Light-emitting rubrene nanowire arrays: A comparison with rubrene single crystals

This is a report on a new method of growth of a light-emitting rubrene nanowires array with diameters of 200 ± 10 nm by using organic vapor transport through Al₂O₃ nanoporous templates. Nanometer-scale laser confocal microscope (LCM) photoluminescence (PL) spectra and crystalline structures of the rubrene nanowires are compared with those of rubrene single crystals prepared with the same experimental conditions without the template. In the LCM PL spectra it is observed that the PL spectra and intensity varies with the detecting positions because of the crystal growth characteristics of the rubrene molecules. A single rubrene nanowire has a wider LCM PL band width than that of the rubrene single crystal. This may originate from the light emissions of the mixed polarized bands due to additional new crystallinity in the formation of the nanowires. From the current-voltage characteristic curves, the semiconducting nature of both the rubrene nanowires and single crystals is observed.