Trialkylsilyl ethynyl functionalized tetraceno[2,3- b]thiophene and anthra[2,3-b]thiophene organic transistors

A series of ethynyl-substituted molecules with the tetraceno[2,3- b]thiophene and anthra[2,3-b]thiophene core have been synthesized. The aim was to investigate the impact of differently bulky side-chain substituents on the packing of the molecule in thin film, and hence its thin film transistor (TFT) mobility. Three R-groups were used, namely the triisopropyl-, triethyl- and trimethyl- silylethynyl groups. We did not observe a direct correlation between substituent size and TFT mobility. However, the 5,12-bis(triisopropylsilylethynyl)tetraceno[2,3-b]thiophene has a mobility as high as 1.25cm2/Vs, the 5,12-bis(trimethylsilylethynyl)tetraceno[2,3-b]thiophene has a mobility about 0.00616cm2/Vs,while 5,10-bis(triethylsilylethynyl)anthra[2,3-b]thiophene and 5,10-bis (trimethylsilylethynyl)anthra[2,3- b]thiophene has a mobility of 10-4cm2/Vs on phenylsilane and octadecyltrichloros ilane-treated surfaces respectively.