Title :
The relationship between molecular structure and field effect mobility in organic semiconductors
Author_Institution :
Dept. of Chem. & Fac. of Eng., Univ. of Georgia, Athens, GA
Abstract :
Short conjugated phenylene-thiophene oligomers with varying alpha and omega alkyl and alkoxy substitutions were synthesized to investigate the correlation between end-group structure and electronic properties on P2TP and P3TP conjugated cores. Several oligomers had high solubility and field-effect mobility, with 5,5´-Bis(4-n-octylphenyl)-2,2´ -bithiophene showing the highest mobility (mu = 0.18 cm2/Vmiddots) and on/off ratio of 107. Thin film morphologies analyzed using atomic force microscopy revealed higher nucleation densities for branched alkoxy side chain molecules compared to their straight alkyl side chain counterparts. Field effect mobility showed an inverse correlation to side-chain bulkiness, indicating a strong morphological component to charge transport. Novel methods of solution processing involving alignment under shear and the demonstration of these materials in low voltage aqueous sensors are highlighted.
Keywords :
atomic force microscopy; conducting polymers; molecular electronics; nucleation; organic field effect transistors; organic semiconductors; semiconductor thin films; 5,5´-Bis(4-n-octylphenyl)-2,2´ -bithiophene; P2TP conjugated cores; P3TP conjugated cores; alkoxy substitutions; alpha alkyl; atomic force microscopy; branched alkoxy side chain molecules; charge transport; electronic property; end-group structure; field effect mobility; molecular structure; nucleation density; omega alkyl; organic semiconductors; short conjugated phenylene-thiophene oligomers; side-chain bulkiness; solubility; thin film morphology; voltage aqueous sensors; Atomic force microscopy; Dielectric thin films; Microstructure; Morphology; OFETs; Organic semiconductors; Semiconductor materials; Semiconductor thin films; Spine; Substrates;
Conference_Titel :
Electrical Insulating Materials, 2008. (ISEIM 2008). International Symposium on
Conference_Location :
Mie
Print_ISBN :
978-4-88686-005-7
Electronic_ISBN :
978-4-88686-006-4
DOI :
10.1109/ISEIM.2008.4664452
