Fig. 4: Device performance of HF devices G – I.

a EL spectra; b EQE versus luminance curves; c current density-voltage-luminance curves and d device stability (at an initial luminance of 1000 cd m−2).
a EL spectra; b EQE versus luminance curves; c current density-voltage-luminance curves and d device stability (at an initial luminance of 1000 cd m−2).