Thieno[3,2-b]thiophene flanked para-azaquinodimethane π-extended aromatic-quinoidal polymers

A series of thieno[3,2- b ]thiophene (TT) flanked para -azaquinodimethane ( p -AQM) based quinoidal conjugated polymers PAQM2TT-T , PAQM2TT-BT and PAQM3TT were designed in a strategy to extend the aromatic-quinoidal π-system. The three polymers were synthesized by Stille polycondensation , and their opto-electronic properties and device performance in field-effect transistors have been explored. From absorption spectroscopy , the polymers show low bandgaps (1.54–1.57 eV) and high HOMO energy levels. They exhibit typical p-type behavior according to the results of the characterization of the field-effect transistors with average charge carrier mobilities of 0.08 cm 2 V −1 s −1 for PAQM2TT-T , 0.12 cm 2 V −1 s −1 for PAQM2TT-BT and 0.05 cm 2 V −1 s −1 for PAM3TT . This report presents an alternative π-extended quinoidal-donor strategy to control the molecular design and properties of new p -AQM-based conjugated polymers . • A novel monomer unit containing thienothiophene and p-azaquinodimethane moieties has been designed and synthesized. • Pi-extented aromatic-quinoidal systems have been prepared. • Bottom-gate top-contact field-effect transistors show mobilities up to 0.12 cm 2 V −1 s −1.