Crystalline Cooperativity of Donor and Acceptor Segments in Double-Cable Conjugated Polymers toward Efficient Single-Component Organic Solar Cells.

Abstract

The crystalline cooperativity of the donor and acceptor segment in double-cable conjugated polymers plays an important role in the nanophase separation and photovoltaic performance in single-component organic solar cells (SCOSCs). Two double-cable conjugated polymers with the same conjugated backbone and perylene bisimide (PBI) side units were designed in which PBIs were positioned symmetrically and perpendicularly (P1) and asymmetrically and slantingly (P2) along the conjugated backbones. After thermal annealing, both conjugated backbones and PBI side units in P1 tend to form ordered nanostructures, while PBI side units in P2 dominated the crystallization and hamper the crystallization of conjugated backbones. P1 showed good crystalline cooperativity between conjugated backbones and PBI side units, resulting in improved power conversion efficiencies (PCEs) up to 3.43 % in SCOSCs, while P2 with poor crystalline cooperativity exhibited PCEs below 2.42 %.