Electroluminescence Properties of IrQ(ppy)(2) Dual-Emitter Organometallic Compound in Organic Light-Emitting Devices

Electroluminescence Properties of IrQ(ppy)(2) Dual-Emitter Organometallic Compound in Organic Light-Emitting Devices

Publication Type:

Journal Article

Source:

Journal of Electronic Materials, Volume 47, Issue 2, p.1490-1496 (2018)

ISBN:

0361-5235

Abstract:

<p>This paper reports the influence of the charge carrier mobility on the electroluminescent properties of a dual-emitter organometallic compound dispersed in two conjugated organic small-molecule host materials and embedded in organic light-emitting devices (OLEDs). The electroluminescent processes in OLEDs are strongly influenced by the host-guest interaction. The charge carrier mobility in the host material plays an important role in the electroluminescent processes but also depends on the triplet-triplet interaction with the organometallic compound. The low charge carrier mobility in 4,4&#39;-bis(N-carbazolyl)-1,1&#39;-biphenyl (CBP) host material reduces the electroluminescent processes, but they are slightly enhanced by the triplet-triplet exothermic charge transfer. The higher charge carrier mobility in the case of N, N&#39;-bis(3-methylphenyl)-N, N&#39;-diphenylbenzidine (TPD) host material influences the electroluminescent processes by the endothermic energy transfer at room temperature, which facilitates the triplet-triplet harvesting in the host-guest system. The excitation is transferred to the guest molecules by triplet-triplet interaction as a Dexter transfer, which occurs by endothermic transfer from the triplet exciton in the host to the triplet exciton in the guest.</p>