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Title: Annealing effect on donor-acceptor interface and its impact on the performance of organic photovoltaic devices based on PSiF-DBT copolymer and C{sub 60}

In this work, poly[2,7-(9,9-bis(2-ethylhexyl)-dibenzosilole)-alt-4,7-bis(thiophen-2-yl) benzo-2,1,3-thiadiazole] (PSiF-DBT) was used as active layer in bilayer solar cell with C{sub 60} as electron acceptor. As cast devices already show reasonable power conversion efficiency (PCE) that increases to 4% upon annealing at 100 °C. Space charge limited measurements of the hole mobility (μ) in PSiF-DBT give μ ∼ 1.0 × 10{sup −4} cm{sup 2}/(V s) which does not depend on the temperature of the annealing treatment. Moreover, positron annihilation spectroscopy experiments revealed that PSiF-DBT films are well stacked even without the thermal treatment. The variations in the transport of holes upon annealing are then small. As a consequence, the PCE rise was mainly induced by the increase of the polymer surface roughness that leads to a more effective interface for exciton dissociation at the PSiF-DBT/fullerene heterojunction.
Authors:
; ; ;  [1] ; ;  [2] ; ;  [3] ;  [4]
  1. Department of Physics, Federal University of Paraná, P.O. Box 19044, 81531-990 Curitiba, Paraná (Brazil)
  2. Department of Chemistry, Federal University of Paraná, P.O. Box 19081, 81531-990 Curitiba, Paraná (Brazil)
  3. Department of Applied Physics, Aalto University School of Science, P.O. Box 14100, FI-00076 Aalto (Finland)
  4. Department of Physics, Technological Federal University of Paraná, Curitiba 80230-901 (Brazil)
Publication Date:
OSTI Identifier:
22398834
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 13; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANNEALING; ANNIHILATION; BINDING ENERGY; COPOLYMERS; ELECTRONS; FILMS; FULLERENES; HETEROJUNCTIONS; HOLE MOBILITY; HOLES; INTERFACES; LAYERS; PHOTOVOLTAIC EFFECT; POSITRONS; ROUGHNESS; SOLAR CELLS; SPACE CHARGE; VALENCE