28‐4: Invited Paper: Effects of Guest Clustering Morphology in Phosphorescent OLEDs

Abstract

In this work, we report results of clustering studies across a range of length scales in Ir(ppy)3: mCBP organic light emitting diodes (OLEDs) deposited at a variety of substrate temperatures. We identify signatures of the light‐emitting guest molecules clustering at the local scale using atom probe tomography and large‐scale clusters using high‐angle annular dark‐field scanning transmission microscopy (HAADF‐STEM). Changes of to the small‐ and large‐scale clustering behavior are consistent with changes to conductivity and exciton annihilation processes observed at different substrate deposition temperatures.