| Abstract
| - A series of trialkylsilylethynyl-functionalized molecules has been made to investigate the relationship between the size of the trialkyl substituent to the length of the conjugated core. The tri-isopropyl group worked best for the tetraceno[2,3-b]thiophene core, giving a 2-D bricklayer packing in the single crystal. Single-crystal structures of the other molecules are also presented and discussed in the context of organic thin-film 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 tri-isopropyl-, triethyl-, and trimethylsilylethynyl groups. We did not observe a direct correlation between substituent size and TFT mobility. However, the 5,12-bis(tri-isopropylsilylethynyl)tetraceno[2,3-b]thiophene has a mobility as high as 1.25 cm2/V·s, the 5,12-bis(trimethylsilylethynyl)tetraceno[2,3-b]thiophene has a mobility of about 0.00616 cm2/V·s, while 5,10-bis(triethylsilylethynyl)anthra[2,3-b]thiophene and 5,10-bis(trimethylsilylethynyl)anthra[2,3-b]thiophene have a mobility of 10−4cm2/V·s on phenylsilane- and octadecyltrichlorosilane-treated surfaces respectively.
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