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Control of Solid‐State Dye‐Sensitized Solar Cell Performance by Block‐Copolymer‐Directed TiO 2 Synthesis
Author(s) -
Docampo Pablo,
Guldin Stefan,
Stefik Morgan,
Tiwana Priti,
Orilall M. Christopher,
Hüttner Sven,
Sai Hiroaki,
Wiesner Ulrich,
Steiner Ulrich,
Snaith Henry J.
Publication year - 2010
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200902089
Subject(s) - materials science , band gap , photocurrent , dye sensitized solar cell , copolymer , crystallization , mesoporous material , chemical engineering , solar cell , organic solar cell , optoelectronics , nanotechnology , polymer , chemical physics , electrode , electrolyte , chemistry , organic chemistry , catalysis , engineering , composite material , physics
Hybrid dye‐sensitized solar cells are typically composed of mesoporous titania (TiO 2 ), light‐harvesting dyes, and organic molecular hole‐transporters. Correctly matching the electronic properties of the materials is critical to ensure efficient device operation. In this study, TiO 2 is synthesized in a well‐defined morphological confinement that arises from the self‐assembly of a diblock copolymer—poly(isoprene‐ b ‐ethylene oxide) (PI‐ b ‐PEO). The crystallization environment, tuned by the inorganic (TiO 2 mass) to organic (polymer) ratio, is shown to be a decisive factor in determining the distribution of sub‐bandgap electronic states and the associated electronic function in solid‐state dye‐sensitized solar cells. Interestingly, the tuning of the sub‐bandgap states does not appear to strongly influence the charge transport and recombination in the devices. However, increasing the depth and breadth of the density of sub‐bandgap states correlates well with an increase in photocurrent generation, suggesting that a high density of these sub‐bandgap states is critical for efficient photo‐induced electron transfer and charge separation.