Non-conjugated terpolymer acceptors for highly efficient and stable lager-area all-polymer solar cells

Abstract

All-polymer solar cells (all-PSCs) have made significant progress recently, but few studies have been conducted to investigate the lab-to-manufacturing translation from the spin-coating method to the printing process. Here, the random copolymerization method and non-conjugated backbone approach are integrated to manipulate the morphology and photoelectric properties of the active layer for large-area printed all-PSCs. A series of non-conjugated terpolymer acceptors PYSe-TC6T(x) (x = 5, 10, and 20, refers to the molar ratio of TC6T unit) are developed by covalently introducing non-conjugated unit TC6T into the PYSe host bipolymer by random copolymerization. The spin-coated PYSe-TC6T(10)-based all-PSC demonstrates the best power conversion efficiency (PCE) of 13.54%, superior to the PYSe-based one (12.45%). More intriguingly, morphological studies reveal that a combination of the random polymerization and non-conjugated backbone strategy can effectively prevent the active layer from over-aggregation and improve the film quality during the printing process, thereby minimizing the efficiency and technology gap between spin-coated small-area devices and blade-coated large-area devices. By directly using the same preparation condition of spin-coating, the blade-coated small-area (0.04 cm2) delivers a PCE of 12.83% and the large-area (1.21 cm2) device achieves a PCE of 11.96% with a small PCE loss. Both PCE value and PCE loss are one of the most outstanding performances of the blade-coated all-PSCs. These findings reveal that a combination of the non-conjugated flexible backbone with random copolymerization to develop non-conjugated terpolymers is an attractive design concept to smoothly realize the lab-to-manufacturing translation.