Multimodal\nMicroscopy of Partially Oriented <i>para</i>-Hexaphenylene\nNanoaggregates

Organic molecular beam deposition (OMBD) of <i>para</i>-hexaphenylene (p6P) on polycrystalline platinum results in the formation\nof unique nanoaggregates, predominantly as nanofibers and nanoribbons.\nThese aggregates exhibit distinct morphological properties, as revealed\nby atomic force microscopy (AFM). Grazing incidence X-ray diffraction\n(GIXD) confirms the p6P herringbone structure as partially oriented\naggregates with a bias of previously observed contact planes parallel\nto the substrate. The optical properties of the aggregates are analyzed\nusing polarization microscopy, fluorescence microscopy, and Raman\nmicroscopy to distinguish three different aggregate types with a focus\non aspects such as molecule orientation within the aggregates, including\nthose lying and standing upright. Polarized microscopy indicates that\nthe molecular orientation within the fluorescing, fiber-like aggregates\nis generally perpendicular to the long fiber axis and parallel to\nthe substrate, which seems not to be the case for the other two types.\nThis finding is crucial for applications utilizing p6P’s polarized\nemission, such as in photonic and optoelectronic devices.