Abstract
Recent results of two types of mesoscopic-structured excitonic systems are reported. First is the synthesis of CdSe and CdSe/ZnS nanocrystals by pyrolysis of organometallic reagents in coordinating solvents TOPO-TOP and/or TOPO-TOP-HDA mixtures and their optical properties are characterized. Microscopic passivation by ZnS overcoating provides enhancement of their radiative recombination process, i.e. maximum quantum efficiency reaches over 50% for the moment. To increase the range of the sizes of obtained nanocrystals, 2-step injection of Cd/Se precursors seems effective. The second is J-aggregates by PIC-Cl dye molecules prepared in thin PVA polymer films. In specific condition, also in PVA as in ionic PVS, coherent J-segments seem gathered together to form sub-micron width fibril-like structures. Microscopy and spectroscopy of individual fibril structures are described.