Bis(alkyl-thiophene) thienothiophene as hole-transport organic semiconductor

π-conjugated low-molecules having the chemical structure of bis(alkyl-thiophene)thienothiophene, abbreviated as, C6-BTTT and C12-BTTT were synthesized and evaluated in their thermal, optical and electronic characteristics. Compounds were synthesized according with Suzuki reaction or Stille reaction. Thermal analysis represents both of C6- and C12-BTTTs did not possess liquid-crystalline phase. Comparison of hole transport characteristics shows a relative high hole transport in C6-BTTT and high air-stability in C12-BTTT, representing a contribution of alkyl-substituent.