The short device lifetimes of blue PhOLEDs: insights into the photostability of blue Ir(iii) complexes

Using Ir(iii) complexes as dopants in phosphorescent organic light-emitting diodes (PhOLEDs) is the most successful strategy to attain long-lasting and highly-performant electroluminescent devices. Whilst highly efficient blue PhOLEDs are accessible, their limited operational lifetimes still restraint their practical use in lighting and displays. These short lifetimes are directly related to the low intrinsic photostability of blue Ir(iii) complexes. This work uses first principles to unveil the mechanisms of degradation of blue phosphors arising from energetically hot excited states (≅6.0 eV), and to propose a strategy for improving the stability of blue phosphors.