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Humboldt-Universität zu Berlin - Mathematisch-Naturwissen­schaft­liche Fakultät - SFB 951 - HIOS

Research Program

Motivation | Topics | Application Perspectives

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The elemental optoeletronic functions to be realized by our HIOS are light absorption and emission, energy transport, charge separation and transport, optical optical switching, and plamonic emission or amplification, all in - or scalable to - meso- and nanoscopic dimensions.

Examples include:

High brightness directional light emitters and lasers

Future high integration densities call for nanoscale light emitters that cover wide wavelength ranges, readily available through conjugated organic molecules, and that operate at high excitation densities, for which inorganic semiconductors are predestined. The HIOS proposed here can be used in the following approaches:

  • Excitation in an inorganic semiconductor, realized by optical or electrical pumping, is transferred with high efficiency by non-radiative energy transfer to a conjugated organic material where photon emission subsequently takes place. Depending on the architecture, such HIOS might be capable of either white light emission or coherent narrow-band lasing.
  • Metal nanostructures appropriately arranged in proximity of the conjugated organic light emitter are utilized for further local enhancement of energy transfer, potentially even for a single conjugated molecule. Ultimately, lasing through surface-plasmon amplification by stimulated emission in HIOS structures with sub-100 nm size dimension may be achieved.

Efficient nanoscale light absorbers and converters to electrical energy

Efficient light harvesting and subsequent conversion to electrical energy in nanoscale dimensions is highly challenging because of the small active volumes. HIOS can tackle this problem through:

  • Exploiting the wide absorption energy range of conjugated organic materials and their high absorption cross-sections, the latter further increased by suitable placement of plasmonic nanoantennae.
  • Subsequent charge separation at the interface between the conjugated organic materials and an inorganic semiconductor may result in unprecedented light-to-current conversion efficiency, because (a) interface energy levels can be adjusted favourably toward this function with great flexibility and (b) the fast charge delocalization and high charge carrier mobility in inorganic semiconductors facilitates efficient transport of charges away from the generating interface.

Nanoscale non-linear optical switches with low power consumption

Data processing in the optical domain is superior to electronic circuitry with respect to speed and bandwidth. Shrinking of existing device designs to dimensions of a few optical wavelengths is difficult because non-linear optical properties of neither inorganic semiconductors nor conjugated organic materials scale appropriately. HIOS provide an alternative route. Hybrid exciton states of the conjugated organic materials and the inorganic semiconductor will allow for all-optical nanoscale switches with exceptionally low power consumption and, in parallel, ultrafast response times. Similar expectations apply for electro-optical switching elements.

Institutions:        FHI-Logo        HZB-Logo          Uni Potsdam-Logo          TU Berlin-Logo         HU Berlin-Logo

            IRIS Logo              Funded by:       DFG Logo