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

• DOI: 10.1021/acsami.6b16487
• Publication Date: 2017-03-30T22:42:21Z
• Authors: Yun Long; Gordon J. Hedley; Arvydas Ruseckas; Mithun Chowdhury; Thomas Roland; Luis A Serrano; Graeme Cooke; Ifor D. W. Samuel
• Keywords: Acceptor; Biexciton; Annihilation

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 planar heterojunctions with an acceptor, exciton-exciton annihilation, and depolarization. The average diffusivity increases upon annealing from 1.6 × 10-3 to 3.6 cm2 s-1, resulting enhancement of mean two-dimensional length (LD = (4Dτ)1/2) 15 27 nm. About 30% excitons get trapped very quickly as-cast films. high coefficient leads it being able harvest efficiently large domains bulk heterojunctions.