title: Modifying the Chemical Structure of a Porphyrin Small Molecule with Benzothiophene Groups for the Reproducible Fabrication of High Performance Solar Cells.
abstract: A porphyrin-based molecule DPPEZnP-BzTBO with bulky benzothiophene groups was designed and synthesized as an electron donor material for bulk heterojunction (BHJ) solar cells. The optimized devices under thermal annealing (TA) and then chloroform solvent vapor anneanling (SVA) for 80 s exhibited an outstanding power conversion efficiencie (PCE) of 9.08%. Contrasted with the smaller thienyl substituted analogues we reported previously, DPPEZnP-BzTBO-based BHJ solar cells exhibited a higher open circuit voltage due to the lower highest occupied molecular orbital energy level. The TA post-treatment of the active layers induced the formation of more crystallized components, and the subsequent SVA provided a driving force for the domain growth, resulting in more obvious phase segregation between the donor and the acceptor in nanoscale. Furthermore, the PCEs kept above 95% upon the further SVA treatment within the time range of 60 to 95 s probably because the bulky benzothiophene groups retard the too quick change of crystallinity, providing a wide processing window for the reproducible device fabrication.
authors.affiliation: State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology , 381 Wushan Road, Guangzhou 510640, China.
authors.forename: Tianxiang
authors.initials: T
authors.lastname: Liang
authors.affiliation: State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology , 381 Wushan Road, Guangzhou 510640, China.
authors.forename: Liangang
authors.initials: L
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology , 381 Wushan Road, Guangzhou 510640, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology , 381 Wushan Road, Guangzhou 510640, China.
authors.forename: Wenzhan
authors.initials: W
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology , 381 Wushan Road, Guangzhou 510640, China.
authors.forename: Xiaobin
authors.identifier: http://orcid.org/0000-0003-1562-3190
authors.initials: X
authors.lastname: Peng
authors.affiliation: State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology , 381 Wushan Road, Guangzhou 510640, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Cao
keywords: bulky benzothiophene groups; large open circuit voltages; organic solar cells; porphyrins; solvent vapor annealing