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Polyfluorene-Based Push−Pull Type Functional Materials for Write-Once-Read-Many-Times Memory Devices
Ist Teil von
Chemistry of materials, 2010-08, Vol.22 (15), p.4455-4461
Ort / Verlag
American Chemical Society
Erscheinungsjahr
2010
Link zum Volltext
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
A highly soluble polyfluorene-based copolymer containing electron-rich triphenylamine (TPA) and electron-poor 9,9-bis(3,4-bis(3,4-dicyanophenoxy)phenyl side chains in the C-9 position of the fluorene unit was synthesized under Yamamoto conditions. By applying 306 nm as excitation wavelength, the resultant polymer exhibits strong photoluminescence with maximum emission peaks centered at 413 and 433(sh) nm in chloroform. The calculated highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), energy bandgap, ionization potential, and electron affinity are −5.66, −3.44, 2.22, 5.92, and 3.70 eV, respectively. The as-fabricated polymer film exhibited typical stable write-once-read-many-times (WORM) memory characteristics, which are desirable for ultralow-cost permanent storage of digital images. The currents in both ON and OFF states did not show any degradation, suggesting good device stability. The ON/OFF current ratio observed in the sweep I−V characteristics at +1.0 V is 6.1 × 103. The conduction mechanism through ITO/polymer/Al device is discussed.