Microscopy Techniques Image Organic LED Bubble Formation

Scientists from the Institute of Materials Research and Engineering in Singapore have examined the formation of dark spots in organic LEDs caused by dome-shaped bubbles at the interface between an emissive and nonemissive diode layer.

Using the combination of a Nikon E600 light microscope, a time-of-flight secondary ion mass spectrometry instrument and a Jeol JSM-6700F scanning electron microscope, they observed that the bubbles are the result of electrode roughness, local current concentration and heating that leads to material degradation. In a description published in the Jan.14 issue of Applied Physics Letters, the researchers suggest that stabilizing and smoothing the interface can reduce formation of such dark spots.