Synthesis and crystal growth of rare earth halides
IR to VIS upconversion
Rare earth phosphors and scintillators
Magnetic structures

L. Keller, A. Furrer, P. Fischer, P. Allenspach, K. Krämer, H. U. Güdel A. Dönni, and T. Suzuki
Magnetic phase transitions and crystal-field splitting in K₂UX₅ (X=Cl, Br, I)
Phys.Rev.B. 51, 2881-2890 (1995)           

Toni Riedener, Karl Krämer and Hans U. Güdel
Upconversion Luminescence in Er³⁺-Doped RbGd₂Cl₇ and RbGd₂Br₇
Inorg.Chem. 34, 2745-2752 (1995)           

M. Pollnau, W. Lüthy, H. P. Weber, K. Krämer, H. U. Güdel and R. A. McFarlane
Excited-State Absorption in Er:BaY₂F₈, and Cs₃Er₂Br₉ and Comparison to Er:LiYF₄
Appl.Phys.B. 62, 339-344 (1996)           

Karl Krämer, Harald Romstedt, Hans-Ulrich Güdel, Peter Fischer, Andrej Murasik and Maria Teresa Fernandez-Diaz
3-D Magnetic Structure of ErF₃
Eur.J.Solid State Inorg.Chem. 33, 273-283 (1996)           

M. Pollnau, W. Lüthy, H. P. Weber, K. Krämer, H. U. Güdel and R. A. McFarlane
Excited-State Dynamics in the Low-Phonon Materials Er³⁺: BaY₂F₈ and Cs₃Er₂Br₉
OSA Topical Meeting on "Advanced Solid State Lasers" , S. Payne and C. Pollock (editors), Vol. 1, 474-477 (1996)           

H. P. Andres, K. Krämer and H.-U. Güdel
Optical absorption and luminescence spectroscopy of U³⁺ in K₂LaX₅ (X=Cl,Br,I)
Phys.Rev.B. 54, 3830 (1996)           

J. van 't Spijker, P. Dorenbos, J. de Haas, C. van Eijk, H. U. Güdel and K. Krämer
Scintillation Mechanism of K₂LaCl₅ doped with Ce
Proceedings Int.Conf.on Inorg.Scintillators, SCINT95 411-414 (1996)           

Karl W. Krämer, Hans U. Güdel and Robert N. Schwartz
Infrared-to-visible upconversion in LaCl₃: 1% Er³⁺: Energy-level and line-strength calculations
Phys. Rev. B 56, 13830-13840 (1997)      Abstract                 

P. Dorenbos, J. C. van't Spijker, O. W. V. Frijns, C. W. E. van Eijk, K. Krämer, H. U. Güdel and A. Ellens
Scintillation properties of RbGd₂Br₇: Ce³⁺ crystals; fast, efficient, and high density scintillators
Nucl. Instr. Methods Phys. Res. B 132, 728-731 (1997)      Abstract                 

Karl W. Krämer, Hans U. Güdel and Robert N. Schwartz
NIR to VIS upconversion in LaCl₃: 1% Er³⁺
One- and two-color excitations around 1000 and 800 nm
J. Alloys Comp. 275-277, 191-195 (1998)      Abstract                 

Ard Ellens, Karl Krämer and Hans U. Güdel
Comparison of the electron-phonon coupling strength of U³⁺ and Nd³⁺ in K₂LaCl₅
J. Lumin. 76-77, 548-550 (1998)      Abstract                 

N. Cavadini, W. Henggeler, A. Furrer, H.-U. Güdel, K. Krämer and H. Mutka
Magnetic excitations in the quantum spin system KCuCl₃
Eur. Phys. J. B 7, 519-522 (1999)      Abstract                 

K. W. Krämer, H. U. Güdel, B. Roessli, P. Fischer, A. Dönni, N. Wada, F. Fauth, M. T. Fernandez-Diaz and T. Hauss
Noncollinear two- and three-dimensional magnetic ordering in the honeycomb lattices of ErX₃ (X = Cl,Br,I)
Phys. Rev. B 60, 3724-3727 (1999)      Abstract                 

W. Henggeler, N. Cavadini, A. Furrer, H. U. Güdel, K. Krämer and H. Mutka
Magnetic excitations in the quantum spin system KCuCl₃
ILL Annual Report 98, 22-23 (1999)      Abstract                 

C. M. Combes, P. Dorenbos, C. W. E. van Eijk, K. W. Krämer and H. U. Güdel
Optical and scintillation properties of pure and Ce³⁺-doped Cs₂LiYCl₆ and Li₃YCl₆:Ce³⁺ crystals
J. Lumin. 82, 299-305 (1999)      Abstract                 

O. Guillot-Noel, J. C. van't Spijker, J. T. M. de Haas, P. Dorenbos, C. W. E. van Eijk, K. W. Krämer and H. U. Güdel
Scintillator Properties of RbGd₂Br₇:Ce. Advantages and Limitations.
IEEE Trans. Nucl. Sci. 46 (5), (1999)      Abstract                 

O. Guillot-Noel, J. T. M. de Haas, P. Dorenbos, C. W. E. van Eijk, K. Krämer and H. U. Güdel
Optical and scintillation properties of cerium-doped LaCl₃, LuBr₃ and LuCl₃
J. Lumin. 85, 21-35 (1999)      Abstract                 

J. C. van 't Spijker, P. Dorenbos, C. W. E. van Eijk, K. Krämer and H. U. Güdel
Scintillation and luminescence properties of Ce³⁺ doped K₂LaCl₅
J. Lumin. 85, 1-10 (1999)      Abstract                 

N. Cavadini, W. Henggeler, A. Furrer, H.-U. Güdel, K. Krämer and H. Mutka
Magnetic excitations and spin gap in KCuCl₃
Physica B 540, 276-278 (2000)      Abstract                 

K. W. Krämer, H. U. Güdel, B. Roessli, P. Fischer, A. Dönni, N. Wada, F. Fauth, M. T. Fernandez-Diaz and T. Hauss
Magnetic ordering in the erbium honeycomb lattices of ErX₃ (X=Cl, Br ,I)
Physica B 276-278, 674-675 (2000)      Abstract                 

D. Schaniel, P. Allenspach, A. Furrer, K. Krämer and H. U. Güdel
Dimer splitting of Er³⁺ in Cs₃Er₂X₉ (X = Cl, Br): mystery solved
Physica B 276-278, 690-691 (2000)      Abstract                 

N. Cavadini, G. Heigold, W. Henggeler, A. Furrer, H.-U. Güdel, K. Krämer and H. Mutka
Quantum magnetic interactions in S=1/2 KCuCl₃
J. Phys.: Condens. Matter 12, 5463-5472 (2000)      Abstract                 

D. Andreica, N. Cavadini, H. U. Güdel, F. N. Gygax, K. Krämer, M. Pinkpank and A. Schenck
Muon-induced break up of spin-singlet pairs in the double-chain compound KCuCl₃
Physica B 289-290, 176-180 (2000)      Abstract                 

E. V. D. van Loef, P. Dorenbos and C. W. E. van Eijk, K. Krämer and H. U. Güdel
High-energy-resolution scintillator: Ce³⁺ activated LaCl₃
Appl. Phys. Lett. 77, 1467-1468 (2000)      Abstract                 

R. Burlot-Loison, M. Pollnau, K. Krämer, P. Egger, J. Hulliger and H. U. Güdel
Laser-relevant spectroscopy and upconversion mechanisms of Er³⁺ in Ba₂YCl₇ pumped at 800 nm
J. Opt. Soc. Am. B 17, 2055-2067 (2000)      Abstract                 

K. W. Krämer, H. U. Güdel, P. Fischer, F. Fauth, M. T. Fernandez-Diaz and T. Hauss
Triangular antiferromagnetic order in the honeycomb layer lattice of ErCl₃
Eur. Phys. J. B 18, 39-47 (2000)      Abstract                 

N. Cavadini, Ch. Rüegg, W. Henggeler, A. Furrer, H.-U. Güdel, K. Krämer and H. Mutka
Temperature renormalization of the magnetic excitations in S=1/2 KCuCl₃
Eur. Phys. J. B 18, 565-571 (2000)      Abstract                 

N. Cavadini, W. Henggeler, A. Furrer, K. Krämer, H. U. Güdel, H. Mutka, A. Wildes and P. Vorderwisch
Triplet Excitations in a Family of S=1/2 Unconventional Antiferromagnets
in "Neutron Scattering in Novel Materials", A. Furrer (ed.)
World Scientific, Singapore, 237-251 (2000)      Abstract           

P. Dorenbos, C. W. E. van Eijk, H. U. Güdel, K. W. Krämer and E. V. D. van Loef
Ceriumhoudend anorganisch scintillatormateriaal
Dutch patent no. 1014401, 17 february 2000      Abstract                 

S. Heer, M. Wermuth, K. Krämer and H. U. Güdel
Upconversion excitation of Cr^{3+ 2}E emission in Y₃Ga₅O₁₂ codoped with Cr³⁺ and Yb³⁺
Chem. Phys. Lett. 334, 293-297 (2001)      Abstract                 

E. V. D. van Loef, P. Dorenbos, C. W. E. van Eijk, K. W. Krämer and H. U. Güdel
Optical and scintillation properties of pure and Ce³⁺ doped GdBr₃
Optics Communications 189, 297-304 (2001)      Abstract                 

N. Cavadini, G. Heigold, W. Henggeler, A. Furrer, H.-U. Güdel, K. Krämer and H. Mutka
Magnetic excitations in the quantum spin system TlCuCl₃
Phys. Rev. B 63, 172414/1-4 (2001)      Abstract                 

D. Schaniel, P. Allenspach, A. Furrer, K. Krämer and H. U. Güdel
Dimer Splitting of Er³⁺ in Cs₃Er₂Br₉
J. Alloys Comp. 323-324, 481-485 (2001)      Abstract                 

P. Dorenbos, C. W. E. von Eijk, H. U. Güdel, K. W. Krämer and E. V. D. van Loef
Scintillator crystals, method for making same, use thereof
Organisation Mondiale de la Propriété Intellectuelle,
Int. patent number WO 01/60944 A2, 23.08.2001      Abstract                 

P. Dorenbos, C. W. E. von Eijk, H. U. Güdel, K. W. Krämer and E. V. D. van Loef
Scintillator crystals, method for making same, use thereof
Organisation Mondiale de la Propriété Intellectuelle,
Int. patent number WO 01/60945 A2, 23.08.2001      Abstract                 

Karl W. Krämer, Ralph Schenker, Jürg Hauser, Høgni Weihe, Hans U. Güdel and Hans-Beat Bürgi
Crystal Structures of (Et₄N)₃M₂F₉ (M = V, Cr, Fe) determined by X-Ray Single-Crystal and Powder Diffraction: A New Structure Type for A₃M₂X₉ Compounds
Z. Anorg. Allg. Chem. 627, 2511-2516 (2001)      Abstract                 

E. V. D. van Loef, P. Dorenbos, C. W. E. van Eijk, K. Krämer and H. U. Güdel
Scintillation Properties of LaCl₃:Ce³⁺ Crystals: 
Fast, Efficient and High-Energy Resolution Scintillators
IEEE Trans. Nucl. Sci. 48, 341-345 (2001)      Abstract                 

E. V. D. van Loef, P. Dorenbos, C. W. E. van Eijk, K. Krämer and H. U. Güdel
High-energy-resolution scintillator: Ce³⁺ activated LaBr₃
Appl. Phys. Lett. 79, 1573-1575 (2001)      Abstract                 

C. W. E. van Eijk, P. Dorenbos, E. V. D. van Loef, K. Krämer and H. U. Güdel
Energy resolution of some new inorganic-scintillator gamma-ray detectors
Rad. Meas. 33, 521-525 (2001)      Abstract                 

N. Cavadini, W. Henggeler, A. Furrer, K. Krämer, H. U. Güdel, H. Mutka, A. Wildes and P. Vorderwisch
Quantum magnetic phase transition: a top-down approach
ILL Annual Report 2000, 12-13 (2001)      Abstract                 

N. Cavadini, A. Furrer, H.-U. Güdel, K. Krämer, H. Mutka and A. Wildes
Polarization Study of the Singlet-Triplet Modes in a Quantum Spin System
Proc. ILL millennium symposium, 145-146 (2001)      Abstract                 

Oliver S. Wenger, Claudia Wickleder, Karl W. Krämer and Hans U. Güdel
Upconversion in a divalent rare earth ion: optical absorption and luminescence spectroscopy of Tm²⁺ doped SrCl₂
J. Lumin. 94-95, 101-105 (2001)      Abstract                 

S. Heer, M. Wermuth, K. Krämer, D. Ehrentraut and H. U. Güdel
Up-conversion excitation of sharp Cr^{3+ 2}E emission in YGG and YAG codoped with Cr³⁺ and Yb³⁺
J. Lumin. 94-95, 337-341 (2001)      Abstract                 

N. Cavadini, Ch. Rüegg, A. Furrer, H. U. Güdel, K. Krämer, H. Mutka and P. Vorderwisch
Triplet excitations in low-H_c spin gap systems KCuCl₃ and TlCuCl₃: An inelastic neutron scattering study
Phys. Rev. B 65, 132415/1-4 (2002)      Abstract                 

S. Heer, M. Wermuth, K. Krämer and H. U. Güdel
Sharp ²E upconversion luminescence of Cr³⁺ in Y₃Ga₅O₁₂ codoped with Cr³⁺ and Yb³⁺
Phys. Rev. B 65, 125112/1-10 (2002)      Abstract                 

C. P. Allier, E. V. D. van Loef, P. Dorenbos, R. W. Hollander, C. W. E. van Eijk, K. W. Krämer and H. U. Güdel
Readout of a LaCl₃(Ce³⁺) scintillation crystal with a large area avalanche photodiode
Nucl. Instr. and Methods Phys. Res. A 485, 547-550 (2002)      Abstract                 

E. V. D. van Loef, P. Dorenbos, C. W. E. van Eijk, K. W. Krämer and H. U. Güdel
Scintillation properties of LaBr₃:Ce³⁺ crystals: fast, efficient and high-energy-resolution scintillators
Nucl. Instr. and Methods Phys. Res. A 486, 254-258 (2002)      Abstract                 

E. V. D. van Loef, P. Dorenbos, C. W. E. van Eijk, K. W. Krämer and Hans U. Güdel
Scintillation and spectroscopy of the pure and Ce³⁺-doped elpasolites: Cs₂LiYX₆ (X = Cl, Br)
J. Phys.: Condens. Matter 14, 8481-8496 (2002)      Abstract                 

N. Cavadini, Ch. Rüegg, A. Furrer, H. U. Güdel, K. Krämer, H. Mutka, A. Wildes, K. Habicht and P. Vorderwisch
Triplet modes in a quantum spin liquid across the critical field
Int. J. Mod. Phys. B 16, 3302-3305 (2002)      Abstract                 

K. W. Krämer, H. U. Güdel, P. Fischer and L. Keller
Magnetic order in CeI₂
Appl. Phys. A 74, S595-S597 (2002)      Abstract                 

Ch. Rüegg, N. Cavadini, A. Furrer, K. Krämer, H. U. Güdel, P. Vorderwisch and H. Mutka
Spin dynamics in the high-field phase of quantum-critical S = 1/2 TlCuCl₃
Appl. Phys. A 74, S840-S842 (2002)      Abstract                 

U. Rogulis, S. Schweizer, J.-M. Spaeth, E. V. D. van Loef, P. Dorenbos, C. W. E. van Eijk, K. Krämer and H. U. Güdel
Magnetic Resonance Investigations of LaCl₃:Ce³⁺ Scintillators
Radiation Effects and Defects in Solids 157, 951-955 (2002)      Abstract                 

G. Mackay Salley, Oliver S. Wenger, Karl W. Krämer and Hans U. Güdel
Inorganic solid state optical materials: Major recent advances
Current Opinion in Solid State and Materials Science 6, 487-493 (2002)      Abstract                 

Pascal Gerner, Karl Krämer and Hans U. Güdel
Broad-band Cr⁵⁺-sensitized Er³⁺ luminescence in YVO₄
J. Lumin. 102-103, 112-118 (2003)      Abstract                 

Ch. Rüegg, N. Cavadini, A. Furrer, H.-U. Güdel, K. Krämer, H. Mutka, A. Wildes, K. Habicht and P. Vorderwisch
Bose–Einstein condensation of the triplet states in the magnetic insulator TlCuCl₃
Nature 423, 62-65 (2003)      Abstract                 

E. V. D. van Loef, P. Dorenbos, C. W. E. van Eijk, K. W. Krämer and H. U. Güdel
Properties and mechanism of scintillation in LuCl₃:Ce³⁺ and LuBr₃:Ce³⁺ crystals
Nucl. Instr. and Methods Phys. Res. A 496, 138-145 (2003)      Abstract                 

N. Cavadini, D. Andreica, F. N. Gygax, A. Schenck, K. Krämer, H.-U. Güdel, H. Mutka and A. Wildes
Local spin susceptibility in KCuCl₃
Physica B 335, 37-40 (2003)      Abstract                 

E. V. D. van Loef, P. Dorenbos, C. W. E. van Eijk, K. W. Krämer and H. U. Güdel
Influence of the anion on the spectroscopy and scintillation mechanism in pure and Ce³⁺-doped K₂LaX₅ and LaX₃ (X = Cl, Br, I)
Phys. Rev. B 68, 045108/1-9 (2003)      Abstract                 

P. Dorenbos, E. V. D. van Loef, C. W. E. van Eijk, K. W. Krämer and H. U. Güdel
Anomalous 10-ns emission in Ce³⁺-doped Cs₃LuCl₆
Phys. Rev. B 68, 125108/1-6 (2003)      Abstract                 

A. Shalav, B. S. Richards, T. Trupke, R. P. Corkish, K. W. Krämer, H. U. Güdel and M. A. Green
The Application of Up-Converting Phosphors for Increased Solar Cell Conversion Efficiencies
Proc. 3^rd World Conf. Photovoltaic Energy Conversion, Osaka, May 12-16, 2003, p. 248-250      Abstract                 

Christine Reinhard, Karl Krämer, Daniel A. Biner and Hans U. Güdel
Cooperative radiative and nonradiative effects in K₂NaScF₆ codoped with V³⁺ and Er³⁺
J. Chem. Phys. 120, 3374-3380 (2004)      Abstract                 

A. Bessière, P. Dorenbos, C. W. E. van Eijk, L. Pidol, K. W. Krämer and Hans U. Güdel
Spectroscopy and anomalous emission of Ce doped elpasolite Cs₂LiYCl₆
J. Phys.: Condens. Matter, 16, 1887-1897 (2004)      Abstract                 

Karl W. Krämer, Daniel Biner, Gabriela Frei, Hans U. Güdel, Markus P. Hehlen and Stefan R. Lüthi
Hexagonal Sodium Yttrium Fluoride Based Green and Blue Emitting Upconversion Phosphors
Chem. Mater. 16, 1244-1251 (2004)      Abstract                 

Christine Reinhard, Karl Krämer, Daniel A. Biner and Hans-Ulrich Güdel
V³⁺ sensitized upconversion in Cs₂NaScCl₆:Pr³⁺;V³⁺ and K₂NaScF₆:Er³⁺;V³⁺
J. Alloys Comp. 134, 133-136 (2004)      Abstract                 

Ch. Rüegg, N. Cavadini, A. Furrer, K. Krämer, H.-U. Güdel, P. Vorderwisch, K. Habicht, H. Mutka and A. Wildes
Spin dynamics in the BEC phase of the S=1/2 quantum spin system TlCuCl₃
J. Magn. Magn. Mater. 272-276, 195-196 (2004)      Abstract                 

Th. Strässle, F. Juranyi, M. Schneider, S. Janssen, A. Furrer, K. W. Krämer and H. U. Güdel
Origin of Higher Order Magnetic Exchange: Evidence for Local Dimer Exchange Striction in CsMn_0.28Mg_0.72Br₃ Probed by Inelastic Neutron Scattering
Phys. Rev. Lett. 92, 257202/1-4 (2004)      Abstract                 

Ch. Rüegg, M. Oettli, J. Schefer, O. Zaharko, A. Furrer, H. Tanaka, K. W. Krämer, H.-U. Güdel, P. Vorderwisch, K. Habicht, T. Polinski and M. Meissner
Neutron Scattering Study of the Field-Dependent Ground State and the Spin Dynamics in Spin-One-Half NH₄CuCl₃
Phys. Rev. Lett. 93, 037207/1-4 (2004)      Abstract                 

A. Bessière, P. Dorenbos, C. W. E. van Eijk, K. Krämer and H. U. Güdel
New thermal neutron scintillators: Cs₂LiYCl₆ : Ce³⁺ and Cs₂LiYBr₆ : Ce³⁺
IEEE Trans. Nucl. Sci. 51, 2970-2972 (2004)      Abstract                 

Ch. Rüegg, A. Furrer, D. Sheptyakov, Th. Strässle, K. W. Krämer, H.-U. Güdel and L. Mélési
Pressure-Induced Quantum Phase Transition in the Spin-Liquid TlCuCl₃
Phys. Rev. Lett. 93, 257201/1-4 (2004)      Abstract                 

P. Dorenbos, C. W. E. van Eijk, H. U. Güdel, E. V. D. van Loef and K. W. Krämer
Cristaux scintillateurs du type iodure de terre rare
French patent no. FR 2855830-A1, 10.12.2004      Abstract                 

A. Bessiere, P. Dorenbos, C. W. E. van Eijk, K. W. Krämer, H. U. Güdel, C. de Mello Donega and A. Meijerink
Luminescence and scintillation properties of the small band gap compound LaI₃:Ce³⁺
Nucl. Instr. Methods Phys. Res. A 537, 22-26 (2005)      Abstract                 

E. V. D. van Loef, P. Dorenbos, C. W. E. van Eijk, K. W. Krämer and H. U. Güdel
Scintillation properties of K₂LaX₅:Ce³⁺ (X=Cl, Br, I)
Nucl. Instr. Methods Phys. Res. A 537, 232-236 (2005)      Abstract                 

A. Bessiere, P. Dorenbos, C. W. E. van Eijk, K. W. Krämer and H. U. Güdel
Luminescence and scintillation properties of Cs₂LiYCl₆:Ce³⁺ for g and neutron detection
Nucl. Instr. Methods Phys. Res. A 537, 242-246 (2005)      Abstract                 

A. Shalav, B. S. Richards, T. Trupke, K. W. Krämer and H. U. Güdel
Application of NaYF₄:Er³⁺ up-converting phosphors for enhanced near-infrared silicon solar cell response
Appl. Phys. Lett. 86, 013505/1-3 (2005)      Abstract                 

J. F. Suyver, A. Aebischer, D. Biner, P. Gerner, J. Grimm, S. Heer, K. W. Krämer, C. Reinhard and H. U. Güdel
Novel materials doped with trivalent lanthanides and transition metal ions showing near-infrared to visible photon upconversion
Opt. Mater. 27, 1111-1130 (2005)      Abstract                 

Dominik Schaniel, Theo Woike, Bernard Delley, Colette Boskovic, Daniel Biner, Karl W. Krämer and Hans-Ueli Güdel
Long-lived light-induced metastable states in trans-[Ru(NH₃)₄(H₂O)NO]Cl₃·H₂O and related compounds
Phys. Chem. Chem. Phys. 7, 1164-1170 (2005)      Abstract                 

Annina Aebischer, Stephan Heer, Daniel Biner, Karl Krämer, Markus Haase and Hans U. Güdel
Visible light emission upon near-infrared excitation in a transparent solution of nanocrystalline b-NaGdF₄: Yb³⁺, Er³⁺
Chem. Phys. Lett. 407, 124-128 (2005)      Abstract                 

J. F. Suyver, J. Grimm, K. W. Krämer and H. U. Güdel
Highly efficient near-infrared to visible up-conversion process in NaYF₄:Er³⁺,Yb³⁺
J. Lumin. 114, 53-59 (2005)      Abstract                 

Karl Wilhelm Krämer, Hans-Ulrich Güdel, Aurélie Bessière, Pieter Dorenbos and Carel Wilhelm Eduard van Eijk
High light yield thermal neutron scintillators
European Patent Office,
European patent number EP 1 553 430 A1, 13.07.2005      Abstract                 

Hans-Benjamin Braun, Jiri Kulda, Bertrand Roessli, Dirk Visser, Karl W. Krämer, Hans-Ulrich Güdel and Peter Böni
Emergence of soliton chirality in a quantum antiferromagnet
Nature Phys. 1, 159-163 (2005)      Abstract                       

M. D. Birowosuto, P. Dorenbos, C. W.E. van Eijk, K. W. Krämer and H. U. Güdel
Scintillation Properties of LuI₃:Ce³⁺-High Light Yield Scintillators
IEEE Trans. Nucl. Sci. 52, 1114-1118 (2005)      Abstract                 

Avi Shalav, Bryce S. Richards, Karl Krämer and H. U. Güdel
Improvements of an up-conversion NaYF₄:Er³⁺ phosphor/silicon solar cell system for an enhanced response in the near-infrared
in "Conference Record of the 31st IEEE Photovoltaic Specialists Conference", Florida, January 2005
Institute of Electrical and Electronics Engineers, ISBN 0-7803-8707-4, 114-117 (2005)      Abstract                 

Ch. Rüegg, B. Normand, M. Matsumoto, Ch. Niedermayer, A. Furrer, K. W. Krämer, H.-U. Güdel, Ph. Bourges, Y. Sidis and H. Mutka
Quantum Statistics of Interacting Dimer Spin Systems
Phys. Rev. Lett. 95, 267201/1-4 (2005)      Abstract                 

J. F. Suyver, J. Grimm, M. K. van Veen, D. Biner, K. W. Krämer and H. U. Güdel
Upconversion spectroscopy and properties of NaYF₄ doped with Er³⁺, Tm³⁺ and/or Yb³⁺
J. Lumin. 117, 1-12 (2006)      Abstract                 

P. Dorenbos, E. V. D. van Loef, A. P. Vink, E. van der Kolk, C. W. E. van Eijk, K. W. Krämer, H. U. Güdel, W. M. Higgins and K. S. Shah
Level location and spectroscopy of Ce³⁺, Pr³⁺, Er³⁺, and Eu²⁺ in LaBr₃
J. Lumin. 117, 147-155 (2006)      Abstract                 

A. Bessière, P. Dorenbos, C. W. E. van Eijk, K. W. Krämer, H. U. Güdel and A. Galtayries
Scintillation and anomalous emission in elpasolite Cs₂LiLuCl₆:Ce³⁺
J. Lumin. 117, 187-198 (2006)      Abstract                 

M. D. Birowosuto, P. Dorenbos, J. T. M. de Haas, C. W. E. van Eijk, K. W. Krämer and H. U. Güdel
Optical spectroscopy and luminescence quenching of LuI₃:Ce³⁺
J. Lumin. 118, 308-316 (2006)      Abstract                 

Annina Aebischer, Marc Hostettler, Jürg Hauser, Karl Krämer, Thomas Weber, Hans Ulrich Güdel and Hans-Beat Bürgi
Structural and Spectroscopic Characterization of Active Sites in a Family of Light-Emitting Sodium Lanthanide Tetrafluorides
Angew. Chem. 118, 2869-2873 (2006)      Abstract                       
Angew. Chem. Int. Ed. 45, 2802-2806 (2006)      Abstract                       

D. Schaniel, Th. Woike, J. Schefer, V. Petrícek, K. W. Krämer, and H. U. Güdel
Neutron diffraction shows a photoinduced isonitrosyl linkage isomer in the metastable state SI of Na₂[Fe(CN)₅NO]·2D₂O
Phys. Rev. B 73, 174108/1-5 (2006)      Abstract                 

K. W. Krämer, P. Dorenbos, H. U. Güdel and C. W. E. van Eijk
Development and characterization of highly efficient new cerium doped rare earth halide scintillator materials
J. Mater. Chem. 16, 2773-2780 (2006)      Abstract                                   

M. D. Birowosuto, P. Dorenbos, C. W. E. van Eijk, K. W. Krämer and H. U. Güdel
High-light-output scintillator for photodiode readout: LuI₃:Ce³⁺
J. Appl. Phys. 99, 123520/1-4 (2006)      Abstract                 

M. D. Birowosuto, P. Dorenbos, C. W. E. van Eijk, K. W. Krämer and H U Güdel
Scintillation properties and anomalous Ce³⁺ emission of Cs₂NaREBr₆:Ce³⁺ (RE = La,Y,Lu)
J. Phys.: Condens. Matter 18, 6133-6148 (2006)      Abstract                 

M. D. Birowosuto, P. Dorenbos, C. W. E. van Eijk, K. W. Krämer and H. U. Güdel
PrBr₃: Ce³⁺: A New Fast Lanthanide Trihalide Scintillator
IEEE Trans. Nucl. Sci. 53, 3028-3030 (2006)      Abstract                 

M. D. Birowosuto, P. Dorenbos, J. T. M. de Haas, C. W. E. van Eijk, K. W. Krämer and H. U. Güdel
Thermal-neutron scintillator: Ce³⁺ activated Rb₂LiYBr₆
J. Appl. Phys. 101, 066107/1-3 (2007)      Abstract                 

M. D. Birowosuto, P. Dorenbos, C. W. E. van Eijk, K. W. Krämer and H. U. Güdel
Scintillation and luminescence properties of Ce³⁺ doped ternary cesium rare-earth halides
Phys. Stat. Sol. A 204, 850-860 (2007)      Abstract                 

H. B. Braun, J. Kulda, B. Roessli, D. Visser, K. W. Krämer, H. U. Güdel and P. Böni
Chiral quantum excitations in the anisotropic antiferromagnet CsCoBr₃
J. Magn. Magn. Mater. 310, 1194-1196 (2007)      Abstract                 

J. Grimm, J. Fleniken, K. W. Krämer, D. Biner, U. Happek and H. U. Güdel
On the determination of photoionization thresholds of Ce³⁺ doped Cs₃LuCl₆, Cs₂LiLuCl₆ and Cs₂LiYCl₆ by thermoluminescence
J. Lumin. 122-123, 325-328 (2007)      Abstract                 

D. Schaniel, M. Imlau, T. Weisemoeller, T. Woike, K. W. Krämer and H.-U. Güdel
Photoinduced Nitrosyl Linkage Isomers Uncover a Variety of Unconventional Photorefractive Media
Adv. Mater. 19, 723-726 (2007)      Abstract                                   

J. Grimm, O. S. Wenger, K. W. Krämer and H. U. Güdel
4f–4f and 4f–5d excited states and luminescence properties of Tm²⁺- doped CaF₂, CaCl₂, SrCl₂ and BaCl₂
J. Lumin. 126, 590-596 (2007)      Abstract                 

Dominik Schaniel, Benoit Cormary, Isabelle Malfant, Lydie Valade, Theo Woike, Bernard Delley, Karl W. Krämer and Hans-Ueli Güdel
Photogeneration of two metastable NO linkage isomers with high populations of up to 76% in trans-[RuCl(py)₄(NO)][PF₆]₂·¹/₂H₂O
Phys. Chem. Chem. Phys. 9, 3717-3724 (2007)      Abstract                 

M. D. Birowosuto, P. Dorenbos, C. W. E. van Eijk, K. W. Krämer and H. U. Güdel
Thermal quenching of Ce³⁺ emission in PrX₃ (X = Cl, Br) by intervalence charge transfer
J. Phys.: Condens. Matter 19, 256209/1-16 (2007)      Abstract                 

L. Schnelzer, O. Waldmann, M. Horvatić, S. T. Ochsenbein, S. Krämer, C. Berthier, H. U. Güdel and B. Pilawa
Huge Transverse Magnetic Polarization in the Field-Induced Phase of the Antiferromagnetic Molecular Wheel CsFe₈
Phys. Rev. Lett. 99, 087201/1-4 (2007)      Abstract                 

Dominik Schaniel, Theo Woike, Bernard Delley, Daniel Biner, Karl W. Krämer and Hans-Ueli Güdel
Generation of one light-induced metastable nitrosyl linkage isomer in [Pt(NH₃)₄Cl(NO)]Cl₂ in the red spectral range
Phys. Chem. Chem. Phys. 9, 5149-5157 (2007)      Abstract                       

C. W. E. van Eijk, H. U. Güdel , M. D. Birowosuto, P. Dorenbos and K. W. Krämer
High Light Yield Fast Scintillator
World Intellectual Property Organization,
Int. patent number WO 2007/031583 A1, 22.03.2007      Abstract                 

M. Imlau, V. Dieckmann, T. Weisemoeller, D. Schaniel, T. Woike, K. W. Krämer and H.-U. Güdel
Tuning Ability of Photosensitive ML₅NO-Molecules
in "Controlling Light with Light: Photorefractive Effects, Photosensitivity, Fiber Gratings, Photonic Materials and More",
OSA Technical Digest (CD), Optical Society of America, Paper SuC5 (2007)      Abstract                 

E. van der Kolk, P. Dorenbos, K. Krämer, D. Biner and H. U. Güdel
High-resolution luminescence spectroscopy study of down-conversion routes in NaGdF₄:Nd³⁺ and NaGdF₄:Tm³⁺ using synchrotron radiation
Phys. Rev. B 77, 125110/1-7 (2008)      Abstract                 

Ch. Rüegg, B. Normand, M. Matsumoto, A. Furrer, D. F. McMorrow, K. W. Krämer, H.-U. Güdel, S. N. Gvasaliya, H. Mutka and M. Boehm
Quantum Magnets under Pressure: Controlling Elementary Excitations in TlCuCl₃
Phys. Rev. Lett. 100, 205701/1-4 (2008)      Abstract                 

M. D. Birowosuto, P. Dorenbos, K. W. Krämer and H. U. Güdel
Ce³⁺ activated LaBr_3–xI_x: High-light-yield and fast-response mixed halide scintillators
J. Appl. Phys. 103, 103517/1-6 (2008)      Abstract                 

M. Danang Birowosuto, Pieter Dorenbos, Johan T. M. de Haas, Carel W. E. van Eijk, Karl W. Krämer and H. U. Güdel
Li-Based Thermal Neutron Scintillator Research; Rb₂LiYBr₆ : Ce³⁺ and Other Elpasolites
IEEE Trans. Nucl. Sci. 55, 1152-1155 (2008)      Abstract                 

M. Danang Birowosuto, Pieter Dorenbos, G. Bizarri, Carel W. E. van Eijk, Karl W. Krämer and H. U. Güdel
Temperature Dependent Scintillation and Luminescence Characteristics of GdI₃: Ce³⁺
IEEE Trans. Nucl. Sci. 55, 1164-1169 (2008)      Abstract                 

R. Valiente, I. Hernández, F. Rodríguez, F. Aguado, H. U. Güdel and K. Krämer
High-pressure induced absorption line narrowing in Cs₃Yb₂Cl₉
J. Phys. Conf. Ser. 121, 042002/1-5 (2008)      Abstract                 

B. Thielemann, Ch. Rüegg, H. M. Rønnow, A. M. Läuchli, J.-S. Caux, B. Normand, D. Biner, K. W. Krämer, H.-U. Güdel, J. Stahn, K. Habicht, K. Kiefer, M. Boehm, D. F. McMorrow and J. Mesot
Direct Observation of Magnon Fractionalization in the Quantum Spin Ladder
Phys. Rev. Lett. 102, 107204/1-5 (2009)      Abstract                 

R. Valiente, F. Rodríguez, J. González, H. U. Güdel, R. Martín-Rodríguez, L. Nataf, M. N. Sanz-Ortiz and K. Krämer
High pressure optical spectroscopy of Ce³⁺-doped Cs₂NaLuCl₆
Chem. Phys. Lett. 481, 149-151 (2009)      Abstract                 

J. J. Eilers, D. Biner, J. T. van Wijngaarden, K. Krämer, H.-U. Güdel and A. Meijerink
Efficient visible to infrared quantum cutting through downconversion with the Er³⁺–Yb³⁺ couple in Cs₃Y₂Br₉
Appl. Phys. Lett. 96, 151106/1-3 (2010)      Abstract                 

A. Furrer, K. W. Krämer, Th. Strässle, D. Biner, J. Hauser and H. U. Güdel
Magnetic and neutron spectroscopic properties of the tetrameric nickel compound [Mo₁₂O₂₈(m₂-OH)₉(m₃-OH)₃{Ni(H₂O)₃}₄]·13H₂O
Phys. Rev. B 81, 214437/1-10 (2010)      Abstract                 

C. Renero-Lecuna, R. Martín-Rodríguez, R. Valiente, J. González, F. Rodríguez, K. W. Krämer and H. U. Güdel
Origin of the High Upconversion Green Luminescence Efficiency in b-NaYF₄:2%Er³⁺,20%Yb³⁺
Chem. Mater. 23, 3442-3448 (2011)      Abstract