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The authors report a simple approach to reduce power consumption of organic light-emitting diodes. Introducing a 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline layer into the emissive layer can dramatically improve the carrier recombination efficiency. The presence of an interlayer of tris(8-quinolinolato)aluminum (Alq3) within the hole-transport layer also gives rise to the similar phenomenon. Furthermore, they modified the anode with the ultrathin hexadecafluorocopper phthalocyanine layer in order to further enhance the electroluminescent properties. They obtained the high performance light-emitting diodes using Alq3 as the emissive layer with a high current efficiency of 7.63 cd/A and a low turn-on voltage of 2.89 V. [ABSTRACT FROM AUTHOR]

We prepared a large quantity of multiwall nanotubes with intramolecular junctions (CNx/C) by pyrolysis of iron phthalocyanine with or without an inlet of ammonia gas. The nanotubes consist of two sections, one section made of carbon nitride featuring bamboo-like structure and the other one made of carbon featuring empty hollow cylinder structure, and thus the intramolecular junctions were formed in the middle as a result of being doped or undoped with nitrogen. Nanodiode based on a single CNx/C junction shows reproducible rectifying behavior with a rectification ratio of 1.3×103 at ±2 V. In addition, the nanodiode demonstrated as a half-wave rectifier worked at an input sine wave of 1 kHz. Two CNx/C junctions were configured together to exhibit functions of OR and AND logic gates. Moreover, after substituting the wave-detection silicon diode in common transistor radio set with our nanodiode, the radio set still worked normally, representing an important step toward the potential application for nano-scale devices. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The solubility of fullerene (C[sub 60]) is improved by combining it with an alkyl group of substituted copper (II) phthalocyanine (CuPc) through Diels-Alder reaction. Optical limiting properties of this compound were investigated by using a double frequency Nd:YAG laser system at a wavelength of 532 nm with pulse duration of 45 ps. The results show that there are two separated conjugation systems in this kind of molecule. Both of them independently contribute to the reverse saturable absorption. Broadband optical limiting materials might be designed based on the combination of various optical limiting molecules through covalent bonds. Phase separation problems existing in the mixture of various materials can be avoided. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]