Premium
Electron–Hole Recombination in Uniaxially Aligned Semiconducting Polymers
Author(s) -
Zaumseil Jana,
Groves Chris,
Winfield Jessica M.,
Greenham Neil C.,
Sirringhaus Henning
Publication year - 2008
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.200800863
Subject(s) - recombination , materials science , polymer , electron , perpendicular , semiconductor , anisotropy , optoelectronics , diffusion , monte carlo method , chemical physics , condensed matter physics , optics , physics , thermodynamics , chemistry , composite material , geometry , biochemistry , mathematics , statistics , quantum mechanics , gene
A promising, general strategy for improving performance of optoelectronic devices based on conjugated polymer semiconductors is to make better use of the fast intrachain transport along the covalently bonded polymer backbone. Little is known, however, about how the recombination rate between electrons and holes would be affected in device structures in which current flow is primarily along the polymer chain. Here a light‐emitting field effect transistor (LFET) structure with a uniaxially aligned semiconducting polymer is used to show that the width and shape of the recombination zone depend strongly on polymer alignment. For alignment of the polymer parallel to the current the emission zone is 5–10 times wider than for perpendicular alignment. 2D drift‐diffusion modeling is used to show that such significant widening of the recombination zone in the case of parallel alignment implies that the recombination rate constant is more than 100 times lower than expected for standard Langevin recombination. On the basis of Monte Carlo modeling it is proposed that such unexpected weak recombination is a result of the significant mobility anisotropy of the aligned polymer. These results provide new fundamental insight into the recombination physics of polymer semiconductors.