Investigation Of TiO₂ Applied In Organic-inorganic Hybrid Solar Cell

Organic solar cells(OSCs)have become the focus of the research owing to its advantages of simple preparation method and high power conversion efficiency(PCE).But the further development of the OSCs has been greatly limited due to poor chemical stability and short lifetime.Thereby,an inverted device structure is designed and an mental oxide is inserted as the transport layer for improving the stability and lifetime of the devices.Molybdenum oxide(MoOx)films are suitable as the hole transport layer(HTL)of the inverted OSCs because of their high work function and good stability.Titanium dioxide(TiO2)thin films have been acted as the good electron transport layer(ETL)materials selection due to good chemical stability,high optical transmittance,low cost and suitable for large-scale production.In this thesis,a sequencial researches have been carried out under the above-mentioned background.The main results are as follows:1.We have presented an organic polymer-fullerene solar cell with MoOx HTL prepared by Direct Current magnetron sputtering(sMoOx)and thermal evaporation(eMoOx),respectively.Compared with that of eMoOx film,the sMoOx film shows a better performance of morphology,the size of the eMoOx grain is small and distributed regularly.These advantages improve the contact performance between the transport layer and active layer,which is benefit for carrier transport and reduced the carrier recombination.Also,the optical transmittance of sMoOx film is higher,which is resulted in enhanced absorption of the active layer.The PCE of the OSCs is higher with sMoOx that compare with eMoOx.2.The performance of the TiO2 film and devices by doping La3+ are studied.The La3+ inhibits the growth of the grain size and improve the compactness of the film.The performance of the interface and carrier transmission are improved with the decrease of surface roughness after La3+ doped.The 0.50mol%La-TiO2 film shows higher optical transmittance that compare with bare TiO2 film,leading to an increase absorption of P3HT:PCBM,The PCE of the device with TiO2 film as ETL is increased from 1.45%to 2.45%after 0.50 mol%La3+ doped.3.The OSCs based on PTB7:PCBM with La-doped TiO2 film as ETL are studied.The Jsc of the device with TiO2 as ETL is improved after 0.50mol%La3+ doped,which leads to the PCE is increased from 3.70%to 4.51%.The research of this article lays a foundation for the preparation of the high efficiency organic-inorganic solar cell.