Browsing by Author "Chen, Guan-Ruei"

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Synthesis and characterization of new quaternary polyselenide Ba4TMSbSe12 (TM = Nb, Ta)
(2019-09-01)
Chung, Ming-Yan
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Chen, Guan-Ruei
;
Lee, Chi-Shen
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交大名義發表
;
應用化學系
Two new quaternary polyselenides, Ba4TMSbSe12 (TM = Nb, Ta), are synthesized using a solid state reaction. They crystallize in a new structural type with a P-1 triclinic space group, characterized according to single-crystal X-ray diffraction. The structure is alternately stacked using isolated NbSe95- and SbSe33-, which are separated by Ba2+. The structure contains the NbSe95- unit with a bipentagonal pyramidal shape coordinated with Se2- and Se-2(2-) in monodenteate and bidentate modes. The vibrational property of the diselenide Se-2(2-) unit was studied using Raman spectrum analysis. ultraviolet-visible diffused reflectance and temperature-dependent resistivity measurements indicate semiconductor behaviors. Calculations of electronic structures indicate the presence of a band gap and strong Se-Se interactions in the diselenide group, which experimentally supports the measured physical properties.
Synthesis and Characterizations of new quaternary selenide Sn4(In/Sb)14Se25
(2016-01-01)
Lee, Chi-Shen
;
Chen, Guan-Ruei
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交大名義發表
;
National Chiao Tung University
Ternary Chalcogenides GeSb2Se3 and Ge3Sb4Se7 Containing a (1)(infinity)[Sb2Se2](2-) 1D Chain and a 2D Structure Related to SnSe
(2020-08-17)
Chen, Guan-Ruei
;
Li, Chien-He
;
Yu, Ching-Yi
;
Wang, Ming-Fang
;
Lee, Chi-Shen
Ternary chalcogenides, GeSb2Se3 and Ge3Sb4Se7, were synthesized and characterized. These chalcogenides are the first ternary selenides in a ternary Ge-Sb-Se system that feature a layer structure related to black phosphorus and SnSe-type structures. Both compounds contain a(infinity)( 1)[Sb2Se2](2-) unit with Sb+ cations in a zigzag Sb-Sb chain structure, and Sb3+ cations in a distorted NaCl100-type of (1)(infinity)[Gen-2Sb2Sen](2+) unit (n = 4, 5). These materials exhibit n-type semiconducting properties with thermal conductivity significantly lower than that of GeSe and Sb2Se3, which could be correlated to the 1D Sb+ chain and disordered sites with different Ge/Sb compositions. It is anticipated that these newly discovered ternary chalcogenides may provide unique properties with enhanced thermoelectric properties.