K2P2Se6: Comparison with AgGaSe2

Wavelength (nm)

600 700 800 900 1000

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lativ

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cien

cy

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1000

(A)

(B)

• The K2P2Se6 have parallel helical chains of 1/∞[P2Se62-]

formed by the polymerization of the [P2Se6]4- anion.• The compound is a glass former and shows reversible glass-

crystal phase-change behavior. • K2P2Se6 exhibits some of the highest second harmonic

generation non-linear optical response known for any material operating in the infrared region of the spectrum.

1 1.5 2 2.5 3 3.5 4 4.5 5

K2P2Se6 CrystalRb2P2Se6 CrystalK2P2Se6 GlassRb2P2Se6 Glass

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0.5

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2.5

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3.5

Ab

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. u

.)

Energy, eV

Phase matching

SHG response: 50x larger than the commercial material AgGaSe2.

Solid State Chalcogenides: What to expect from selenophosphates

Mercouri Kanatzidis, Northwestern University, DMR 0702911

K2P2Se6: a helix with very strong non-linear optical property

• The new material, K2P2Se6 which we have discovered has strong chirality combined with phase-change behavior which could enable it to be explored as a multi-functional switchable material. • The glass forming property of these materials makes them potentially valuable for producing IR optical glass fibers. • K2P2Se6 exhibits wide IR transparency up to 19.2 μm and coupled with its very large SHG response, and type-I phase-matchable, is the top performing NLO material in the IR region.

• Possible applications: •optical parametric oscillators• frequency doubling for long wave IR wavelengths, i.e. generation of light with a doubled frequency (half the wavelength)

Solid State Chalcogenides: What to expect from selenophosphates

Mercouri Kanatzidis, Northwestern University, DMR 0702911

Graduate Students: In Chung (PhD 2007), Nan Ding (PhD 2007), Chris Malliakas (anticipated end of PhD 2007)

Post Doctorals: Dr. Emanouil Manos, PhD University of Ioannina, Dr. Ferdiand Poudeu, PhD University of Dresden, now Assistant Professor of Chemistry University of New Orleans; Dr.John Androulakis, PhD University of Crete.

International Exchange: Ms Seon Mi Park, Ewha Womans University, Seoul Korea, Prof. K. Paraskevopoulos, Aristotle University, Thessaloniki Greece. Prof. K. Chrisssafis, Aristotle University, Thessaloniki Greece.

Collaborators: Prof. Simon Billinge (Michigan State University), Prof. S. D. Mahanti (Michigan State University), Dr. Peter Chupas, Argonne National Laboratory, Prof., Prof. K. Paraskevopoulos, Aristotle University, Thessaloniki Greece.

Undergraduates: Marc Coussens, Jonathan Cave

Solid State Chalcogenides: What to expect from selenophosphates

Mercouri Kanatzidis, Northwestern University, DMR 0702911