摘要
Reducing the voltage loss(Vloss)is a critical factor in optimizing the open-circuit voltage(Voc)and overall power-c on version efficie ncy(PCE)of polymer solar cells.In the current work,by designing a novel electron-accepting unit of coronenediimide(CDI)and using it as the main functional building block,a new polymer acceptor CDI-V is developed and applied to fabricate all-polymer solar cells.Compared with the perylenediimide-based polymer acceptors we previously reported,the current CDI-V polymer possesses a noticeably elevated lowest unoccupied molecular orbital(LUMO).Thereby,by virtue of the enlarged energy gap between the donor HOMO and acceptor LUMO,a high Voc value of 1.05 V is achieved by the all-polymer photovolatic device,along with an impressively low Vloss of 0.55 V.As remarkably,in spite of an extremely small LUMO level offset of 0.01 eV exhibited by the donor and acceptor polymers,effective charge separation still takes place in the allpolymer device,as evidenced by a proper short-circuit current(Jsc)of 9.5 mA·cm^-2 and a decent PCE of 4.63%.
基金
the National Natural Science Foundation of China(Nos.21674001,21925501,and 21790363)
the High-performance Computing Platform of Peking University for the computational resources
the Hong Kong Research Grants Council(Nos.T23-407/13 N,N_HKUST623/13Z 16305915,16322416,and 606012)
HKJEBN Limited,HKUST presidents office(No.FP201)
Hong Kong Innovation and Technology Commissi on(Nos.ITCCNERC14SC01 and ITS/083/15).
