Electroluminescence in Organic Films with Three-Layer Structure

Abstract

We have succeeded in the fabrication of a stable organic electroluminescent (EL) device with a three-layer structure; hole transport layer/emitting layer/electron transport layer. The EL device was prepared by vacuum evaporation. Efficient carrier double injection into the emitting layer was realized by the use of separate hole and electron transport layers. Bright EL emission was observed in a darkened room at the dc bias voltage of 50 V. Stable emission lasted for more than five hours at this condition. The emission spectrum could be changed with variation of the organic material for the emitting layer.

Optical Fiber Sensors: An Overview

“…The research on these new fluorescent materials has contributed to the development of organic lightemitting diodes (Akcelrud, 2003;Friend et al, 1999;Kraft et al, 1998). Organic thin-film electroluminescence devices were developed in the 1980s by Tang and Van Slyke (Tang & Van Slyke, 1987) and Saito and Tsutsui et al (Adachi et al, 1988).…”

“…In general, conjugated polymers have become an important class of materials employed in a wide variety of applications, including light-emitting diodes (LEDs) (Adachi et al, 1988;Akcelrud, 2003;Friend et al, 1999;Kraft et al, 1998;Tang & Van Slyke, 1987), light-emitting electrochemical cells (LECs) (Pei et al, 1995), plastic lasers (Hide et al, 1997), solar cells (Gunes et al, 2007), field effect transistors (FETs) (Sirringhaus, 2005), and more recently, chemical or biological sensors (Achyuthan et al, 2005;Castrellon-Uribe et al, 2009;Liu & Bazan, 2004;McQuade et al, 2000;Pinto & Schanze, 2002;Thomas et al, 2007).…”

Bipyridyl substituted triazoles as hole-blocking and electron-transporting materials for organic light-emitting devices

“…On the other hand, there have been scarcely reports on ET organic semiconducting amorphous materials with high performance (high-speed transportation of electrons, easy injection of electrons from the cathode, and good operational durability). [13] Tris (8-hydroxyquinolinato) aluminum(III) (Alq), which is the historical material reported in the first bright OLED by Tang et al in 1987, [16] is still conventionally used as an ET material regardless of its slow electron mobility [17] because it exhibits high operational durability.…”

Properties of materials for organic light emitting diodes

“…3,8,24,33,34 Fluorescence is a spin-allowed radiative decay process from a singlet excited state back to the (singlet) ground state, S 0 . Since there is no change in the molecular spin state, electronic relaxation proceeds unhindered and so fluorescence is characterised by very short emission lifetimes, often on the order of nanoseconds.…”