title: Solution Processed Titanyl Phthalocyanines as Donors in Solar Cells: Photoresponse to 1000 nm.
abstract: We report a route to thin-film polymorphs of soluble TiOPc derivatives that exhibit similar near-IR absorptivities as vapor deposited thin-films of the parent TiOPc chromophore (phase-I and phase-II polymorphs) and demonstrate that solution-processed planar and bulk heterojunction solar cells fabricated with one of these derivatives exhibited photoactivity throughout the same near-IR wavelength range without compromising VOC. Solution-processed thin-films of soluble octakis(alkylthio)-substituted TiOPc derivatives 1-3 exhibit absorption extending to 1000 nm. When incorporated into OPV devices, the contributions from the lowest CT excitonic state (QB band) of 1 to device performance were evident in both PHJ and BHJ architectures, indicating sufficient driving force for PIET. This contribution was improved via intimate mixing of donor and acceptor molecules in a BHJ architecture, albeit with a decrease in efficiency. IPCE of the best performing BHJ device revealed a contribution from 1 exceeding that of acceptor PCBM, and extending to 1000 nm.
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721-0041, United States.
authors.forename: Mayank
authors.initials: M
authors.lastname: Mayukh
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721-0041, United States.
authors.forename: Mariola R
authors.initials: MR
authors.lastname: Macech
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721-0041, United States.
authors.forename: Diogenes
authors.initials: D
authors.lastname: Placencia
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721-0041, United States.
authors.forename: Yu
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721-0041, United States.
authors.forename: Neal R
authors.initials: NR
authors.lastname: Armstrong
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721-0041, United States.
authors.forename: Dominic V
authors.initials: DV
authors.lastname: McGrath
keywords: X-ray diffraction; near-infrared; organic photovoltaic; organic thin films; polymorphs