Aggregation-Induced Emission in a Polymeric Photovoltaic Donor Material

摘要

In this work, we report the aggregation-induced emission in a polymeric donor material poly(bis(2-butyloctyl)[ 2,2':5',2.-terthiophene]-4,4.-dicarboxylate-5,5'-diyl-vinylene) (PTVT-T), which exhibits a high device performance for the application of photovoltaics. Time-dependent density functional theory calculations and steady-state and time-resolved spectroscopy have been employed to reveal the underlying emission mechanism. We find that the aggregation of the PTVT-T polymer chain in solution increases the exciton luminescence lifetime and exciton emission quantum yield, which is related to the effective torsional inhibition of carbon-carbon single bonds. Compared with the aggregates in solution, the exciton emission quantum yield of the aggregates in PTVT-T film is reduced. It is attributable to exciton delocalization caused by the improvement of molecular planarity in film. We also observe that the as-cast film and thermally annealed film show distinctly different emission behaviors. This work can shed light on designing optoelectronic polymer materials with the integration of photovoltaic and light-emitting functions.

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