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RESEARCH PRODUCT
Morphological, electrical and optical properties of organic light-emitting diodes with a LiF/Al cathode and an Al-hydroxyquinoline/diamine junction
Giuseppe BaldacchiniRosa Maria MonterealiAngelo PaceFrancesco MichelottiSalvatore GambinoStefano LoretiS. Gagliardisubject
ChemistryMechanical EngineeringMetals and AlloysAnalytical chemistryalq3; electroluminescence; organic diodes; thin filmsLithium fluorideBiasingElectroluminescenceCondensed Matter PhysicsCathodeElectronic Optical and Magnetic Materialslaw.inventionchemistry.chemical_compoundMechanics of MaterialslawMaterials ChemistryOLEDElectric currentLuminous efficacyDiodedescription
Abstract We report the results of the morphological, electrical and optical characterisation of double-layer Alq3-based organic emitting diodes with a lithium fluoride (LiF)/Al cathode. A detailed electron microscopy investigation of their cross-section shows the presence of LiF isolated grains underneath the Al film. Due to the introduction of the LiF layer, luminance was larger than 30,000 cd/m2 at a bias voltage VB=25 V with a maximum external luminous efficiency as large as 46 lm/W at VB=20 V. Performing on/off VB cycles at a very low frequency, each time a recovery of the initial electric and luminous performance was observed. The non-exponential decay of both electric current and luminance during each on-cycle has been interpreted as the signature of dispersive transport controlled by multiple trapping on localised states in an amorphous system.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2004-06-01 |