Design, synthesis and characterization of thiazole-based conjugated polymers and their applications to n-channel organic electronics

Abstract

In the past several decades, π-conjugated organic and polymeric semiconducting materials have attracted significant attention due to their promising electronic and optoelectronic properties. Therefore, their potential in applications to electronic and optoelectronic devices have been investigated, including applications in organic field-effect transistors (OFETs), organic photovoltaics (OPVs), and organic light-emitting diodes (OLEDs), etc. In the past two decades, a great number of conjugated polymers with mobility surpassing that of amorphous silicon have been reported. However, most of these high-mobility conjugated polymers are either hole transport or ambipolar (electron and hole transport) semiconductors; only a few electron transport conjugated polymers with high electron mobility (µe) have been reported to date. The development of high-mobility electron transporting conjugated polymers falls behind advances in their hole transporting counterparts. However, high‐performance pure electron-transporting conjugated polymers for pure n-channel organic electronic devices are highly desirable in applications such as metal‐oxide‐semiconductor (CMOS)‐like complementary circuits, organic thermoelectrics, and all‐polymer solar cells. Among many electron-poor units, thiazoles stand out as a promising building block for high performance organic semiconductors. This dissertation discusses the development of thiazole-based π-conjugated semiconducting polymers to enhance the electron field-effect mobilities by advancing intra- and inter-molecular interactions between polymer chains, and the enhancement of ambient stability by decreasing the energy levels of frontier molecular orbitals. The structure-process-property relationships of thiazole-based n-channel conjugated polymers are studied in this thesis.