title: High performance p-type molecular electron donors for OPV applications via alkylthiophene catenation chromophore extension.
abstract: The synthesis of key 4-alkyl-substituted 5-(trimethylsilyl)thiophene-2-boronic acid pinacol esters3allowed a simplified alkylthiophene catenation process to access bis-, ter-, quater-, and quinquethiophene π-bridges for the synthesis of acceptor-π-bridge-donor- π-bridge-acceptor (A-π-D-π-A) electron donor molecules. Based on the known benzodithiophene-terthiophene-rhodanine (BTR) material, theBXRseries of materials,BMR(X = M, monothiophene),BBR(X = B, bithiophene), knownBTR(X = T, terthiophene),BQR(X = Q, quaterthiophene), andBPR(X = P(penta), quinquethiophene) were synthesised to examine the influence of chromophore extension on the device performance and stability for OPV applications. TheBTxR(x = 4, butyl, and x = 8, octyl) series of materials were synthesised by varying the oligothiophene π-bridge alkyl substituent to examine structure-property relationships in OPV device performance. The devices assembled using electron donors with an extended chromophore (BQRandBPR) are shown to be more thermally stable than theBTRcontaining devices, with un-optimized efficiencies up to 9.0% PCE.BQRhas been incorporated as a secondary donor in ternary blend devices withPTB7-Thresulting in high-performance OPV devices with up to 10.7% PCE.
authors.affiliation: School of Chemistry, Bio21 Institute, University of Melbourne, Parkville Vic 3010, Melbourne, Australia.
authors.forename: Paul B
authors.initials: PB
authors.lastname: Geraghty
authors.affiliation: School of Chemistry, Bio21 Institute, University of Melbourne, Parkville Vic 3010, Melbourne, Australia.
authors.forename: Calvin
authors.initials: C
authors.lastname: Lee
authors.affiliation: School of Chemistry, Bio21 Institute, University of Melbourne, Parkville Vic 3010, Melbourne, Australia.
authors.forename: Jegadesan
authors.initials: J
authors.lastname: Subbiah
authors.affiliation: School of Chemistry, Bio21 Institute, University of Melbourne, Parkville Vic 3010, Melbourne, Australia.
authors.forename: Wallace W H
authors.initials: WW
authors.lastname: Wong
authors.affiliation: School of Chemistry, Bio21 Institute, University of Melbourne, Parkville Vic 3010, Melbourne, Australia.
authors.forename: James L
authors.initials: JL
authors.lastname: Banal
authors.affiliation: School of Chemistry, University of Melbourne, Parkville Vic 3010, Melbourne, Australia.
authors.forename: Mohammed A
authors.initials: MA
authors.lastname: Jameel
authors.affiliation: School of Chemistry, University of Melbourne, Parkville Vic 3010, Melbourne, Australia.
authors.forename: Trevor A
authors.initials: TA
authors.lastname: Smith
authors.affiliation: School of Chemistry, Bio21 Institute, University of Melbourne, Parkville Vic 3010, Melbourne, Australia.
authors.forename: David J
authors.initials: DJ
authors.lastname: Jones
keywords: molecular materials; nematic liquid crystal; organic solar cells; organic synthesis; p-type organic semiconductors; small molecule