The Synthesis Of Organic Sensitizers Featuring Thiophene Derivativesbased Donors And Application In Solar Cells

The energy problem is a huge obstacle to the development of the world,solar energy as an inexhaustible supply of energy should be used efficiently.In recent years,dye sensitized solar cells have developed rapidly,and the development of efficient and stable photosensitive dyes is the focus of research in this field.We designed a series of dyes with high conjugated thiophene derivatives as the donor,which can improve the stability of the battery in the premise of excellent photovoltaic performance.Thiophene derivatives,including thieno[3,2-b][1]benzothiophene(TBT),benzo[b]thiophene(BT),2-phenylthieno[3,2-b]thiophene(PTT)and 2-phenylthiophene(PT),have been introduced as donor for construction triarylamine organic dyes(M52,M53,M56,M57 and M52A).The absorption,electrochemical,photovoltaic properties and stability of these dyes are systematically investigated and compared with the reference dye(M55)whose donor composed of the hexyloxybenzene(HOB)unit.It is found that introducing of TBT,BT,PTT or PT donors positive shifted the HOMO and LUMO levels of organic dyes,providing a large driving force for regeneration and reducing the energy loss in electron injection.In addition,we found that M52 contains the TBT unit exhibited a better photovoltaic performance and photo stability as compared to the reference dye.In contrast,M53 displays the lowest efficiency and stability among these dyes,indicating that the BT unit is not a good building block for donor.Interestingly,upon the incorporation of the mixed donor(TBT-HOB),M52 A achieves a desirable driving force for regeneration without a loss in light absorption,thus resulting in a further improved photovoltaic performance with respect to that of M52.This work demonstrated that introducing the thiophene derivatives based donor is a good strategy for tuning the energy level and thereby enhancing the efficiency of devices.