Monodisperse Oligofluorenes Forming Glassy-Nematic Films for Polarized Blue Emission

Journal Article · Sat Jan 04 04:00:00 EST 2003 · Chemical Materials

DOI:https://doi.org/10.1021/cm0208859· OSTI ID:807066

Geng, Y ^[1]; Culligan, S W; Trajkovska, A; Wallace, J U; Chen, S H

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1. Laboratory for Laser Energetics, University of Rochester, Rochester, NY

The first series of monodisperse glass-forming, nematic oligofluorenes was synthesized following a divergent-convergent approach. Both chain length and pendant structure were found to affect solid morphology and phase transition temperatures. With optimized structural parameters, a Tg close to 150C and a Tc beyond 375C were achieved. This material class is characterized by its ability to form monodomain glassy nematic films via spin-coating, thermal annealing at 10 to 20C above Tg for 15-30 min, and cooling to room temperature without encountering crystallization. The absorption and emission dichroic ratios of 80-90-nm-thick films increase from 7 to 17 with an increasing molecular aspect ratio, while the photoluminescence quantum yield varies erratiexecy from 43 to 60%. Superior stability of emissive color and of emission dichroic ratio and that against thermally activated crystallization were also demonstrated through prolonged heating of a film at 10C above Tg under argon.

• Research Organization: Laboratory for Laser Energetics, University of Rochester (US)
• Sponsoring Organization: (US)
• DOE Contract Number: FC03-92SF19460
• OSTI ID: 807066
• Report Number(s): DOE/SF-19460-469; 1340; 2002-112
• Journal Information: Chemical Materials, Journal Name: Chemical Materials Journal Issue: 2 Vol. 15
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION
ANNEALING
COLOR
CRYSTALLIZATION
GLASS
HEATING
MORPHOLOGY
ORGANIC FLUORINE COMPOUNDS
PHOTOLUMINESCENCE
TRANSITION TEMPERATURE