Crystal preparation and properties of cesium tin(II) trihalides

CH3NH3SnBrxI3-x (x = 0-3), ein Sn(II)-System mit kubischer Perowskitstruktur / CH3NH3SnBrxI3-x(x = 0-3), a Sn(II)-System with Cubic Perovskite Structure

“…Die in den meisten Fällen anzutreffende Liganden Verteilung niederer Symmetrie kann mit der Mischung von s-und p-Valenzzuständen erklärt werden [2], Eines dieser seltenen Beispiele mit stereochemisch inaktiven ns 2 -Elektronen ist das schwarze, im kubischen Perowskitgitter kristallisierende CsSnBr3 [3,4], das sich im Gegensatz zu den übrigen Alkali-Zinn(II)-Halogeniden durch intensive Eigenfarbe und elektrische Leitfähigkeit auszeichnet [5,6], Das Sn(II)-Ion ist hier streng oktaedrisch von den Anionen umgeben.…”

207Pb and 205Tl NMR on Perovskite Type Crystals APbX3 (A = Cs, Tl, X = Br, I)

“…Several studies have been reported for the com pounds CsSnX3, with X = Cl, Br, I. Scaife et al [23] studied these systems by X-ray diffraction and by N Q R and Barrett [24] conducted Sn-M össbauer spec troscopy on these ternary Sn(II) halides. Investiga tions on mixed crystals CsSnBr3_xY;c, Y = Cl, I, have been included in the work of these authors.…”

Anharmonic stabilization and band gap renormalization in the perovskiteCsSnI3

“…The fact that experiments observe only the cubic phase at temperatures above 440 K [10,12,18] indicates that this phase corresponds to a minimum of the free energy F . In the quasiharmonic approximation [22], F is replaced with F (ω,T ), the free energy of an ensemble of oscillators of temperature T with frequencies ω = {ω 1 ,ω 2 ,...ω ν }: V 0 is the energy of the ions in their equilibrium positions, and k B the Planck and Boltzmann constants, and n B the Bose-Einstein distribution function.…”

“…Unlike its famous cousin MAPbI 3 (MA = methylammonium), CsSnI 3 has (i) no permanent cationic dipole moment [16], (ii) reduced spin-orbit coupling due to the lighter mass of Sn [17], and (iii) a high-symmetry cubic (B-α) phase characterized by many studies [10,12,18]. However, theoretical investigations [11,[19][20][21] consistently find the B-α phase to be unstable against spontaneous rotation of the SnI 6 octahedra, so on energetic grounds this phase should not exist at all.…”