Symmetrical carbazole–fluorene–carbazole nematic liquid crystals as electroluminescent organic semiconductors

ABSTRACT

A series of novel symmetrical carbazole–fluorene–carbazoles has been synthesised using simple and highly efficient reaction pathways. The correlation between their molecular structures, differing in the length of the alkyl chains in the lateral position attached to a 2,7-disubstituted fluorene moiety in the molecular core and/or differing in the length of alkoxy chains at the terminal positions of 2,7-disubstituted carbazole moieties, was investigated. Their mesomorphic behaviour, transition temperatures, energy levels and band gaps were measured. A test organic light-emitting diode incorporating one of these compounds exhibits blue electroluminescence.

GRAPHICAL ABSTRACT

KEYWORDS:

• Nematic liquid crystals
• carbazole
• carbazole–fluorene–carbazole
• electroluminescence
• OLEDs

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The China Scholarship Council and the University of Hull are thanked for their support of a PhD studentship for Guang Hu.