Influence of air pollutants on the lifetime of LEDs and analysis of degradation effects

Compared to traditional light sources light emitting diodes (LEDs) provide an increased efficiency and long lifetime, making them the primary choice for many applications. However, these lifetimes are highly dependent on operational conditions like junction temperature, drive current and environmental conditions like the exposure to humidity or air pollutants. This work studies the effects of common air pollutants in different concentrations on the lifetime of commercial LEDs with different packages and analyses the observed degradation mechanisms on the AlGaInN LED chips, the metallization and the package components. A special focus is put on the effects of hydrogen sulfide.