Synthesis and Solar Cell Application of New Alternating Donor-Acceptor Copolymers Based on Variable Units of Fluorene, Thiophene, and Phenylene

A new series of donor acceptor copolymers were synthesized via the Witting route and applied as an active layer in organic thin-films solar cells. These copolymers are composed of fluorene thiophene and phenylene thiophene units. The ratio between those was systematically varied, and copolymers containing 0%, 50%, and 75% of phenylene thiophene were characterized and evaluated when used in photovoltaic devices. The copolymers' composition, photophysical, electrical, and morphological properties are addressed and correlated with device performance. The 50% copolymer ratio was found to be the best copolymer of the series, yielding a power conversion efficiency (PCE) under air mass (AM) 1.5 conditions of 2.4% in the bilayer heterojunction with the C-60 molecule. Aiming at flexible electronics applications, solutions based on the heterojunction of this copolymer with PCBM (6,6-phenyl-C-61-butyric acid methyl ester) were also successfully deposited using an inkjet printing method and used as an active layer in solar cells.CAPESCAPESCNPqCNPqPalo Alto Research Center (PARC)Palo Alto Research Center (PARC)INEOINE

Synthesis and Solar Cell Application of New Alternating Donor–Acceptor Copolymers Based on Variable Units of Fluorene, Thiophene, and Phenylene

A new series of donor–acceptor copolymers were synthesized via the Witting route and applied as an active layer in organic thin-films solar cells. These copolymers are composed of fluorene–thiophene and phenylene–thiophene units. The ratio between those was systematically varied, and copolymers containing 0%, 50%, and 75% of phenylene–thiophene were characterized and evaluated when used in photovoltaic devices. The copolymers' composition, photophysical, electrical, and morphological properties are addressed and correlated with device performance. The 50% copolymer ratio was found to be the best copolymer of the series, yielding a power conversion efficiency (PCE) under air mass (AM) 1.5 conditions of 2.4% in the bilayer heterojunction with the C₆₀ molecule. Aiming at flexible electronics applications, solutions based on the heterojunction of this copolymer with PCBM (6,6-phenyl-C₆₁-butyric acid methyl ester) were also successfully deposited using an inkjet printing method and used as an active layer in solar cells