摘要
To clearly show how important the impact of side chains on organic solar cells(OSCs)is,we designed three acceptors IDIC-CxPh(x=4,5,or 6)via subtle side-chain regulation.Despite this small change,significant distinctions were detected.IDIC-C4Ph devices achieve an optimal efficiency of 13.94%under thermal annealing,but thermal-assistant solvent-vapor annealing hugely suppresses the efficiencies to 10%.However,the C6Ph side chain endows extremely disordered stacking orientations,generating moderate efficiencies of~12.50%.Excitingly,the IDIC-C5Ph affords an unexpected two-channel p-p charge transport(TCCT)property,boosting the fill factor(FF)by up to 80.02%and efficiency to 14.56%,ranking the best among five-ring fused-ladder-type acceptors.Impressively,the special TCCT behavior of IDIC-C5Ph enables 470 nm thick-film OSC with a high FF of up to 70.12%and efficiency of 13.01%,demonstrating the great promise in fabricating largescale OSCs.
基金
The authors are deeply grateful to the National Natural Science Foundation of China(21502205,51773220,51703104,and 51873227)
DICP&QIBEBT(UN201805)for financial support.X.C.B.deeply thanks the Youth Innovation Promotion Association CAS(2016194).R.Q.Y.gives thanks to the“Chutian Scholar Program”of Hubei province.The work is also supported by the Dalian National Laboratory for Clean Energy for Clean Energy(DNL),CAS.The authors thanks Prof.Chunming Yang from the Shanghai Synchrotron Radiation Facility for useful discussions.
