OSRAM has achieved a key milestone in organic light diodes (OLED) research. Researchers at the company have produced a “flexible” OLED, which is claimed to have a record 32lm/W efficiency. Flexible OLEDs will have a broader scope in commercial applications as compared to rigid OLEDs.
In lab tests OSRAM was successful at achieving lighting values of 32lm/W for the flexible OLED – a new peak value. Source: OSRAM
Increasing the efficiency of OLEDs has been a key challenge in the OLED development sector. OSRAM’s record OLED efficiency was technically made possible by a peculiar electrode design using a 100 µm thick steel foil as a substrate for the OLED. As the thin foil is opaque, light will not pass through it like it does in a rigid OLED, but will be emitted on the upper surface. This technology is called “Top-Emitter” technology and complicates the design of high-quality white light.
OSRAM researchers tested an OLED sample having a large surface. The brightness was set at 1,000 cd/m². The measurements were performed in an integrating sphere in the absence of macroextractors such as lens assemblies, which manipulate the measurements by increasing the light yield.
OSRAM recently achieved an efficiency value of 87 lm/W in the traditional glass version, which is almost equal to that of a fluorescent lamp. OLEDs are nothing but semiconductors which can convert electricity to light. The thickness of the illuminating OLED layer is about 400 nm, which is almost a hundredth the thickness of a strand of human hair. These OLEDs can give rise to transparent or neutral white light depending on the material used.
The record efficiency values were achieved as part of the grant project TOPAS2012, which is a joint project of the Federal Ministry of Education and Research that supports OSRAM’s OLED research. The aim of this project is to develop innovative OLEDs so as to make the lighting for the future.