The synthesis and full characterisation of a novel indole-substituted nickel dithiolene [Ni(mi-5edt)2] (3) is reported, and compared to its alkyl-substituted analogue [Ni(mi-5hdt)2] (4) that has been previously communicated [Dalgleish et al., Chem. Commun., 2009, 5826] [mi-5edt = 1-(N-methylindol-5-yl)-ethene-1,2-dithiolate; mi-5hdt = 1-(N-methylindol-5-yl)- hex-1-ene-1,2-dithiolate)]. Both complexes are shown to undergo oxidative electropolymerisation, yielding polymer films that retain the redox and optical properties of the monomer. The more soluble analogue 4 is shown to form high quality thin films by spin coating, which have been utilised to fabricate field-effect transistors (FETs) and bulk heterojunction photovoltaic devices (BHJ-PVs). From FET studies, the material shows ambipolar charge transport behaviour, with a maximum carrier mobility of ∼10-6 cm 2 V-1 s-1 for electrons. By using 4 simultaneously as the electron acceptor as well as a NIR sensitiser in BHJ-PVs, the complex is shown to contribute to the photocurrent, extending light harvesting into the NIR region.
ASJC Scopus subject areas
- Materials Chemistry