Ba₂AsGaSe₅: A New Quaternary Selenide with the Novel [AsGaSe₅]^4– Cluster and Interesting Photocatalytic Properties

Abstract

The new zero-dimensional selenide Ba2AsGaSe5 was synthesized via a solid-state reaction at 900 °C. It belongs to the orthorhombic space group Pnma with a = 12.632(3) Å, b = 8.9726(18) Å, c = 9.2029(18) Å, and Z = 4. In the structure, the As atom adopts trigonal-pyramidal coordination owing to the stereochemically active 4s(2) lone pair electrons and the Ga atom is tetrahedrally coordinated with four Se atoms. The AsSe3 trigonal pyramids share edges with GaSe4 tetrahedra to form novel [AsGaSe5](4-) clusters, which are further separated from each other by Ba(2+) cations. The optical band gap was determined as 1.39 eV according to UV-vis-NIR diffuse reflectance spectroscopy. Interestingly, the photocatalytic behavior investigated by decomposing rhodamine B indicates that the compound displays a 6.5 times higher photocatalytic activity than does P25.

Structural and physical properties of 99 complex bulk chalcogenides crystals using first-principles calculations

“…Another group of chalcogenide crystals in the form of Ag 2 XYSe 4 (X = Ba, Sr; Y = Ge, Sn) also become attractive because of their ability in converting heat energy to electricity 36 . Most recent studies show that quaternary chalcogenide crystals with compositions A I B II C IV Q 4 and A I 2 B II C IV Q 5 such as in BaZnSiSe 4 , SrCdGeSe 4 , and Ba 2 AsGaSe 5 are crucial in medical and military applications due to their ideal infrared nonlinear optical (NLO) properties and high visible-light-induced photocatalytic reactivity 37 – 39 . Only a small fraction of such NLO materials with second harmonic generation (SHG) effect are commercially available.…”

Synthesis, Crystal Structures, Optical Properties and Theoretical Calculations of Two Metal Chalcogenides Ba2AlSbS5 and Ba2GaBiSe5

“…With stereochemically active lone-pair electrons, the above trivalent cations exhibit a flexible coordination environment for the formation of M III 'Q n units (n = 3~6; Q = chalcogen), which offers an opportunity to affect their crystal structures and physicochemical properties [13][14][15][16][17][18][19][20][21][22][23][24]. For example, AAsQ 2 (A = Li, Na; Q = S, Se) [15] and A 3 Ta 2 AsS 11 (A = K, Rb) [13] compounds feature [AsS 3 ] 3-pyramids and show strong second harmonic generation (SHG) responses; BaBiTe 3 , AgBi 3 S 5 and A 2 Bi 8 Se 13 (A = Rb, Cs) compounds exhibit small bandgaps and have promising potential as thermoelectric materials [22][23][24]; Ba 2 GaAsSe 5 shows novel [AsGaSe 5 ] 4− anions and high visible-light-induced photocatalytic reactivity [17]. In addition, overall literature research indicates that the above M III 'Q n units can bridge other functional units to form a variety of extended structures [16].…”

“…Moreover, Ba atoms have flexible coordination numbers (6 to 10) with chalcogens, owing to their large ionic radii, which can also produce distinctive structures in combination with M III 'Q n units. So far, many efforts have been focused on the Ba-M III-M III '-Q system, and several compounds with the Ba 2 M III M III 'Q 5 (M III = Ga, In) formula have been discovered [17][18][19][20][21]. Unfortunately, their structural changes and theoretical calculations have not been systematically studied.…”

Rb2CuSb7S12: Quaternary Antimony-Rich Semiconductor Featuring a Three-Dimensional Open Framework and Exhibiting an Intriguing Photocurrent Response

“…Moreover, inspired by recent studies that most of the group 15-containing chalcogenides demonstrate intriguing photocatalytic activities, ,,− we investigated the photocurrent properties of Rb 2 CuSb 7 S 12 . Figure displays the photocurrent–time curves of Rb 2 CuSb 7 S 12 in several on–off cycles under simulated solar light illumination, and the repeatable features indicate that it is a typical n-type (electron conductive) semiconductor.…”