| Organic semiconductors enable new generation of photovoltaics with unique advantages,such as light-weight,low-cost,solution processability and flexibility.With the strong driven of novel organic semiconductor developments,perovskite solar cells and organic solar cells are not far away from commercial applications.In this thesis,several most advanced organic semi-conductors were summarized in the introduction,followed with three novel organic semi-conductors we developed.We designed and synthesized a dopant-free hole transporting material Trux-OMeTAD based on disk-like truxene core for perovskite.solar cells.The planar structure promotes the intermolecular π-π stacking which further increases the hole mobility up to 10-3 cm2/Vs.The perovskite solar cells fabricated upon the dopant-free Trux-OMeTAD hole transporting layer showed an excellent efficiency as 18.6%with negligible hysteresis,which was one of the best hole transporting materials for perovskite solar cells.We also developed two non-fullerene acceptors based on S,N-heteroacene fused-ring,where the introducing of sp2-N atom could enhance the intramolecular charge transfer and conjugation length.The bulky heterojunction organic solar cells based on PBDBT/SN6IC-4F active layer achieved 13.2%PCE with only 0.54 eV energy loss,proving the superior designing of pyrrole substituted fused-ring structure.To cut down the high cost of the synthesis,we developed a non-fused-ring acceptor based on EDOT fragment which could introduce interaction between oxygen atom and sulfur atom so that the conformation of these aromatic rings could be fixed in one plane.And the synthetic route of EB4F was well modified for low-cost fabrication.The devices based on PBDBT/EB4F active layer showed a PCE of 6.89%.In summary,three novel organic semi-conductors were developed for perovskite and organic solar cells,the relationships between structures and efficiency were well defined,and the designing strategy could be good examples for further research. |
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