Ternary Blend Strategy Using Structural Isomeric Donor Polymers for Improving the Performance of PC<SUB>61</SUB>BM-based Indoor Photovoltaics

다국어 초록 (Multilingual Abstract)

In this report, two isomeric BDT-based copolymers, TTE25 and TTE36, were designed and synthesized. The difference in the linking positions of carboxylates in the thienothiophene unit of TTE25 and TTE36 leads to significant different properties between these two copolymers, including the HOMO level, absorption region and crystallinity. Owing to the good miscibility, and especially, of the broad complementary absorption of the TTE25 and TTE36 blend, mixtures of these two polymers at different composition were applied as the donor for the active layer in PC61BM-based organic indoor photovoltaics (IPVs). Under 1000 lux white LED illumination, the optimized TTE36:TTE25:PC61BM (0.8:0.2:1.0 wt. ratio)-ternary-blend-based IPVs achieved a significant increase of PCE to 11.14% compared to the moderate PCE of 6.72% for those without TTE25. This study demonstrated that blending two isomeric polymers is a promising strategy for realizing high-efficiency IPV devices under indoor light conditions.