Effect of Annealing on Exciton Diffusion in a High Performance Small Molecule Organic Photovoltaic Material.

ACS Appl Mater Interfaces

Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, United Kingdom.

Published: May 2017


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Article Abstract

Singlet exciton diffusion was studied in the efficient organic photovoltaic electron donor material DTS(FBTTh). Three complementary time-resolved fluorescence measurements were performed: quenching in planar heterojunctions with an electron acceptor, exciton-exciton annihilation, and fluorescence depolarization. The average exciton diffusivity increases upon annealing from 1.6 × 10 to 3.6 × 10 cm s, resulting in an enhancement of the mean two-dimensional exciton diffusion length (L = (4Dτ)) from 15 to 27 nm. About 30% of the excitons get trapped very quickly in as-cast films. The high exciton diffusion coefficient of the material leads to it being able to harvest excitons efficiently from large donor domains in bulk heterojunctions.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5423077PMC
http://dx.doi.org/10.1021/acsami.6b16487DOI Listing

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