Design,Synthesis And Characterization Of New Photovoltaic Donor Materials Based On Porphyrin

Compared with traditional crystalline silicon cells and thin-film solar cells,organic solar cells(OPVs)are more concerned because of their low production costs,good performance,easy preparation and environmental friendliness.Although after several decades of development,but until now,the photoelectric conversion efficiency and stability of OPVs is not as good as traditional solar cells.In order to achieve a better efficiency to improve performance,the researchers need to design and optimize the structure of materials and devices,find out their relationship for implementing the application in the near futrue.Porphyrin,phenohiazine,diketopyrrolopyrrole(DPP)and benzothiadiazole(BT)are all widely used in the field of photovoltaic materials because of their good performance.The Porphyrins have a large conjugated structure,good planarity,strong electron transfer ability,and S band(400-500 nm)and Q band(600-700 nm)show strong spectral response.The introduction of phenothiazine in this paper expected to broaden the absorption between those two gaps;DPP has a good film-forming ability,and the plane is also good which benefits to broaden the spectral response range of the material;Benzothiadiazole has a strong electronic absorption capacity,which is conducive to widen the absorption spectrum between 450-700 nm,and red shift the spectrum.In this paper,we designed and synthesized these three groups of organic small molecules and polymers,and applied to organic solar cells.The work was carried out by following:1.Three polymers GP(1-3)with porphyrins and DPP were designed and synthesized.These three polymers showed a good film-forming ability and a good solubility.The embedding of the DPP group broadened the absorption spectrum of the polymers to the near infrared region.Different positions on the porphyrin meso-substituted alkyl group could effectively affect the absorption spectral range of the material and the band gap and thermal stability.2.A series of small organic molecules GM(1-3)based on porphyrins and phenothiazine derivatives were designed and synthesized.These organic molecules showed a good solubility by the introduction of alkoxyl chains and alkyl fork chains;the introduction of phenothiazine broadened the absorption spectrum of porphyrin materials in a sense,which showed strong spectral absorption between 400-600 nm and 650-750 nm;Besides,5 % weight loss of these series of small moleculestemperatures(Td)of all over 300 ?,which were of good thermal stability and had the potential to be photovoltaic materials.3.A series of small organic molecules GM(4-6)based on porphyrins and Benzothiadiazole derivatives were designed and synthesized.The effect of the groups on the performance of small molecules was investigated by changing the alkyl chains at the meso positions of porphyrins.The series of small molecules showed good spectral absorption between 400-550 nm and 600-750 nm;Besides,5 % weight loss of these series of small molecules temperatures(Td)of all over 330 ?,which were of good thermal stability and had the potential to be photovoltaic materials.