Page 19 - Organic Electronics in Sensors and Biotechnology

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for such sensors for a vast number of analytes in areas encompassing
every aspect of life (e.g., medicine, environment, food and beverage,
chemical industry, homeland security) as well as the need, which
remains a challenge, for compact, field-deployable, inexpensive,
versatile, and user-friendly sensors and sensor arrays. The organic
electronics-based sensors––whether monitoring the effect of analytes
on the photoluminescence of, e.g., analyte-sensitive dyes, where the
excitation source is a thin OLED pixel array, or monitoring the effect of
analytes on the attributes of the OFETs––are very promising in
alleviating existing sensor-related issues such as the limited portability
and high cost and maintenance. Importantly, such sensors are not as
sensitive to the limiting issues in organic semiconductors (e.g., long-
term stability), in particular when considering inexpensive disposable
devices. Indeed, attributes such as small, potentially miniaturized size,
compatibility with microfluidic architectures, and high sensitivity have
been demonstrated in organic electronics-based sensors. The efficacy
of such sensors for simultaneous detection of multiple analytes using
small-size sensor arrays has also been shown. Such sensors build on the
ability to fabricate (micro)arrays of multiple OLED pixels and OFETs. As
an example, tens of OLED pixels, ranging in size from millimeters down
to nanometers, can be fabricated combinatorially on compact substrates.
Each pixel (or a small group of pixels) can be associated with a different
analyte. Such pixels can be of single or multiple colors. Moreover, OLED-
based sensors can be further integrated with organic-based or other thin-
film photodetectors to generate very thin, portable sensors. In OFETs,
where charge mobility is low in comparison to crystalline Si, the promise
is in their potential lower cost and design flexibility. For example, for
biomedical applications the advantage is in the possibility to fabricate
devices on large areas on unusual substrates such as paper, plastic, or
fabrics.
The use of organic semiconductors in other biotechnological
applications is drawing significant interest as well. As an example, in
cell biology where the interface between an aqueous fluid and a solid
surface is of great importance, electric biasing is a promising approach
for dynamic control of surface properties and thus for advancing
research in this field. Demonstrated solid-state ion pumps based on
conducting polymers are also promising for such studies.
This volume covers various aspects of ongoing R&D in organic
electronics for sensors and biotechnology. Chapter 1 describes scaling
effects in organic transistors and on the sensing response to organic
compounds. Chapter 2 describes sensing of inorganic compounds
using OFETs, including gold nanoparticle-modified FET sensors.
Chapter 3 describes organic semiconductor-based strain and pressure
sensors. The chapter presents the state-of-the-art technologies and
applications, including sensors on conformable, large surfaces.
Chapter 4 deals with the characterization of the electronic properties
of organic materials by impedance spectroscopy and the integration