Low frequency noise measurement and analysis of organic light emitting diode

Abstract

Organic light emitting device (OLED) low frequency voltage and luminance noise were measured and investigated. 1/f Gaussian noise from device bulk materials and an excessive frequency related part of noise related to device interfaces or defects and traps contributed to device voltage noise. The excessive part of noise increase much faster during device stress. This shows that the interface defects and traps related degradation is much faster. Optical noise observation is a direct reflection of polymer intrinsic degradation. A correlation between current noise and dark spot formation is established too. The 1/f noise slope is correlated to the dark spot growth rate and lifetime. A larger 1/f noise slope generally leads to a faster dark spot growth rate and shorter lifetime. The noise measurement can be a powerful tool to predicate device lifetime and degradation behavior.