Alkoxy-Substituted Anthra[1,2- c:5,6- c′]bis([1,2,5]thiadiazole) (ATz): A New Electron-Acceptor Unit in the Semiconducting Polymers for Organic Electronics

A new type of thiadiazole-based acceptor unit and its donor-acceptor copolymers were synthesized and characterized to develop the high-performance semiconducting polymers for organic field-effect transistors (OFETs) and organic photovoltaics (OPVs). We successfully synthesized an anthra[1,2-c:5,6-c′]bis([1,2,5]thiadiazole) (ATz) core and ATz-quaterthiophene copolymers. These copolymers possess a wide energy gap of ca. 1.8 eV and a deeper HOMO energy levels around â?5.4 eV than that of typical thiadiazole-oligothiophene copolymers. Such weak electron-accepting nature may be due to the decreased electron affinity of the ATz core by an existence of alkoxy groups with strong electron-donating ability. The ATz copolymers exhibited good semiconducting properties with hole mobility of up to 0.03 cm² V^-1 s^-1 and photovoltaic response with PCE of up to 5.7%, despite the unfavorable molecular orders, thin-film structure, and/or amorphous structure.