Recent progress in polymers for electroluminescence: Microcavity devices and electron transport polymers

In this paper we briefly review the status of polymer electroluminescence and then report recent work on microcavity polymer devices and on electron transport polymers with electron-deficient nitrogen-containing aromatic moieties. Results are presented for electroluminescence and photoluminescence from microcavity structures containing a poly(2,5-dialkoxy-p-phenylene vinylene) conjugated polymer. Strong spectral narrowing from 108 nm full width half maximum to 34 nm in electroluminescence and from 128 nm to 16 nm in photoluminescence, marked enhancement of the peak emission intensity and clear angular dependence of the peak emission wavelength are observed. These are all characteristic signatures of the modification of spontaneous emission properties in microcavity structures and open the way to studies of microcavity physics in polymer based devices. A non-ether poly(phenyl quinoxaline) and poly(2,6-pyridine vinylene-co-2,5-diheptoxy-p-phenylene vinylene) have been investigated as new electron transport polymers and we present results for their operation in both single and bilayer polymer devices. Additional target polymers for electron transport functionality are described.