Thieno[3,2-b]thiophene oligomers and their applications as p-type organic semiconductors

• Published in: Journal of materials chemistry 2009-01, Vol.19 (21), p.3449-3456
• Main Authors: AHMED, Moawia O, CHUNMEI WANG, KEG, Peisi, PISULA, Wojciech, LAM, Yeng-Meng, ONG, Beng S, NG, Siu-Choon, CHEN, Zhi-Kuan, MHAISALKAR, Subodh G
• Format: Article
• Language: English
• Subjects: Applied sciences; Chemistry; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electronics; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; General and physical chemistry; General, apparatus; Materials science; Methods of nanofabrication; Physics; Self-assembly; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Solubility, segregation, and mixing; phase separation; Surface physical chemistry; Transistors
• ISSN: 0959-9428; 1364-5501
• DOI: 10.1039/b900979e

This study describes the synthesis, characterization and electronic properties of a novel series of soluble thieno[3,2-b]thiophene oligomers (1a and b and 2a and b) for thin film transistor (TFT) applications. All the compounds were synthesized in high yield using Pd-catalyzed Stille or Suzuki coupling reactions and were substituted by two dodecyl groups at the 3- or 4-position of the thiophene unit to ensure the solubility for facile device fabrication. Aryl units such as phenyl and naphthyl were used for 'endcapping' to provide stability against oxidation. The design of these materials has focused on their self-assembly and solution processability. All the compounds have been characterized by @u1H, @@u13@C NMR, and elemental analysis. Their electronic and optical properties were investigated using UV-Vis and photoluminescence spectroscopy, cyclic voltammetry, thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC). High-resolution STM images of 1a and 2a adsorbed on HOPG revealed highly ordered self-organized domains. Two-dimensional wide-angle X-ray scattering (2D-WAXS) was used to study the solid state packing of 1a and 2a. Top-contact OTFT devices from 1a were prepared by spin coating and showed promising behaviour with mobilities up to 3.11 x 10@@u-2@ cm@u2V@@u-1@ s@@u-1@ and on/off ratios up to 10@u4.