Preparation And Study On The Photovoltaic Performances Of Organic Dyes And Hole Transporting Materials Based On Triphenylamine

Energy shortage has becoming a serious problem in the society.The exhaustion of fossil fuel sources day by day,the requirement of new energy has been an ever increasingly pressing one.However,advanced energy materials and photovoltaic technology have brings some hopes for this issue.In the situation of modern industrial pollution and fog and haze increasingly seriously now.Film solar cell has not pollution and also can solve the energy crisis partly.Moreover,it need only very thin material and can make flexible device,which can save costs.Dye sensitized solar cells(DSSCs)has much more twenty years history to date.The best power conversion efficiency has achieved 14.3%.The most important issue is researching for a new high efficiency material.Moreover,perovskite solar cells(PVSCs)have a rapid development in recent years.Which is derive from DSSCs and they have similarity.The power conversion efficiency of PVSCs has risen from 3.8% to 22.1% in recent years.Which mostly attribute to the improvement of morphology of perovskite layer,the optimizations of electron transfer layer(ETL)and hole transport layer(HTL)and interfacial modification.Triphenylamine has good electron-donating and hole transport abilities.Therefore,it is an ideal donor unit.The detailed contents of this paper as follows:1.A new organic dye with conjugated side group on the thiophene ?-bridge was designed and synthesized for DSSCs,which is based on the triphenylamine(TPA)as the donor unit,thiophene with thiophene phenoxazine(POZ)derivatives as the conjugated side group,and cyanoacetic acid as the acceptor unit.Compared with the dye with conjugated ?-bridge of thiophene with conjugated alkadiene,the photophysical properties have been tested and found that POZ derivatives dye molecule have higher molar extinction coefficient.Subsequently,the electrochemical and photovoltaic properties also has been studied and found that it has matching energy level and excellent photovoltaic performance.Because of the existing of H-type aggregation,we got power conversion efficiency(PCE)of 4.88% in the addition of co-adsorption chenodeoxycholic acid(CDCA).2.Designed and synthesized two new small molecule materials W-1 and W-2,which is TPA as double end groups and the bithiophene and pyrrole,bithiophene and cyclopentadiene as the core,respectively.In addition,we used them as the hole transporting materials(HTM)in perovskite solar cells.Compared with the common HTM Spiro-OMeTAD,W-1 and W-2 have the advantages of simpler molecular structure and synthesize route.The electrochemical property has been discussed in detail as follow chapter.The results indicated that they have appropriate HOMO energy,which ensured the injection of holes efficiently.Moreover,the solubility is superior and film forming property is excellent.Then,photophysical and photovoltaic properties also have been discussed,and found that they have analogous property with Spiro-OMeTAD.It has practical value for the development of high performance HTM.3.With the research object of PVSCs device,we discussed the influence of the thickness of mesoporous layer.We experiment six different concentrations of the TiO2 paste,and get six thicknesses of mesoporus layer film.Through the analysis of surface morphology,it is found that excessive concentration will result in bad film forming of TiO2 mesoporous layer,and then result in an inhomogeneous perovskite surface and low coverage.However,by the analysis of photophysical properties found that the thinner mesoporous layer would reduce the light absorption,and increase the hysteresis effect.In conclusion,the thickness of 170 nm shows best performance,its PCE up to 17.8% and hysteresis factor as little as 7%.The result indicated that an appropriate thickness of mesoporous layer is essential for device performance.