI water solution under high temperature and high pressure at 180?,on FTO glass surface growth can get anatase nanorods array.In the hydrothermal reaction system,a lot of DEG decreases the solubility,resulting in the anatase crystal growth and division of the branched structure,and the nanorods have the characteristics of high specific surface area and high electron transport efficiency.Different reaction time can obtain different morphologies,The results shows that in the initial reaction only formed the trunk of nanorods,with extension of reaction time many glitches structure formed on the trunk.Finally,the formation of the forest like nano array,branched structure film already got.The thickness of the film can achieve 20?m.Then I study the effect of changing the proportion of water and ethylene glycol on nanowire arrays from 1:1.5 to 1:3.5.Found that with the increase of water content,the diameter of nanowires decreases,and the diameter of the branch structure of nanowires decreases,and the length becomes shorter,and the number becomes bigger,and the specific surface area is increased.The photoelectric conversion efficiency was tested by simulating the light source,and the maximum efficiency ?= 4.95%was found when the volume ratio of water to DEG was 1:1.5.