Nature-Inspired Polymers: Promising Materials for OTFT-Based Sensors
MetadataShow full item record
The concept of an organic thin film transistor was first introduced in the late 1980s and research was directed toward two key merits of performance, field-effect mobility and current ON/OFF ratio. Today these two key merits of performance are still highly sought after; however, a shortcoming associated with most organic semiconductors is their susceptibility to chemical interactions and photo-excitation; to name but a few of their caveats. Consequently, the development of organic semiconductors with high charge carrier transport as well as good air stability is still desired. Nature provides a vast diversity of materials and looking for natural or nature inspired semiconductors appears to be a promising route towards interesting and pertinent materials. Organic thin film transistors based on natural or natural-inspired semiconductors such as indigo, -carotene, indanthrene, and perylene diimide have demonstrated good charge carrier transport and some cases demonstrated equally good stability in ambient conditions. In this work, a number of moderately to excellent air stable polymeric semiconductors were designed and synthesized that were nature inspired. Chapter 3 describes the synthetic account and elaborates on a broad spectrum of properties pertaining to the novel fluorene-fused triphenodioxazine based polymer (PFTPDOBT). PFTPDOBT exhibited excellent charge transport performance in ambient conditions reaching hole mobilities as high as ~10^-2 cm^2 V^-1 s^-1 and modest hole mobilities in water-gated transistors (~10^-3 cm^2 V^-1 s^-1). In Chapter 4, a series of pyrazino[2,3-g]quinoxaline-2,7-dione (PQx) based polymers were developed and characterized. These PQx based polymers displayed exciting UV-Vis-NIR spectra when in the presence of an organic acid or Lewis acid. Their electrical characteristics in OTFTs were typical of ambipolar charge transport. Hole mobilities reached as high as ~10^-2 cm^2 V^-1 s^-1 with corresponding electron mobilities as high as ~10^-3 cm^2 V^-1 s^-1. Lastly, Chapter 5 gives accounts on significant research pertaining to novel polymeric semiconductors based on the pyrimido[4,5-g]quinazoline-4,9-dione (PQ) moiety. A systematic study of PQ-based polymeric semiconductors is presented in both nitrogen, ambient, and aqueous environments. Typical hole charge transport was obtained between ~10^-2 and ~10^-3 cm^2 V^-1 s^-1. Both PPQ2T-BT-24 and PPQ2T-TT-24 demonstrated moderate to excellent stability in these environments. To exploit the photo-excitation of organic semiconductors, a series of PQ-based polymeric semiconductors were incorporated in phototransistors and also blended with PC61BM. The PPQ2T-BT-24:PC61BM blend reached ultrafast response times as low as 1 ms for rise and 8 ms for fall with photoresponsivity as high as 0.88% and EQE of 189%. Lastly, PPQ2T-BT-24 and PPQ2T-TT-24 were incorporated into OTFT gas sensors where they demonstrated low detection limits with fast recovery times for a particular analyte.
Cite this version of the work
Jesse Quinn (2017). Nature-Inspired Polymers: Promising Materials for OTFT-Based Sensors. UWSpace. http://hdl.handle.net/10012/11844