Interface studies of Aluminum, 8-hydroxyquinolatolithium (Liq) and Alq(3) for inverted OLED application

초록

This study examined the interfaces of Alq(3) on a thin 8-hydroxyquinolatolithium (Liq) layer deposited on aluminum using X-ray and ultraviolet photoemission spectroscopy. A thin layer of Liq reacted with the underlying aluminum surface. As a result, the molecular orbital features of Alq(3) shifted to a higher binding energy and a new gap state was created. This effect is believed to lower the barrier height for electron injection. An organic light emitting device with a structure of ITO/ Al/Liq/Alq(3)/NPB/WO3/Al was fabricated. The device performance showed characteristics that were consistent with the results of the photoemission studies. It is proposed that AI/Liq can be used as an efficient electron injection layer for inverted organic light emitting devices. (C) 2008 Elsevier B.V. All rights reserved.

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