Share Email Print

Proceedings Paper

Light-emitting diodes with naphtalimide side-chain polymers: basic properties and role of polymer thickness in two-layer devices
Author(s): Franco Cacialli; Cecile-Maria Bouche; Pierre L. Le Barny; Hugues Facoetti; Francoise Soyer; Philippe Robin; Richard H. Friend
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

We report the fabrication of efficient green light-emitting diodes using a side-chain polymer based on a high-electron affinity (EA) naphtalimide moiety (PNI). The chromophore is attached to a polymethacrylate backbone through a spacer, and emits in the green with high efficiency. In single-layer light-emitting diodes (LEDs), we find that the electroluminescence (EL) efficiency is not limited by Al cathodes as for poly(p-phenylene-vinylene), PPV, and we attribute this to the increased EA. We report maximum internal efficiencies of about 1.7 percent for Ca and 0.9 percent for Al in double-layer devices where PPV serves as both Hole-injector and emitter. Compared to some oxadiazole based electron injection/transport layer, PNI gives higher efficiencies at high currents, and longer lifetimes. Tuning of emission in the red is possible by dye-doping the PNI and causing the emission to happen in this layer. We discuss the properties of the different device configurations with a view to the electronic structure of the materials and in particular to the influence of the thickness of the individual layers on efficiency and driving conditions.

Paper Details

Date Published: 1 December 1997
PDF: 8 pages
Proc. SPIE 3148, Organic Light-Emitting Materials and Devices, (1 December 1997); doi: 10.1117/12.284173
Show Author Affiliations
Franco Cacialli, Cambridge Univ. (United Kingdom)
Cecile-Maria Bouche, Thomson-CSF (France)
Pierre L. Le Barny, Thomson-CSF (France)
Hugues Facoetti, Thomson-CSF (France)
Francoise Soyer, Thomson-CSF (France)
Philippe Robin, Thomson-CSF (France)
Richard H. Friend, Cambridge Univ. (United Kingdom)

Published in SPIE Proceedings Vol. 3148:
Organic Light-Emitting Materials and Devices
Zakya H. Kafafi, Editor(s)

© SPIE. Terms of Use
Back to Top