title: Poly(sulfobetaine methacrylate)s as electrode modifiers for inverted organic electronics.
abstract: We demonstrate the use of poly(sulfobetaine methacrylate) (PSBMA), and its pyrene-containing copolymer, as solution-processable work function reducers for inverted organic electronic devices. A notable feature of PSBMA is its orthogonal solubility relative to solvents typically employed in the processing of organic semiconductors. A strong permanent dipole moment on the sulfobetaine moiety was calculated by density functional theory. PSBMA interlayers reduced the work function of metals, graphene, and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) by over 1 eV, and an ultrathin interlayer of PSBMA reduced the electron injection barrier between indium tin oxide (ITO) and C70 by 0.67 eV. As a result, the performance of organic photovoltaic devices with PSBMA interlayers is significantly improved, and enhanced electron injection is demonstrated in electron-only devices with ITO, PEDOT:PSS, and graphene electrodes. This work makes available a new class of dipole-rich, counterion-free, pH insensitive polymer interlayers with demonstrated effectiveness in inverted devices.
authors.affiliation: Department of Polymer Science and Engineering, University of Massachusetts , 120 Governors Drive, Amherst, Massachusetts 01003, United States.
authors.forename: Hyunbok
authors.initials: H
authors.lastname: Lee
authors.forename: Egle
authors.initials: E
authors.lastname: Puodziukynaite
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhang
authors.forename: John C
authors.initials: JC
authors.lastname: Stephenson
authors.forename: Lee J
authors.initials: LJ
authors.lastname: Richter
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Fischer
authors.forename: Dean M
authors.initials: DM
authors.lastname: DeLongchamp
authors.forename: Todd
authors.initials: T
authors.lastname: Emrick
authors.forename: Alejandro L
authors.initials: AL
authors.lastname: Briseno