- A method for measuring the (dis)charging dynamics of organic semiconductors with
single-electron resolution in multiple environments is developed using optical
tweezers. A 1μm silica bead was coated with either a pristine organic semiconductor
or an electron donor-acceptor blend, trapped using optical tweezers, and driven with
an oscillating electrical driving force. The charge of the bead was measured
simultaneously with the photoluminescence of the organic semiconductor coating.
Uncoated silica spheres in water showed surface charges at least an order of
magnitude greater than uncoated spheres in nonpolar toluene. Coated spheres
showed charges smaller than uncoated spheres in both cases. The minimal
interaction of the semiconductor coatings with the environment provides support for
the use of optical tweezers in measuring the charge and change of charge of
microscopic particles with resolution as good as a single electron, depending on the
environment of the particle.
Keywords: Organic, Semiconductor, Optical, Tweezers, Charge, Transfer