Effect of Metal Coordination on Photocurrent Response Properties of a Tetrathiafulvalene Organogel Film

Organic low molecular
weight gelators with a tetrathiafulvalene (TTF) unit have received
considerable attention because the formed gels usually exhibit redox
active response and conducting or semiconducting properties. However,
to our knowledge, metal coordination systems have not been reported
for TTF-derived gels up to date. We have designed and synthesized
a series of TTF derivatives with a diamide-diamino moiety that can
coordinate to specific metal ions with square coordination geometry.
Gelation properties and morphologies of the films prepared by the
gelators in different hydrophobic solvents are characterized. The
TTF derivative with a dodecyl group shows effective gelation properties,
and electrodes with the organogel films are prepared. The effect of
the Ni­(II) and Cu­(II) coordination on the photocurrent response property
of the electrodes is examined. The metal square coordination significantly
increases the photocurrent response. This gel system is the first
metal coordination related TTF-gel-based photoelectric material. The
mechanism of the metal coordination-improved photocurrent response
property is discussed based on the crystal structural analysis and
theoretical calculations.