Nanoscale observation of failures in organic light-emitting diodes

Abstract

We introduce a simple and low-cost method for examining interface morphologies of nanoscale organic layers to demonstrate failure modes in organic light-emitting diodes. Cross-sectional scanning electron microscopy of nonencapsulated organic light-emitting diodes, fabricated on silicon wafers using poly[1-methoxy-4-(2-ethylhexyloxy-2,5-phenylvinylene)] as an emitting layer, were examined after failure. Two primary modes of failure are easily identified in the micrographs. The first process involves the formation of “black spots” caused by the pyrolitic carbonization of the emitting layer’s polymer, and the second is the delamination and concurrent swelling of the cathode.