Synthesis,Morphology Control And Photoelectric Properties Of Non Fullerene Double Cable Conjugated Polymers

Single-component organic solar cells(SCOSCs)have excellent stability because the donor/acceptor components of the photosensitive layer materials are chemically bonded,allowing precise regulation of the phase separation size,reducing self-aggregation,and enabling intra-chain charge separation and transport.The power conversion efficiency of SCOSCs is still low when compared to other organic solar cells,such as two-component or threecomponent solar cells.Because of this,current research is concentrated on creating novel molecular structures or altering synthetic methods.Both doublecable conjugated polymers(DCPs)and block polymers are important singlecomponent materials,but DCPs have well-defined structures,making it easier to adjust the morphology by constructing appropriate molecular structures to achieve good performance.In this paper,a series of DCPs with naphthalene diimide(NDI)acceptors and non-fused ring electron acceptors as conjugated polymer side chains were synthesized to enhance the photovoltaic efficiency of organic solar cells through optimizing the chemical structure and donor/acceptor ratio.The specific research findings are presented below.1.A series of random copolymers with different NDI side chain contents were synthesized to investigate the effect of acceptor side chain content on the photovoltaic performance of SCOSCs.The NDI content was adjusted by random copolymerization to optimize acceptor stacking and achieve efficient charge separation.As the NDI content increased,the polymer’s absorption peak red-shifted,which helped to improve the main chain aggregation and promote charge generation in the solar cell.Additionally,when NDI side chain units were introduced,the π-π stacking distance of the polymer decreased,the crystallinity increased,and efficient charge transport channels were formed.As a result,the power conversion efficiency of the solar cells increased from 0.17%(PCl BDBT)to 7.97%(JP02).2.Non-fused ring electron acceptors were introduced into double-cable conjugated polymers by adjusting the degree of end-group fluorination to synthesize three types of polymers,C6-0F,C6-2F,and C6-4F.These polymers were applied to single-component organic solar cells to investigate the effect of fluorine atom content on the photovoltaic performance of SCOSCs.The introduction of end-group fluorine atoms not only broadened the absorption wavelength range of the polymers and reduced the band gap width,but also reduced the interlayer distance and π-π stacking distance of the polymers,enabling the formation of a more compact stacking structure and improving charge transport efficiency.By optimizing the additives and annealing temperature,the energy conversion efficiency of the device gradually increased from 4.07%(C6-0F)to 6.54%(C6-2F)and then to 7.47%(C6-4F).