BaZrO₃ perovskite nanoparticles as emissive material for organic/inorganic hybrid light-emitting diodes

In the present work we have demonstrated double-channel emission from organic exciplexes coupled to inorganic nanoparticles. The process is demonstrated by yellow-green emission in light-emitting diodes based on organic exciplexes hybridized with perovskite-type dispersed BaZrO₃ nanoparticles. Such double-channel emission provides a broadening of the electroluminescence spectrum and a resultant yellow-green emission color of the device. We have realized an energy transfer from the exciplexes arranged by the interface between two organic layers and the spherical-shaped BaZrO₃ nanoparticles randomly deposited on the organic interface constructed of the tris(4-carbazoyl-9-ylphenyl)amine and 4,7-diphenyl-1,10-phenanthroline molecules. The fabricated device exhibits a current efficiency value of 3.88 C d/A, maximum brightness of 3465 cd/m² (at 15 V), and external quantum efficiency of about 1.26%. In order to estimate the efficiency of the energy transfer from the exciplex to the BaZrO₃ nanoparticles we have applied the Förster model for the dipole-dipole energy transfer accounting for the mutual overlap of the exciplex emission spectrum and the absorption spectrum of the BaZrO₃ nanoparticles.