Synthesis and characterisation of novel organic semiconductors

Organic semiconductors (OSCs) attract considerable attention from blue-chip companies and research communities as potential substitutes of inorganic counterparts in electronic devices. Thiophenes are one of the most extensively studied and highly topical classes of electron-rich OSCs. Linked compounds are known for their photoluminescent and conducting properties. On the other hand, fused thiophenes (FTs), both as small molecules and conducting polymers containing these blocks, demonstrate a different approach to broaden and improve the properties of this family of materials. FTs are highly ordered structures, with good potential for high charge-mobilities. Simultaneously, they are more environmentally resistant than many other OSCs, due to their wider HOMO-LUMO gaps. The review regarding these interesting materials and recent literature examples are presented in Chapter 1. During the course of my PhD research work several novel diindenodithioenothiophene (DITT) based molecular and polymeric materials were prepared and investigated. The parent compound (77), obtained through a multistep synthesis, comprises a central dithienothiophene-core and symmetrically attached indene-moieties at both sides. It was found to be sparingly soluble and in order to enable further synthetic manipulations was successfully derivatised with solubilising groups (78). Further oxidation of the thienyl sulfur to the corresponding sulfone afforded a highly photoluminescent compound (79). These three materials were characterised in terms of their chemical structure and properties. The findings are discussed in Chapter 2 along with the results of the performance of an OFET device, which was fabricated with 77 as the active semiconductor. Further work with the DITT-based materials involved polymerisations of 78 and 79 via a Yamamoto protocol and also copolymerisations of 78 with the fluorene and paraphenylene derivatives achieved through Suzuki polycondensations. The details of the synthetic procedures are described in Chapter 3. Chapter 4 presents the results of the property investigations of the synthesised polymers.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral-pg

Grantor dc:publisher.institution

University of Strathclyde

Year dc:date.issued

2011

Author dc:creator

• Afonina, Irina

DOI

10.48730/awtr-m197

Identifier

T12777

OAI identifier oai:identifier

oai:strathclyde:g158bh30q