Benzo[1,2-b:4,5-b′]dithiophene-based copolymers applied in bottom-contact field-effect transistors

Synthesis, Characterization and Field‐Effect Transistor Performance of Poly[2,6‐bis(3‐alkylthiophen‐2‐yl)benzo[1,2‐b;4,5‐b′]diselenophene]s

“…Also the optical band gap decreases in the same fashion, amounting to 2.04 and 1.96 eV for the CB fractions of 1a and 1b , respectively. The band gap of 1.96 is 0.05 eV smaller than the smallest band gap that was found for analogous BDT‐based copolymers 23. Despite a small difference in molecular weights between the polymers under comparison, this decrease in band gap is likely attributable to the presence of selenium atoms in 1b .…”

“…Photophysical data are summarized in Table S1 (Supporting Information). Contrary to its BDT‐analogue, 1a does not show an excimeric emission in thin film 23…”

“…The 2,2′‐dibromo‐3,3′‐bis(alkyl)‐5,5′‐bithiophene monomers 2a (dodecyl) and 2b (tetradecyl) were synthesized as reported before 23, 25. 2,6‐bis(tributylstannyl)benzo[1,2‐b:4,5‐b′]diselenophene 4 was also prepared in a similar manner to its BDT analogue 23.…”

“…The 2,2′‐dibromo‐3,3′‐bis(alkyl)‐5,5′‐bithiophene monomers 2a (dodecyl) and 2b (tetradecyl) were synthesized as reported before 23, 25. 2,6‐bis(tributylstannyl)benzo[1,2‐b:4,5‐b′]diselenophene 4 was also prepared in a similar manner to its BDT analogue 23. BDS 3 , synthesized according to literature procedures,9 was directly lithiated at the α,ω positions, and subsequently functionalized by adding tributylstannylchloride (Scheme ) in good yield.…”

“…Recently, we reported the characterization and OFET performance of poly[2,6‐bis(3‐alkylthiophen‐2‐yl)benzo[1,2‐b;4,5‐b′]dithiophene]s 23. The improved OFET performance of selenium‐containing analogues of existing polymers prompted us to incorporate BDS in this polymeric structure.…”