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Why Inverted Small Molecule Solar Cells Outperform Their Noninverted Counterparts
Author(s) -
Nanova Diana,
Scherer Michael,
Schell Felix,
Zimmermann Johannes,
Glaser Tobias,
Kast Anne Katrin,
Krekeler Christian,
Pucci Annemarie,
Kowalsky Wolfgang,
Schröder Rasmus R.,
Lovrinčić Robert
Publication year - 2015
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.201502943
Subject(s) - materials science , organic solar cell , fullerene , substrate (aquarium) , molecule , energy conversion efficiency , deposition (geology) , small molecule , heterojunction , polymer solar cell , chemical physics , charge (physics) , solar cell , nanotechnology , optoelectronics , organic chemistry , composite material , polymer , chemistry , paleontology , biochemistry , oceanography , physics , quantum mechanics , sediment , biology , geology
It is shown that the effect of substrate heating on the photo conversion efficiency in vacuum‐deposited small molecule organic solar cells is closely related to the improved free charge generation in ordered C 60 regions. The formation of these ordered regions strongly depends on the deposition sequence in the device and differs therefore between inverted and noninverted cells. Substrate‐induced local fullerene ordering is found in small molecule:C 60 bulk heterojunctions (BHJs) deposited on pristine C 60 at elevated temperatures. This does not occur for BHJs deposited under identical conditions on pristine donor molecule layers, despite similar degrees of phase separation in both cases. These findings point to a hitherto unidentified advantage of inverted over noninverted solar cells that manifests itself in a higher charge separation efficiency.