Charge transfer nano-cocrystals for organic electronics
We have been using reprecipitation to create nanocrystalline wires of various charge transfer co-crystals, in particular
phenothiazine:tetracyanoquinodimethane
(PTZ:TCNQ). Recent theoretical calculations have shown that it could be
have a useful organic semiconductor. Organic semiconductors are being heavily investigated for
applications in electronics,
where they could replace Silicon as the active material in transistors and related devices. While their electronic properties
may not match
those of Silicon, they have other advantages such as flexibility, low cost, and ease of processing. In addition,
many organic semiconductors possess good mobilities for
both holes and electrons, making them ambipolar, compared to
doped Silicon, which is bipolar. New types of devices have been proposed using ambipolar semiconductors,
for example for
use radio frequency inverters. In addition, the ambipolar nature may make them useful as charge transport additives in
organic photovoltaic devices.
SEM images of wires that were freeze-dried following nanoprecipitation show nanowires with
diameters ranging from ~100 nm to several microns, and lengths from ten to
several hundred microns. We have been
characterizing the optical and electronic properties of these materials in collaboration with Prof. Patrick Vora at
George
Mason University and Prof. Pratibha Dev at Howard University.
With support from the Georgetown Environmental Initiative, we are constructing a characterization station with a solar
simulator for device efficiency measurements and
a wavelength tunable raster system for measuring spatial and wavelength
dependence response. |
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