| Organic Semiconductors. A new frontier in the field of organic light-emitting materials is constituted by crystalline organic semiconductors. These materials offer several advantages compared to amorphous polymer thin films commonly employed in optoelectronic applications, since in organic crystals the amount of structural defects can be significantly reduced, thus leading, for instance, to high charge transport mobility. These materials show also intriguing optical properties: self-waveguiding of emitted light, optical anisotropy, and superradiance. Read more |  |  | Energy Transfer in Organic and Hybrid Blends. Determining and controlling the inter-component excitation conversion in light-emitting organic blends and hybrid organic-inorganic materials is a key factor for predicting the composite luminescence properties and for the operation of many opto-electronic devices. Blend composition, morphology and temperature can be effectively used to enhance the nonradiative transfer rate. Read more | | |  | Organic-based Microcavities. Vertical cavity surface-emitting lasers (VCSELs) are constituted by an active polymer layer embedded between two high-reflectance mirrors. VCSELs offer the possibility of realizing, by a single-step process, multidimensional laser arrays, with low-divergence beam emitted perpendicularly to the substrate -particularly suitable for coupling with optical fibers and for telecommunication applications. The effective optical field confinement inside the cavities allows the observation of QED effects such as the strong coupling between excitons of the organic active layer and cavity photons, leading to the formation of polaritons. Read more | | | | | Organic Distributed Feedback Lasers. Plastic and flexible DFB lasers are fabricated by room temperature nanoimprinting lithography and electron beam lithography. The realization of DFB laser is accomplished by direct dry pressing of the active polymer layer. The high emission efficiency, typical of conjugated polymers, is preserved, and single mode emission can be achieved in the visible and near infrared range. The devices are characterized by strongly polarized emission and a lifetime, upon UV photo-pumping, of thousands of laser exciting pulses. Read more | | | | | Polymer Waveguides. Active polymer waveguides constitute low cost alternatives for the realization of optical amplifiers and lasers. In these waveguides the energy transfer between the host and guest polymers can be exploited to significantly reduce the self-absorption, thus providing very low loss coefficients and highly polarized emission. Read more |
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