Photostability of benzodithiophene based polymer: effect of PC₆₀BM and intermolecular interactions

Abstract Organic solar cells working under continuous light irradiation are prone to photo-induced degradation. Photostabilities of benzodithiophene- alt -2-decyltetradecyl substituted isoindigo (PBDTI-DT) copolymer in solution, and as pristine film, a PBDTI-DT:PC 60 BM bulk hetero-junction (BHJ) film were investigated for more than 70 h simulated AM 1.5 irradiation. The photodegradation kinetics studied standalone polymer chains found be fast due the absence intermolecular interaction while inter-chain films kept backbone intact against light-induced Further addition PC made BHJ stable serves photoprotective layer radical scavenger. This conclusion was supported by similar XRD traces during degradation indicated bleaching shifted with increasing photon stress. In addition, absorption PBDTI-DT reduced 80 56%, respectively, after photo-degradation.