Polymer solar cells with an inverted device configuration using polyhedral oligomeric silsesquioxane-[60]fullerene dyad as a novel electron acceptor

A polyhedral oligomeric silsesquioxane-[60]fullerene （POSS-C60） dyad was designed and used as a novel electron acceptor for bulk heterojunction （BHJ） polymer solar cells （PSCs） with an inverted device configuration. The studies of time-resolved photoinduced absorption of the pristine thin film of poly[（4,4＇-bis（2-ethylhexyl）dithieno[3,2-b：2＇,3＇-d]silole）-2,6-diyl-alt-（4,7-bis （2-thienyl）-2,1,3-benzothiadiazole）-5,5＇-diyl] （SiPCPDTBT） and the composite thin film of SiPCPDTBT：POSS-C60 indicated efficient electron transfer from SiPCPDTBT to POSS-C60 with inhibited back-transfer. BHJ PSCs made by SiPCPDTBT mixed with POSS-C60 yielded the power conversion efficiencies （PCEs） of 1.50%. Under the same operational conditions, PCEs observed from BHJ PSCs made by SiPCPDTBT mixed with [6,6]-phenyl-C61-butyric acid methyl ester were 0.92%. These results demonstrated that POSS-C60 is a potentially good electron acceptor for inverted BHJ PSCs.