Influence of cavity Q-factor on near-infrared emitting microcavity organic light emitting diodes

Abstract

In this work, we fabricated near-infrared emitting MOLEDs with two organic layers. The hole transporting layer was N, N' - di(naphthalene-1-yl) - N,N'- diphenylbenzidine (NPB), while tris(8-hydroxyquinoline) aluminum (Alq) was the emissive and electron transporting layer. The bilayer structure was sandwiched between two silver mirrors. In order to investigate the influence of cavity Q-factor to the emission spectra, devices with different thickness of bottom mirror (anode) were fabricated. The influence of the choice of the bottom mirror (anode) was also investigated, and the devices with copper anode were also fabricated. The devices were characterized by angular dependent electroluminescence, photoluminescence, and transmittance measurements. Possible origins of the observed phenomena are discussed. © 2005 Materials Research Society.