Metal Migration Leads to Breakdown of Organic LEDs

Using secondary ion mass spectrometry, researchers at the Institute of Materials Research and Engineering in Singapore have found that some organic LEDs degrade because of metal migration at the indium-tin oxide/polymer interface.

As reported in the March 25 issue of Applied Physics Letters, this migration of calcium from the cathode and indium from the anode results in metal protrusions at the interface that channel large local electrical currents. The excess current causes the polymer layer to decompose and to form volatile species and carbonyl groups that quench luminescence from the polymer.