ToF-SIMS of OLED materials using argon gas cluster ion Beam: A promising approach for OLED inspection

Abstract

With the increasing adoption of organic light-emitting diodes (OLEDs), analytical methods and tools for their inspection are becoming an important part of the field. In this study, we analyzed four organic materials for OLEDs by using time-of-flight secondary ion mass spectrometry (ToF-SIMS) with 20 keV Ar cluster ion beam projectiles. The fragmentation ratio was plotted as a function of the size of the Ar cluster ions. We reconfirmed that a larger Ar cluster ion beam, which has lower energy per atom, is more effective for detecting secondary molecular ion signals. However, the fragmentation ratio of 4,4′-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine] (TAPC) showed a different tendency. The reason for this difference was investigated and validated by scanning the cluster ion size and comparing it with other mass spectrometric results. This study demonstrates the potential of ToF-SIMS in combination with a cluster ion beam to verify defects in OLEDs that might occur in the manufacturing process.