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

ABSTRACT: Singlet exciton diffusion was studied in the efficient organic photovoltaic electron donor material DTS(FBTTh₂)₂. 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^-3 to 3.6 × 10^-3 cm² s^-1, resulting in an enhancement of the mean two-dimensional exciton diffusion length (L_D = (4D?)^1/2) 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.

SUBMITTER: Long Y

PROVIDER: S-EPMC5423077 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature

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

Long Yun Y Hedley Gordon J GJ Ruseckas Arvydas A Chowdhury Mithun M Roland Thomas T Serrano Luis A LA Cooke Graeme G Samuel Ifor D W IDW

ACS applied materials & interfaces 20170418 17

Singlet exciton diffusion was studied in the efficient organic photovoltaic electron donor material DTS(FBTTh2)2. 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 × 10-3 to 3.6 × 10-3 cm2 s-1, resulting in an enhanc ...[more]

PMID: 28358189

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