EUROLED: Polymer films from evaporated monomers and their use in organic light emitting devices

• Research unit: EU RFP
• Project number: 97.0402

Key words (English)

Organic light emitting devices; vapor deposition polymerization; STM based imaging; luminescence excitation and spectroscopy; charge carrier injection; electronic excitations in organic materials; device physics in OLEDs; electrical and optical model

Alternative project number (English)

EU project number: FMRXCT970106

Research programs (English)

EU-programme: 4. Frame Research Programme - 10.1 Stimulation of training and mobility

Short description (English)

See abstract

Partners and International Organizations (English)

University of Sheffield (UK), University of Sassari (I), Techn. Univ. Graz (A), Univ. Bayreuth (D), Instituto Nazionale per la fisica della Materia (I), Institut Charles Sadron (F)

Abstract (English)

In the framework of the EUROLED project both fundamental and applied research in the emerging field of organic light emitting devices (OLEDs) have been carried out on a European scale. The main objectives of the EUROLED Network were the development of vapor deposition polymerization (VDP) for use in the fabrication of efficient organic light emitting diodes (OLEDs) and to improve the European knowledge base concerning the fundamental processes in OLEDs that determine efficiency and lifetime.
The network was extremely fruitful in terms of scientific results, training of young researchers and collaborations between the network groups.
A number of distinguished achievements have been obtained including successful demonstration of blue, polarized OLEDs with a high polarization ratio, fabrication and characterization of OLED microcavities and optical stimulated lasing. Furthermore, the mechanisms of energy transfer in polyfluorene doped films was fully identified by using ultra-fast time-resolved spectroscopy. A novel STM based technique was developed and successfully applied in the spectroscopy of organic materials and interfaces. New classes of materials, in particular electron transport layers, have been synthesized and characterized. Via angle resolved ultraviolet photoelectron spectroscopy the band structure of highly ordered diphenyloxadiazoles has been experimentally determined.
The focus of IBM's activities in the network was in the application of the newly developed STM z-V spectroscopy technique which allows the probing of the electronic level alignment at metal-organic material interfaces and on charge carrier injection spectroscopy into amorphous organic films. A highlight was the first demonstration of vapor deposition polymerization of PPQ under UHV conditions. The focus in the last year was centered on the device physics of multilayer organic light emitting devices, in particular on a quantitative understanding based on sophisticated electrical and optical modeling.
Main results of the EUROLED network were presented at the ECOER-1 conference held in Potsdam (November 19 -21), demonstrating that the network has clearly acquired a very high level of scientific quality and international leadership in both fundamental and applied research.

To summarize, during the EUROLED network period novel experimental methods for OLED device fabrication and characterization techniques have been developed and demonstrated and deeper insight into the physics governing these novel devices by means of analytical and numerical simulations was gained. The collaboration among the network partners was very stimulating, open and continues to be fruitful.

References in databases (English)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 97.0402