Optical, Photoelectric,and Electrocatalytic Propertiesof Quaternary Sulfides RE MSnS (RE = La-Nd; M = Ti-Cu, Cd)

초록

Several series of quaternary sulfides RE 3 M 1-x SnS7 (RE = La-Nd; M = Ti-Cu, Cd) were synthesized by direct reaction of the elements at 1000 degrees C and their crystal structures were determined by powder X-ray diffraction, as well as single-crystal X-ray diffraction for many members. Most adopt the noncentrosymmetric La3Mn0.5SiS7-type structure (hexagonal, space group P63) consisting of one-dimensional stacks of Sn-centered tetrahedra and columns of face-sharing M-centered octahedra. With focus placed on the La-containing series La3 M 1-x SnS7, further characterization was performed using X-ray photoelectron and electron paramagnetic spectroscopy. Their optical band gaps ranged from 1.5 to 2.5 eV. Selected members of this series were evaluated for various functional properties. La3Mn0.5SnS7 and La3Cd0.5SnS7 show moderate second harmonic generation at 1800 nm but high laser-induced damage thresholds and improved figures of merit relative to benchmark infrared nonlinear optical materials. La3Fe0.5SnS7 exhibits high photocurrent density suitable for photoelectric energy conversion. La3Ni0.5SnS7 demonstrates electrocatalytic activity for the oxygen evolution reaction in water.

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