In this study, a series of manganese [Mn]-doped zinc oxide [ZnO] hierarchical microspheres [HMSs] are prepared by hydrothermal method only using zinc acetate and manganese acetate as precursors and ethylene glycol as solvent. X-ray diffraction indicates that all of the as-obtained samples including the highest Mn (7 mol%) in the crystal lattice of ZnO have a pure phase (hexagonal wurtzite structure). A broad Raman spectrum from as-synthesized doping samples ranges from 500 to 600 cm-1, revealing the successful doping of paramagnetic Mn2+ ions in the host ZnO. Optical absorption analysis of the samples exhibits a blueshift in the absorption band edge with increasing dopant concentration, and corresponding photoluminescence spectra show that Mn doping suppresses both near-band edge UV emission and defect-related blue emission. In particular, magnetic measurements confirm robust room-temperature ferromagnetic behavior with a high Curie temperature exceeding 400 K, signifying that the as-formed Mn-doped ZnO HMSs will have immense potential in spintronic devices and spin-based electronic technologies.

In this study, we report the preparation of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) micro/nanotubes (M/NTs) by a simple physical vapor deposition (PVD) process, and it was found that tubular structures with a diameter from 300 nm to 5 mm and lengths up to tens of micrometres were obtained on a glass substrate at a deposition temperature of 350-400 C. Detailed studies revealed that PTCDA M/NTs were formed via curling and seaming of a 2D lamellar structure constructed by virtue of the cooperation of some noncovalent interactions such as p-p interactions and H-bonds, and it was a temperature-activated process. Devices based on single PTCDA microtubes with different diameters exhibited resistance decreased by 2 orders of magnitude in reducing hydrazine vapor (even for such a low concentration as 5 ppm). Such a successful application of the PVD process to simple organic molecules and highly efficient performance in devices are expected to provide great opportunities for the formation of diverse functional organic hollow nanostructures.

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