OLED achieves light yield of 60 lumens per watt

The OLED also meets the international Energy Star SSL Standard with regard to colour requirements.

The OLEDs contain phosphorescent metal complexes as emitter materials and customised complementary materials, which ensure optimum constancy of the colour temperatures.

That means that, owing to the use of new materials, the diodes are very colour-stable even when there are variations in luminous intensity.

Unlike conventional filament bulbs, OLEDs do not become hot when emitting light and less energy is lost through radiated heat.

Laboratory results show that the new OLEDs are five times as efficient as filament bulbs and up to 50 per cent more efficient compared with standard low-energy lamps.

OLEDs consume much less electricity than conventional sources of light, so consumers will in future be able to cut their electricity costs with OLEDs.

BASF is dealing with the material side of the OLEDs and, within the framework of the OLEDs for Applications on the Lighting Market (OPAL) project, is developing the optimum component structures in partnership with Philips and Osram.

In future, organic light-emitting diodes will be suitable for general lighting as flat sources of light - for offices or as decorative lighting in stores.

They not only offer the potential of being more economical than conventional low-energy bulbs in terms of electricity consumption, but are also capable of being used in a variety of ways as flat, transparent and, in future also, flexible sources of light.

They will provide new opportunities in terms of design and performance - in part owing to newly developed semiconductor materials from BASF.

Dr Karsten Heuser, OPAL co-ordinator and director OLED lighting technology at OSRAM Opto Semiconductors, said: 'The challenge now is to optimise the life of these OLED tiles, especially by stabilising the blue emitters.'