Chemistry in Molten Alkali Metal Polyselenophosphate Fluxes. Influence of Flux Composition on Dimensionality. Layers and Chains in APbPSe₄, A₄Pb(PSe₄)₂ (A = Rb, Cs), and K₄Eu(PSe₄)₂

Abstract

The reaction of Pb and Eu with a molten mixture of A(2)Se/P(2)Se(5)/Se produced the quaternary compounds APbPSe(4), A(4)Pb(PSe(4))(2) (A = Rb,Cs), and K(4)Eu(PSe(4))(2). The red crystals of APbPSe(4) are stable in air and water. The orange crystals of A(4)Pb(PSe(4))(2) and K(4)Eu(PSe(4))(2) disintegrate in water and over a long exposure to air. CsPbPSe(4) crystallizes in the orthorhombic space group Pnma (No. 62) with a = 18.607(4) Å, b = 7.096(4) Å, c = 6.612(4) Å, and Z = 4. Rb(4)Pb(PSe(4))(2) crystallizes in the orthorhombic space group Ibam (No. 72) with a = 19.134(9) Å, b = 9.369(3) Å, c = 10.488(3) Å, and Z = 4. The isomorphous K(4)Eu(PSe(4))(2) has a = 19.020(4) Å, b = 9.131(1) Å, c = 10.198(2) Å, and Z = 4. The APbPSe(4) have a layered structure with [PbPSe(4)](n)()(n)()(-) layers separated by A(+) ions. The coordination geometry around Pb is trigonal prismatic. The layers are composed of chains of edge sharing trigonal prisms running along the b-direction. [PSe(4)](3)(-) tetrahedra link these chains along the c-direction by sharing edges and corners with the trigonal prisms. A(4)M(PSe(4))(2) (M = Pb, Eu) has an one-dimensional structure in which [M(PSe(4))(2)](n)()(n)()(-) chains are separated by A(+) ions. The coordination geometry around M is a distorted dodecahedron. Two [PSe(4)](3)(-) ligands bridge two adjacent metal atoms, using three selenium atoms each, forming in this way a chain along the c-direction. The solid state optical absorption spectra of the compounds are reported. All compounds melt congruently in the 597-620 degrees C region.

High Members of the 2D Ruddlesden-Popper Halide Perovskites: Synthesis, Optical Properties, and Solar Cells of (CH3(CH2)3NH3)2(CH3NH3)4Pb5I16

“…Optical diffuse-reflectance spectra were collected at room temperature with a Shimadzu UV-3600 PC double-beam, double-monochromator spectrophotometer on powdered samples, and BaSO 4 as a 100% reflectance reference. 53,54 The samples were irradiated with a halogen lamp (near IR/visible, 50 W, 2,000 hr) and a D 2 lamp (UV, 2,000 hr), and the spectra were recorded with a PbS photoconductive element (near IR) and a PMT (R928) detector from 2,500 to 200 nm.…”

Porous Azo‐Bridged Porphyrin–Phthalocyanine Network with High Iodine Capture Capability

“…[11a] At 273 K, the initial slope method gives aC O 2 /N 2 adsorption selectivity of 62.3 for AzoPPN,a nd the IAST calculation affords aC O 2 /N 2 selectivity of 38.4 (CO 2 /N 2 ,1 5:85;1 .0 bar;F igure 2b). The selectivityp erformance of AzoPPN is comparable to azo-linked ALPs (26-35, IAST) [11a] and highert han some well-studied POPss uch as PPF (15)(16)(17)(18)(19)(20)IAST) [12a] or CTF (14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)IAST). [12b] This encouraging CO 2 /N 2 selectivity of AzoPPN might be related to the N 2phobic character of the azo-linkage and permanent microporosity in the network.…”

“…The absorption spectra were converted from the corresponding reflectance data according to the Kubelka-Munk equation a/S = (1ÀR) 2 /2R, where R is the reflectance, a and S are the absorption and scattering coefficient, respectively. [16] UV/Vis spectra were recorded on aL amda 950 UV/Vis/ NIR spectrophotometer (Perkin-Elmer Instruments Co. Ltd.,U SA) and the quartz cell was 1cmp ath-length. Fourier transform infrared (FT-IR) spectra were recorded on aP erkin-Elmer Spectrum One FT-IR spectrometer (Perkin-Elmer Instruments Co. Ltd.,U SA).…”

New Type of 2D Perovskites with Alternating Cations in the Interlayer Space, (C(NH2)3)(CH3NH3)nPbnI3n+1: Structure, Properties, and Photovoltaic Performance

“…BaSO 4 was used as a non-absorbing reflectance reference, and reflectance data were converted to absorbance data via Kubelka-Munk transformation. [42][43][44] Photoluminescence spectra were collected on oriented crystals using Horiba LabRam Evolution high-resolution confocal Raman microscope spectrometer (600 g/mm diffraction grating) equipped with a diode CW laser (473 nm, 25 mW) and a Synapse CCD camera.…”