title: Organic semiconducting materials from sulfur-hetero benzo[k]fluoranthene derivatives: synthesis, photophysical properties, and thin film transistor fabrication.
abstract: A new family of air-stable sulfur-hetero oligoarenes based on the benzo[k]fluoranthene unit has been facilely developed as the active materials for thin film organic field-effect transistors. The Diels-Alder reaction between cyclopentadienone 1 and 2,2'-(ethyne-1,2-diyl)bisthiophene followed by decarbonylation afforded fluoranthene derivative 2. After bromination and subsequent substitution through Suzuki coupling reaction, the FeCl3-oxidative cyclization produced sulfur-hetero benzo[k]fluoranthene derivatives 8-12. In dilute chloroform solution, the absorption and emission behaviors of 2 and 4-7 showed characteristic features of the fluoranthene units, while their emission lambda(max) red-shifted with an increase of the effective conjugation length. The steady state absorption and emission spectra of these newly synthesized compounds were thoroughly investigated and discussed. Thin film organic field-effect transistors (OFETs) using 8-11 as active materials were fabricated in a "top contact" configuration. Substituents at the skeleton play an important role in the film morphologies, which lead to different mobilities, while the charge mobilities of 8-11 from OFETs were improved after thermal annealing of the thin films. A carrier mobility as high as 0.083 cm(2) V(-1) s(-1) and current on/off ratio of 10(6) were achieved through vacuum-deposited film followed by the thermal annealing process from 11.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, College of Chemistry, Peking University, Beijing 100871, China.
authors.forename: Qifan
authors.initials: Q
authors.lastname: Yan
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Ben-Bo
authors.initials: BB
authors.lastname: Ni
authors.forename: Yuguo
authors.initials: Y
authors.lastname: Ma
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Jian
authors.initials: J
authors.lastname: Pei
authors.forename: Yong
authors.initials: Y
authors.lastname: Cao