Preparation And Performance Study Of Transparent TiO₂ Photoanode

As an inexhaustible renewable energy,solar energy is considered as the most important and reliable clean energy to solve the increasing energy demand.Quantum dot sensitized solar cells（QDSSCs）have good thermal stability and humidity stability,and become one of the potential solar cells due to the advantages of band gap adjustability and quantum confined area effect.Due to the rapid development of society,the requirements of solar cells are gradually increasing,we need to ensure the solar power generation,and they should have a considerable degree of transparency at the same time.In order to meet the needs of smart home and modern buildings,the development of new transparent solar cells has become increasingly urgent.TiO₂has been widely used in the research of photoanode materials for quantum dot sensitized solar cells due to its excellent characteristics such as good photostability,low price and non-toxicity.It is very important to prepare TiO₂photoanode with sufficient transparency,good electron transfer ability and good adsorption effect on quantum dot sensitizer.In this paper,we prepared transparent TiO₂photoanode by tetrobutyl titanate and rutile,and investigated its application in QDSSCs.The details are as follows:（1）TiO₂thin film photoanode was prepared by spin-coating method.Cu S with superior performance was selected by comparing C counter electrode and Cu S counter electrode.Cd S/Cd Se co-sensitization and simple Cd S sensitization were compared in the sensitization process,and Cd S/Cd Se co-sensitization was selected.TiO₂thin film photoanode was prepared by mixing slurry of tetrabutyl titanate and rutile powder in different proportions.The good transparency of TiO₂photoanode was proved by the photo and transmittance more than 60%.With the increase in the molar ratio of rutile,the particle distribution on the TiO₂chip became much denser.The adsorption effect of quantum dot sensitizer is better,which leads to the improvement of photoelectric properties,but when there is too much rutile powder,the performance will decline.The optimal ratio was 79:21,Jsc,Voc,FF and PCE were 16.33 m A/cm²,0.61 V,38.01%and 3.55%,respectively.（2）TiO₂nanowires were prepared by hydrothermal method.TiO₂nanowires were mixed with the paste used in the experiment in the previous chapter to obtain a new paste and prepare a transparent photoanode.Through morphology characterization,we found that TiO₂nanowire was attached to or between TiO₂sheets,and TiO₂nanowire could directly realize electron transmission.Therefore,the addition of TiO₂nanowire improved the electron transmission properties,thus realizing the performance improvement.By comparison,the optimal doping amount of TiO₂nanowires was 10:1 group,and the PCE value increased from 3.55%to 3.79%.After that,we adopted the method of spin coating twice.In the second spin coating,a small amount of rutile was used with a large amount of TiO₂nanowire to achieve the adhesion of sufficient amount of TiO₂nanowire on the photoanode.A series of tests and analyses were conducted on the obtained photoanode,and it was found that the performance was significantly improved when the molar ratio of rutile powder to TiO₂nanowire changed from 1:10 to 1:20,while when the molar ratio reached 1:30,the basic structure of the film was destroyed due to excessive TiO₂nanowire,resulting in large TiO₂gap.More defects cause electron holes to recombine easily,resulting in worse photoelectric performance.When the molar ratio of rutile powder to TiO₂nanowires was 1:20,the optimal performance was achieved,and the PCE increased from 3.79%to 4.01%in the control group.