title: Massive enhancement of photoluminescence through nanofilm dewetting.
abstract: Due to the rather low efficiencies of conjugated polymers in solid films, their successful applications are scarce. However, recently several experiments indicated that a proper control of molecular conformations and stresses acting on the polymers may provide constructive ways to boost efficiency. Here, we report an amazingly large enhancement of photoluminescence as a consequence of strong shear forces acting on the polymer chains during nanofilm dewetting. Such sheared chains exhibited an emission probability many times higher than the nonsheared chains within a nondewetted film. This increase in emission probability was accompanied by the emergence of an additional blue-shifted emission peak, suggesting reductions in conjugation length induced by the dewetting-driven mass redistribution. Intriguingly, exciton quenching on narrow-band-gap substrates was also reduced, indicating suppression of vibronic interactions of excitons. Dewetting and related shearing processes resulting in enhanced photoluminescence efficiency are compatible with existing fabrication methods of polymer-based diodes and solar cells.
authors.affiliation: Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan.
authors.forename: Peiwei
authors.initials: P
authors.lastname: Lee
authors.forename: Wei-Cheng
authors.initials: WC
authors.lastname: Li
authors.forename: Bin-Jih
authors.initials: BJ
authors.lastname: Chen
authors.forename: Chih-Wei
authors.initials: CW
authors.lastname: Yang
authors.forename: Chun-Chih
authors.initials: CC
authors.lastname: Chang
authors.forename: Ioan
authors.initials: I
authors.lastname: Botiz
authors.forename: Günter
authors.initials: G
authors.lastname: Reiter
authors.forename: Tsang-Lang
authors.initials: TL
authors.lastname: Lin
authors.forename: Jau
authors.initials: J
authors.lastname: Tang
authors.forename: Arnold Chang-Mou
authors.initials: AC
authors.lastname: Yang