Synthesis And Properties Of Organic Small Molecule Photovoltaic Materials Based On Rhodanine And Trithiophene

Photovoltaic small moleculars?SM-OPV?have attracted considerable attention due to their unique advantages of well-defined structures,easier purification and better batch-to-batch reproduction in properties.This paper introduces the development of organic photovoltaic electronic donor materials based on several typical acceptor units and the research status of organic solar cells.In order to further study the relationship between the molecular structure of the donor material and the photovoltaic properties and explore the molecular design rules of narrow bandgap and efficient small molecule organic photovoltaic electronic donor materials.Their molecular structures were characterized by 1H NMR,TOF-MS and elemental analysis.Their thermal property,optical properties,electrochemical properties and bulk heterojunction photovoltaic properties of these materials were investigated.The research results are as follows:?1?Three A-?-Ar-?-A type organic photovoltaic electronic donor materials were designed and synthesized,in which 1,4-difluorobenzene,furan and benzene were used as central Ar groups,2-?1,1-dicyanomethylene?rhodanine?DRCN?as terminal Ar group,5-vinyl-trithiophene?3T?were used as ?-bridged.The effect of the central Ar groups and intramolecular hydrogen bonds on optical properties,electrochemical properties and photovoltaic performance were systematically studied.It was found that SM of?DRCN3T?2Ox with furan as central Ar unit exhibited best photovoltaic properties.The maximum power conversion efficiency?PCE?of 2.12%with a short circuit current(J_sc)of 4.71 mA/cm²,an open circuit voltage?Voc?of 0.87 V and a fill factor?FF?of 51% was obtained in the?DRCN3T?2Ox based BHJ-OPVs.?2?Two A-?-Ar-?-A type organic photovoltaic electronic donor materials were designed and synthesized,in which the larger planarity naphthylene?Nap?and anthrylene?Ant?were used as central Ar groups,DRCN as terminal A group,3T were used as ?-bridged.The effect of the central Ar groups on optical properties,electrochemical properties and photovoltaic performance were systematically studied.As a result,photovoltaic properties were remarkably improved in these SM/PC71 BM based solution-processing organic solar cells?OSCs?by enlarging Ar units in?DRCN3T?2Ar.The highest power conversion efficiency of 5.15% with a short-circuit current density of 11.34 m A/cm²,an open circuit voltage of 0.88 V and a fill factor of 54% was obtained in the?DRCN3T?2Ant based device.?3?Three classes of D-A-D,D-A-D-A-D and A1-D-A-D-A-D-A1 types low band-gap SMs and oligomers used as photovoltaic donor materials were designed and synthesized,in which 3T were used as D groups,?5,6?-difluorobenzothiadiazole were used as A groups,3-octylrodanine were used as terminal A1 groups.The effect of molecular configuration,the central D groups on photovoltaic performance was systematically studied.It was found that R9TBT4 F of A1-D-A-D-A-D-A1 type shows the best photovoltaic performance.The maximum power conversion efficiency of2.43% with a short circuit current of 4.63 mA/cm²,an open circuit voltage of 0.81 V and a fill factor of 65% was obtained in the R9TBT4F-based BHJ-OPVs.