Chunyu Ma

1.1μm near-infrared electrophosphorescence from organic light-emitting diodes based on copper phthalocyanine

We demonstrated near-infrared organic light-emitting devices employing copper phthalocyanine (CuPc) doped into 4,4′-N,N′-dicarbazole-biphenyl (CBP). Room-temperature electrophos-phorescence was observed at about 1.1μm due to transitions from the first excited triplet state to the singlet ground state (T1-S0) of CuPc. There existed very weak emission of CBP from undoped devices, and at lower doping concentrations (⩽12wt%) the driving voltages of doped devices were higher than that of undoped devices. The results indicated that Forster [Ann. Physik. (Leipzig) 2, 55 (1948)] and Dexter [J. Chem. Phys. 21, 836 (1953)] energy transfers play a minor role in these devices, and direct charge trapping appears to be the dominant mechanism.

Synthesis and Characterization of a New Metal-free Azaphthalocyanine Containing Four Peripheral Ion Jacks

A synthesis of a new 1,10-phenanthroline-appended metal-free azaphthalocyanine(azaPc), which is generated from precursor, 10,12-diimino-11 H-pyrrolo[3,4-b]dipyrido[3,2-f2,3-h]quinoxaline, is described. This azaPc is purified by absolute methanol in a Soxlet apparatus, then under high vacuum (10 - 4 Pa) and is unequivocally characterized by its elemental analysis and spectrometry.

Synthesis and electrochemical characterization of β-tetra-(2-isopropyl-5-methylphenoxylphthalocyaninato)titanium(IV) Oxide

A β-4-(2-isopropyl-5-methylphenoxylphthalocyaninato)titanium(IV) oxide (TiOPc) was prepared and characterized by MS, 1H NMR, and elemental analysis. Cyclic voltammograms show that this TiOPc has two quasi-reversible reduction couples and two quasi-reversible to irreversible oxidations processes. The first reductions are two-electron processes, confirmed by spectroelectrochemistry to be due to TiIVPc2−/TiIIIPc3− redox processes. The second reductions are two-electron processes during which TiIIIPc3− was reduced to TiIIIPc5− species. Spectroelectrochemistry showed that oxidation occurs at the ring during the first oxidation. However, spectroelectrochemistry also showed that upon the second oxidation, the molecule decomposes. Chronocoulometry confirmed transfer of two electrons at the first and second reduction steps.