Ba₂Si₃P₆: 1D Nonlinear Optical Material with Thermal Barrier Chains

Abstract

A novel barium silicon phosphide was synthesized and characterized. Ba2Si3P6 crystallizes in the noncentrosymmetric space group Pna21 (No. 33) and exhibits a unique bonding connectivity in the SiP polyanion not found in other compounds. The crystal structure is composed of SiP4 tetrahedra connected into one-dimensional double-tetrahedra chains through corner sharing, edge sharing, and covalent P-P bonds. Chains are surrounded by Ba cations to achieve an electron balance. The novel compound exhibits semiconducting properties with a calculated bandgap of 1.6 eV and experimental optical bandgap of 1.88 eV. The complex pseudo-one-dimensional structure manifests itself in the transport and optical properties of Ba2Si3P6, demonstrating ultralow thermal conductivity (0.56 W m-1 K-1 at 300 K), promising second harmonic generation signal (0.9 × AgGaS2), as well as high laser damage threshold (1.6 × AgGaS2, 48.5 MW/cm2) when compared to the benchmark material AgGaS2. Differential scanning calorimetry reveals that Ba2Si3P6 melts congruently at 1373 K, suggesting that large single crystal growth may be possible. Disciplines

Polymorphism of Ba2SiP4

“…The possibility of the formation of homonuclear phosphorus bonding distinguishes the family of phosphidosilicates from the oxido‐ and nitridosilicates. Isolated P–P bonding was described in AlSiP 3 , Ca 3 Si 8 P 14 , Ba 2 Si 3 P 6 and Ba 4 Si 3 P 8 , for example, whereas in LaSi 2 P 6 up to four different polyphosphide anions (P n ) –( n +2) with n = 3–6 and in Li 3 Si 3 P 7 [4a] polyphosphide chains exist. Tetragonal Ba 2 SiP 4 ‐ tI 28 is the first example where all SiP 4 tetrahedra are connected by P–P bonds.…”

“…Tetragonal Ba 2 SiP 4 ‐ tI 28 is the first example where all SiP 4 tetrahedra are connected by P–P bonds. Currently the Ba‐Si‐P ternary system attracts attention regarding possible NLO and thermoelectric properties . Therefore, we focused upon this compounds and found the high‐temperature enantiotropic polymorph Ba 2 SiP 4 ‐ oP 56, in which all SiP 4 tetrahedra are linked by homonuclear phosphorus bonds, as well, being the second example for this structure motif.…”

“…DFT calculations predict an indirect optical bandgap of about 1.7 eV. described in AlSiP 3 , [16] Ca 3 Si 8 P 14 , [6] Ba 2 Si 3 P 6 [17] and Ba 4 Si 3 P 8 , [18] for example, whereas in LaSi 2 P 6 up to four different polyphosphide anions (P n ) -(n+2) with n = 3-6 and in Li 3 Si 3 P 7 [4a] polyphosphide chains exist. Tetragonal Ba 2 SiP 4 -tI28 [19] is the first example where all SiP 4 tetrahedra are connected by P-P bonds.…”

LiSi3As6and Li2SiAs2with flexible SiAs2polyanions: synthesis, structure, bonding, and ionic conductivity

“…64), Pearson symbol oS-80. Similar to a number of complex ternary silicon phosphides, [33][34][35][36][37][38][39][40] LiSi 3 As 6 exhibits several different bonding schemes including corner sharing SiAs 4 tetrahedra, Si-Si dumbbells, and As-As bonds. The structure is composed of alternating planes of SiAs 4 tetrahedra and Si 2 As 6 antiprisms along the b-direction (Fig.…”

Flux Growth of Phosphide and Arsenide Crystals

“…The volatility of P and As has resulted in poor exploration of many metal-phosphorus (arsenic) phase diagrams in the areas of high pnictogen content. Nevertheless, compounds with substantial P(As) content often exhibit interesting chemistry and useful practical properties, with potential applications as heat conductors, thermoelectrics, catalysts, and non-linear optical materials (Soheilnia et al, 2007;Lindsay et al, 2013;Dolyniuk et al, 2017;Nuss et al, 2017;Pöhls et al, 2017;Li et al, 2018;Owens-Baird et al, 2018, 2019Woo et al, 2018;Coleman et al, 2019;Mark et al, 2019;Yu et al, 2019).…”