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Indexed by:期刊论文

Date of Publication:2009-04-01

Journal:OPTICAL MATERIALS

Included Journals:SCIE、EI

Volume:31

Issue:6

Page Number:889-894

ISSN No.:0925-3467

Key Words:Near-infrared; Organic light-emitting diodes; Electroluminescence

Abstract:Red and near-infrared (NIR) organic light-emitting devices (OLEDs) were fabricated based on Tetra (2-Isopropyl-5-methylphenoxyl) substituted metal-free phthalocyanine (Tetra-H(2)Pc). The devices were fabricated by vacuum deposition and spin coating methods. The electroluminescence (EL) intensity at about 910 nm in the devices based on Tetra-H(2)Pc was increased by about 14 times compared with the intensity at about 930 nm in the devices based on unsubstituted metal-free phthalocyanine (H(2)Pc) in the same device structures. The improvement in the EL intensity was attributed to the large steric hindrance of non-peripheral phenoxyl substituent of Tetra-H2Pc. It was found that the NIR EL spectra of the doped devices exhibited a strong dependence on the concentration of Tetra-H2Pc. The emission at 740 nm was from Tetra-H(2)Pc monomer, while the emissions around 910 nm and 870 nm were from excimer or higher aggregated species. (C) 2008 Elsevier B.V. All rights reserved.