π-Extented Conjugated Polymers Entailing Pechmann Dye Moieties for Solution-Processed Ambipolar Organic Semiconductors

In this paper,we report the design,synthesis and semiconducting behavior of two conjugated D-A polymers BPDDTE and BPDBDTE which entail BPD,a Pechmann dye framework,as electron accepting moieties and(E)-1,2-di(thiophen-2-yl)ethane with and without alkyl chains as electron donating moieties.They both show very narrow bandgaps below 1.3 eV.Based on the characterization of the field-effect transistors,thin film of BPDDT exhibits ambipolar semiconducting properties with hole and electron mobilities reaching 0.245 and 0.095 cm^(2)•V^(−1)•s^(−1),respectively,after thermal annealing.Similarly,BPDBDTE with more alkylchains shows ambipolar semiconducting behavior with hole mobility and electron mobilities reaching 0.109 and 0.081 cm^(2)•V^(−1)•s^(−1).Furthermore,BPDBDTE shows good solubilities in several common organic solvents and thus is easily solution-processible.Thus,BPDBDTE is potentially processible with inkjet printing and roll-to-roll printing techniques.