Prof. Stefan Schweizer Profile

Rare-earth ions embedded in glassy matrices are promising materials for photon upconversion processes, e.g. to convert near infrared light to frequencies above the band gap of a solar cell to make it available for electrical power generation. One strategy to optimize the efficiency of such upconversion processes is to embed the active ions in a host matrix with minimal losses to non-radiative relaxation. For the model system of trivalent neodymium in fluorochlorozirconate (FCZ) glass it has been shown recently that a uniform growth of BaCl₂ nanocrystals inside such glasses can decrease the probability of multi-phonon relaxation (MPR) drastically, leading to a huge increase in upconversion intensity for monochromatic illumination. To identify the key processes which may enhance or diminish the total upconversion efficiency, a comprehensive description for the optical dynamics of neodymium in FCZ glass ceramics has been developed on the basis of a rate equation system, including ion-photon, ion-phonon, and ion-ion interactions. An effective medium approach is utilized to account for the neodymium located in BaCl₂ nanocrystals or the FCZ glass bulk, respectively. The numerous parameters required to enable for a reliable numerical simulation of the processes are obtained from theoretical approaches like Judd-Ofelt theory, as well as from experimental studies of luminescence decay after femtosecond excitation at various wavelengths and luminescence spectra under cw illumination at 800 nm wavelength. This rate equation model enables for a convenient, self-consistent description of all time-resolved and cw experiments on samples with different neodymium concentration. On this basis, the power dependence of upconversion spectra can be simulated in good agreement with the experimental result for 800 nm cw illumination. The model therefore forms an excellent tool for optimizing the upconversion efficiency of rare-earth doped luminescent material also under realistic (broadband illumination) conditions.

Proceedings Article | 2 May 2012 Paper

Neodymium-doped barium borate glasses as fluorescent concentrators for the infrared spectral range

Marcel Dyrba, Marie-Christin Wiegand, Bernd Ahrens, Stefan Schweizer

Proceedings Volume 8438, 84380Z (2012) https://doi.org/10.1117/12.921771

KEYWORDS: Glasses, Luminescence, Silver, Barium, Solar concentrators, Nanoparticles, Absorption, Annealing, Doping, Near infrared

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Proceedings Article | 2 May 2012 Paper

Fluorescent borate glass superstrates for high efficiency CdTe solar cells

Franziska Steudel, Marcel Dyrba, Stefan Schweizer

Proceedings Volume 8438, 843803 (2012) https://doi.org/10.1117/12.921590

KEYWORDS: Glasses, Solar cells, Cadmium sulfide, External quantum efficiency, Samarium, Barium, Quantum efficiency, Doping, Oxides, Luminescence

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Proceedings Article | 2 May 2012 Paper

Optical characterization of TCO films on borate glasses for high efficiency solar cells

Franziska Steudel, Paul-Tiberiu Miclea, Nico Teuscher, Andreas Heilmann, Stefan Schweizer

Proceedings Volume 8438, 843819 (2012) https://doi.org/10.1117/12.922013

KEYWORDS: Glasses, Sputter deposition, Transparent conductors, Optical simulations, Oxygen, Transmittance, Protactinium, Oxides, Zinc oxide, Thin films

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Proceedings Article | 13 September 2011 Paper

Investigations on crack development and crack growth in embedded solar cells

M. Sander, S. Dietrich, M. Pander, S. Schweizer, M. Ebert, J. Bagdahn

Proceedings Volume 8112, 811209 (2011) https://doi.org/10.1117/12.893662

KEYWORDS: Solar cells, Glasses, Electroluminescence, Numerical simulations, Silicon, Polymers, Manufacturing, Statistical analysis, Crystalline solar cells, Crystals

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Proceedings Article | 12 September 2011 Paper

Periodic silicon nanostructures for spectroscopic microsensors

Ralf Wehrspohn, Benjamin Gesemann, Daniel Pergande, Torsten Geppert, Stefan Schweizer, Susanne Moretton, Armin Lambrecht

Proceedings Volume 8095, 809508 (2011) https://doi.org/10.1117/12.904994

KEYWORDS: Silicon, Absorption, Gas sensors, Etching, Photonic crystals, Ionization, Sensors, Platinum, Infrared radiation, Carbon dioxide

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Proceedings Article | 24 August 2010 Paper

Advances in up- and down-converted fluorescence for high efficiency solar cells using rare-earth doped fluorozirconate-based glasses and glass ceramics

Christian Paßlick, Bastian Henke, István Császár, Bernd Ahrens, Paul-T. Miclea, Jacqueline Johnson, Stefan Schweizer

Proceedings Volume 7772, 77720A (2010) https://doi.org/10.1117/12.860196

KEYWORDS: Glasses, Solar cells, Luminescence, Annealing, Ceramics, Absorption, Nanocrystals, Silicon solar cells, Ions, Ultraviolet radiation

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Proceedings Article | 19 August 2010 Paper

Characterization of PV modules by combining results of mechanical and electrical analysis methods

Martin Sander, Bastian Henke, Hannes Schwarz, Sascha Dietrich, Stefan Schweizer, Matthias Ebert, Jörg Bagdahn

Proceedings Volume 7773, 777308 (2010) https://doi.org/10.1117/12.860814

KEYWORDS: Solar cells, Glasses, Electroluminescence, Temperature metrology, Polymers, Thermography, Crystals, Reliability, Manufacturing, Resistance

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Proceedings Article | 18 May 2010 Paper

Photon down-conversion in Terbium(III)-doped thin dielectric films and fluorozirconate glasses for thin film solar cells

K. Baumgartner, B. Ahrens, O. Angelov, M. Sendova-Vassileva, D. Dimova-Malinovska, B. Holländer, S. Schweizer, R. Carius

Proceedings Volume 7725, 77250T (2010) https://doi.org/10.1117/12.853939

KEYWORDS: Terbium, Thin films, Ions, Glasses, Absorption, Annealing, Silica, Thin film solar cells, Luminescence, Silicon

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Proceedings Article | 18 May 2010 Paper

Spectral down-conversion in Sm-doped borate glasses for photovoltaic applications

Marcel Dyrba, Paul Miclea, Stefan Schweizer

Proceedings Volume 7725, 77251D (2010) https://doi.org/10.1117/12.853942

KEYWORDS: Glasses, Luminescence, Lead, Absorption, Sodium, Lithium, Barium, Ions, Solar cells, Silicon solar cells

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Proceedings Article | 18 May 2010 Paper

Progress on up- and down-converted fluorescence in rare-doped fluorozirconate-based glass ceramics for high efficiency solar cells

Stefan Schweizer, Bastian Henke, Bernd Ahrens, Christian Paßlick, Paul Miclea, Johannes Wenzel, Eduard Reisacher, Wulf Pfeiffer, Jacqueline Johnson

Proceedings Volume 7725, 77250X (2010) https://doi.org/10.1117/12.853943

KEYWORDS: Glasses, Ceramics, Luminescence, Solar cells, Ultraviolet radiation, Nanocrystals, Absorption, Ions, Annealing, Doping

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Proceedings Article | 23 March 2010 Paper

Scanning translucent glass-ceramic x-ray storage phosphors

A. Lubinsky, J. Johnson, S. Schweizer, J. K. Weber, R. Nishikawa, P. Domenicali, S. Fantone

Proceedings Volume 7622, 76223W (2010) https://doi.org/10.1117/12.843346

KEYWORDS: Translucency, Imaging systems, Modulation transfer functions, Glasses, Mirrors, X-rays, Light scattering, Chromium, Scanners, Ceramics

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Proceedings Article | 2 September 2009 Paper

Infiltration of individual pores in macroporous silicon photonic crystals

Peter Nolte, Daniel Pergande, Stefan Schweizer, Markus Geuss, Roland Salzer, Brian Makowski, Martin Steinhart, Ralf Wehrspohn, Christoph Weder

Proceedings Volume 7393, 73930S (2009) https://doi.org/10.1117/12.824862

KEYWORDS: Gold, Photonic crystals, Polymers, Silicon, Ion beams, Silicon photonics, Crystals, Polishing, Fabrication, Nonlinear optics

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Proceedings Article | 20 August 2009 Paper

Upconverted fluorescence in Er-doped ZBLAN glasses for high efficiency solar cells

Bastian Henke, Bernd Ahrens, Jacqueline Johnson, Paul Miclea, Stefan Schweizer

Proceedings Volume 7411, 74110E (2009) https://doi.org/10.1117/12.825275

KEYWORDS: Glasses, External quantum efficiency, Luminescence, Solar cells, Upconversion, Photons, Near infrared, Silicon solar cells, Doping, Solar energy

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Proceedings Article | 5 May 2008 Paper

Enhanced up-converted fluorescence in fluorozirconate based glass ceramics for high efficiency solar cells

Bernd Ahrens, Bastian Henke, Paul Miclea, Jacqueline Johnson, Stefan Schweizer

Proceedings Volume 7002, 700206 (2008) https://doi.org/10.1117/12.779271

KEYWORDS: Luminescence, Glasses, Ceramics, Ions, Neodymium, Photons, Infrared radiation, Solar cells, Annealing, Solar energy

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Proceedings Article | 21 April 2008 Paper

Thermal emission properties of 2D and 3D silicon photonic crystals

Benjamin Gesemann, Stefan Schweizer, Ralf Wehrspohn

Proceedings Volume 6989, 69890T (2008) https://doi.org/10.1117/12.781028

KEYWORDS: Photonic crystals, Crystals, Silicon, Silicon photonics, 3D metrology, Oxides, Modulation, Tungsten, Temperature metrology, Numerical simulations

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Proceedings Article | 19 March 2007 Paper

Fluorozirconate-based glass-ceramic storage phosphors for digital mammography

Stefan Schweizer, Anthony Lubinsky, Jacqueline Johnson

Proceedings Volume 6510, 651046 (2007) https://doi.org/10.1117/12.708758

KEYWORDS: X-rays, Chromium, Modulation transfer functions, Glasses, Mammography, Imaging systems, Ceramics, Absorption, Quantum efficiency, Chlorine

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Proceedings Article | 3 February 2007 Paper

Miniature infrared gas sensors using photonic crystals

A. Lambrecht, S. Hartwig, S. Schweizer, R. Wehrspohn

Proceedings Volume 6480, 64800D (2007) https://doi.org/10.1117/12.700792

KEYWORDS: Gas sensors, Photonic crystals, Silicon, Infrared radiation, Carbon monoxide, Sensors, Absorption, Etching, Infrared sensors, Modulation

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Proceedings Article | 14 April 2006 Paper

Glass based fluorescence reference materials used for optical and biophotonic applications

A. Engel, C. Ottermann, U. Resch-Genger, K. Hoffmann, S. Schweizer, J. Selling, J.-M. Spaeth, V. Rupertus

Proceedings Volume 6191, 619110 (2006) https://doi.org/10.1117/12.663627

KEYWORDS: Glasses, Luminescence, Crystals, Absorption, Ceramics, Ultraviolet radiation, Transition metals, Biophotonic applications, Calibration, Manganese

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Proceedings Article | 2 March 2006 Paper

Transparent BaCl₂:Eu²⁺ glass-ceramic scintillator

Gang Chen, Jacqueline Johnson, Stefan Schweizer, John Woodford, Peter Newman, Douglas MacFarlane

Proceedings Volume 6142, 61422X (2006) https://doi.org/10.1117/12.654265

KEYWORDS: Glasses, Scintillators, Europium, Crystals, Ceramics, X-rays, X-ray imaging, Scintillation, Modulation transfer functions, ZBLAN

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Proceedings Article | 2 March 2006 Paper

Energy-dependent scintillation intensity of fluorozirconate-based glass-ceramic x-ray detectors

Stefan Schweizer, Bastian Henke, Stephanie Köneke, Jacqueline Johnson, Gang Chen, John Woodford

Proceedings Volume 6142, 61422Y (2006) https://doi.org/10.1117/12.653769

KEYWORDS: Glasses, Scintillation, X-rays, Ceramics, Europium, Crystals, Nanocrystals, X-ray detectors, Particles, Mass attenuation coefficient

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Proceedings Article | 1 October 2005 Paper

Nonlinear femtosecond pulse tuning of 2-D photonic crystals

Henry van Driel, H. Tan, S. Schweizer, R. Wehrspohn

Proceedings Volume 5971, 59710J (2005) https://doi.org/10.1117/12.628670

KEYWORDS: Photonic crystals, Reflectivity, Kerr effect, Silicon, Picosecond phenomena, Femtosecond phenomena, Crystals, Dielectrics, Refractive index, Laser beam diagnostics

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Proceedings Article | 13 September 2005 Paper

Nonlinear optical tuning in a 2-D silicon photonic crystal

Stefan Schweizer, Ralf Wehrspohn, Hong-Wee Tan, Henry van Driel

Proceedings Volume 5926, 59260C (2005) https://doi.org/10.1117/12.616985

KEYWORDS: Reflectivity, Photonic crystals, Crystals, Silicon, Refractive index, Absorption, Laser beam diagnostics, Silicon photonics, Picosecond phenomena, Kerr effect

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Proceedings Article | 26 August 2005 Paper

Surface enhanced Raman spectroscopy on monodisperse silver and nickel nanowires

P.-T. Miclea, G. Sauer, G. Brehm, S. Schneider, H. Graener, G. Seifert, K. Nielsch, J. Choi, P. Goring, U. Gosele, S. Schweizer, R. Wehrspohn

Proceedings Volume 5927, 59270O (2005) https://doi.org/10.1117/12.616315

KEYWORDS: Metals, Nickel, Surface enhanced Raman spectroscopy, Silver, Molecules, Mie scattering, Particles, Dielectrics, Raman spectroscopy, Nanowires

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Proceedings Article | 23 May 2005 Paper

Photonic crystal gas sensors

R. Wehrspohn, T. Geppert, S. Schweizer, A. Rhein, D. Pergande, T. Beyer, Armin Lambrecht

Proceedings Volume 5855, (2005) https://doi.org/10.1117/12.623381

KEYWORDS: Photonic crystals, Gas sensors, Sensors, Silicon, Absorption, Refractive index, Gases, Dielectrics, Spectroscopy, Semiconductors

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Proceedings Article | 20 April 2005 Paper

ZBLAN-based x-ray storage phosphors and scintillators for digital x-ray imaging

Gang Chen, Jacqueline Johnson, Richard Weber, Stefan Schweizer, Douglas MacFarlane, John Woodford, Francesco De Carlo

Proceedings Volume 5745, (2005) https://doi.org/10.1117/12.617082

KEYWORDS: X-rays, Glasses, Crystals, X-ray imaging, ZBLAN, Ceramics, Europium, Scintillators, Image resolution, Image storage

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Proceedings Article | 14 October 2004 Paper

Photonic crystal gas sensors

Torsten Geppert, Stefan Schweizer, J. Schilling, Cecile Jamois, A. V. Rhein, D. Pergande, Regine Glatthaar, P. Hahn, A. Feisst, Armin Lambrecht, Ralf Wehrspohn

Proceedings Volume 5511, (2004) https://doi.org/10.1117/12.561724

KEYWORDS: Gas sensors, Photonic crystals, Silicon, Absorption, Dielectrics, Sensors, Refractive index, Gases, Distortion, Chemical species

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Proceedings Article | 14 October 2004 Paper

Tuning 2D photonic crystals

Henry van Driel, Stephen Leonard, Hong-Wee Tan, A. Birner, J. Schilling, Stefan Schweizer, Ralf Wehrspohn, Ulrich Gosele

Proceedings Volume 5511, (2004) https://doi.org/10.1117/12.559914

KEYWORDS: Photonic crystals, Liquid crystals, Crystals, Silicon, Reflectivity, Dielectrics, Silicon photonics, Optical properties, Kerr effect, Refractive index

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Proceedings Article | 25 March 2004 Paper

Periodically arranged point defects in a 2D photonic crystal: the photonic analogue to a doped semiconductor

Stefan Richter, Stefan Schweizer, Reinald Hillebrand, Cecile Jamois, Ralf Wehrspohn, Margit Zacharias, Ulrich Goesele

Proceedings Volume 5277, (2004) https://doi.org/10.1117/12.522063

KEYWORDS: Photonic crystals, Crystals, Resonators, Reflection, Semiconductors, Silicon, Dielectrics, Diffraction, Reflectivity, Scanning electron microscopy

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Showing 5 of 33 publications

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