Intramolecular excimer emission as a blue light source in fluorescent organic light emitting diodes: a promising molecular design?

Journal of Materials Chemistry Pub Date: 2012-03-07 DOI: 10.1039/C2JM16774C

Abstract

Intramolecular excimer emission arising from organic molecules as a blue light source in fluorescent Small Molecule Organic Light Emitting Diodes (SMOLEDs) is almost absent from the literature. In this work, three aryl-substituted DiSpiroFluorene–IndenoFluorenes (DSF–IFs 1–3) possessing different fluorescent properties due to their different main emitters have been investigated through a structure–property relationship study. Due to its particular geometry, the rigid DSF–IF platform 2 allows an ‘aryl/fluorene/aryl’ dimer to be preformed in the ground state leading, in the excited state, to a deep blue fluorescent emission through strong π–π intramolecular interactions between the two ‘aryl/fluorene/aryl’ arms. 2 has been successfully used as an emitting layer in a SMOLED with electroluminescence arising from electrogenerated intramolecular excimers and the properties of these excimer-based OLEDs have been compared to those of two model compounds (1 and 3). The simple and non-optimized double-layer device displays a deep blue colour (CIE coordinates: 0.19; 0.18) exhibiting a luminance of 510 Cd m?2 with a luminous efficiency of ca. 0.1 Cd A?1. This work is, to the best of our knowledge, the first rational and comparative study describing an intramolecular excimer based-SMOLED.

Graphical abstract: Intramolecular excimer emission as a blue light source in fluorescent organic light emitting diodes: a promising molecular design
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