Electrically active polymer compositions and their use in efficient, low operating voltage, polymer light-emitting diodes with air-stable cathodes
US5965281A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 3, 1997 |
| Grant date | Oct 12, 1999 |
| Priority date | — |
| Expiry date | Jul 3, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S430/102
Abstract
The addition of a highly polarizable additive such as an organic anionic surfactant to an electrically active polymer improves the electrical properties of the polymer. When such an additive is added to an electroluminescent organic polymer this mixture can be used in diodes having an anode contacting a layer of this mixture as the active light-emitting layer and an air-stable metal cathode having a work function larger than 4 eV. The external efficiency and brightness versus voltage are significantly improved compared to results obtained with the same electroluminescent polymer used alone with high work function (>4.0 eV) metal cathodes. Specifically, device performance with indium/tin-oxide (ITO) as the anode, poly(2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene), MEH-PPV, as the electroluminescent polymer, lithium nonylphenoxy ether sulfate as the surfactant additive and aluminum as the cathode is comparable to or better than that obtained with high performance devices using calcium as the cathode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.