Patterned growth of vertically aligned organic nanowire waveguide arrays

Vertical nanowire arrays were prepared from an organic dye compound, 1,5-diaminoanthraquinone (DAAQ), on various types of substrates by a facile physical vapor transport method. It was found that the DAAQ grows much faster on the substrates with higher surface energies. Therefore, patterned growth of the nanowire arrays was achieved by modifying the substrate surfaces both geometrically and chemically to induce selective growth in areas of higher surface energies. The DAAQ nanowires can serve as nanosized active optical waveguides that allow the locally excited photoluminescence to propagate along the length of the wires. The low-loss waveguide propagation modes along the nanowire were observed experimentally. The nanowire arrays can be integrated directly with a portable fiber optics spectrometer for chemical vapor sensing.