TY - JOUR
T1 - Phase Transition, Conformational Exchange, and Nonlinear Optical Third Harmonic Generation of ACsP2Se8 (A = K, Rb, Cs)
AU - Haynes, Alyssa S.
AU - Banerjee, Abhishek
AU - Saouma, Felix O.
AU - Otieno, Calford O.
AU - Jang, Joon I.
AU - Kanatzidis, Mercouri G.
N1 - Funding Information:
This work was supported by the National Science Foundation Grant DMR-1410169. Part of this work utilized the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, supported by the U.S. DOE under Contract No. DE-AC02-06CH11357. SEM experiments were conducted in the EPIC facility (NUANCE Center-Northwestern University), supported by the MRSEC program at the Materials Research Center with the National Science Foundation Grant DMR-1121262, the International Institute for Nanotechnology (IIN), and the State of Illinois through the IIN. Raman, NMR, and MS measurements were performed in the IMSERC facility at Northwestern University and supported through the university. We thank Gooch and Housego for supplying the AgGaSe2 crystal. A.S.H. gratefully acknowledges support through a Graduate Research Fellowship by the National Science Foundation under Grant No. DGE-1324585. A.S.H. also appreciates the mentorship from Drs. Greg Halder and Daniel Shoemaker related to the synchrotron in situ PXRD measurements, Drs. Yongbo Zhang and Yuyang Wu for solution and solid-state NMR experiments, and Saman Shafaie for mass spectroscopy studies.
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/4/26
Y1 - 2016/4/26
N2 - The soluble molecular selenophosphate salts ACsP2Se8 (A = K, Rb, Cs) crystallize in the orthorhombic space group Ccce with a = 14.982(3) Å, b = 24.579(5) Å, and c = 13.065(3) Å for the Cs salt and a = 14.782(3) Å, b = 23.954(5) Å, and c = 13.044(3) Å for the K analogue. ACsP2Se8 is composed of the molecular 6-membered ring, [P2Se8]2-, in the twist conformation charge balanced by alkali metals. The band gaps of these compounds are 2.44 ± 0.2 eV for Cs2P2Se8, 2.41 ± 0.2 eV for RbCsP2Se8, and 2.36 ± 0.2 eV for KCsP2Se8. The amorphous versions of these materials can be made by water quenching the melt and have band gaps for all ACsP2Se8 of 2.12 ± 0.2 eV. Raman spectroscopic studies exhibit active modes of PSe4 and Se-Se in the compound. Solution 31P NMR studies shed light into the interesting conformational fluxionality of the [P2Se8]2- anion, including a conformation that has not been previously observed. Thermal analysis reveals ACsP2Se8 exhibits a phase transition, which we investigate by in situ synchrotron powder X-ray diffraction. Third harmonic generation (THG) nonlinear optical measurements determined the THG coefficient, χ(3), for amorphous and crystalline Cs2P2Se8 of 1.8 ± 0.2 × 105 pm2/V2 and 2.4 ± 0.1 × 105 pm2/V2, respectively.
AB - The soluble molecular selenophosphate salts ACsP2Se8 (A = K, Rb, Cs) crystallize in the orthorhombic space group Ccce with a = 14.982(3) Å, b = 24.579(5) Å, and c = 13.065(3) Å for the Cs salt and a = 14.782(3) Å, b = 23.954(5) Å, and c = 13.044(3) Å for the K analogue. ACsP2Se8 is composed of the molecular 6-membered ring, [P2Se8]2-, in the twist conformation charge balanced by alkali metals. The band gaps of these compounds are 2.44 ± 0.2 eV for Cs2P2Se8, 2.41 ± 0.2 eV for RbCsP2Se8, and 2.36 ± 0.2 eV for KCsP2Se8. The amorphous versions of these materials can be made by water quenching the melt and have band gaps for all ACsP2Se8 of 2.12 ± 0.2 eV. Raman spectroscopic studies exhibit active modes of PSe4 and Se-Se in the compound. Solution 31P NMR studies shed light into the interesting conformational fluxionality of the [P2Se8]2- anion, including a conformation that has not been previously observed. Thermal analysis reveals ACsP2Se8 exhibits a phase transition, which we investigate by in situ synchrotron powder X-ray diffraction. Third harmonic generation (THG) nonlinear optical measurements determined the THG coefficient, χ(3), for amorphous and crystalline Cs2P2Se8 of 1.8 ± 0.2 × 105 pm2/V2 and 2.4 ± 0.1 × 105 pm2/V2, respectively.
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U2 - 10.1021/acs.chemmater.6b00551
DO - 10.1021/acs.chemmater.6b00551
M3 - Article
AN - SCOPUS:84964608758
SN - 0897-4756
VL - 28
SP - 2374
EP - 2383
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 7
ER -