Composition effects on structure and optical properties in double perovskite derivatives semiconductors Cs2SnI6−xBrx (x = 0–6)

Abstract

We have proved that Cs2SnI6−xBrx (x = 0–6) can be eutectic in the whole composition, and the eutectic phase has the similar cubic symmetry with both of the end phases (space group of Fm3¯m). The lattice constant decreases from around 11.67 Å (x = 0) to around 10.83 Å (x = 6). Hall-plot analysis shows that the strain varies sharply near the two end materials, while the strain is almost independent of Br content at the middle Br content. The bandgap, on the other hand, increases from 1.26 eV to 2.93 eV with increasing the Br content, which might be expected in fabricating the continuous junction solar cells.

Stable Lead-Free Cesium Tin Halide Double-Perovskite Nanocrystals Embedded in Polydimethylsiloxane for Candlelight Light-Emitting Diodes

“…A slight shift in the diffraction angle of Cs 2 SnBr 6 DPNCs compared with the reference (mp-641923) may be due to the distortion of crystal lattices such as vacancies, which caused lattice contraction . Moreover, the peak positions of XRD observed for the Cs 2 SnBr 6 DPNCs well matched those in a previous report, , confirming that Cs 2 SnBr 6 DPNCs adopted the cubic phase of the Fm 3̅ m space group. In addition, the reference XRDs of bulk CsBr, SnBr 2 , and SnBr 4 are also shown in Figure S5.…”

“…However, Sn­(II)-based PNCs with chemical instability limit the investigation of their optical properties. − Sn­(II) is easily oxidized to the more stable Sn­(IV) under atmospheric conditions. The oxidation of PNCs is problematic because they have a high surface-to-volume ratio. , Therefore, Sn­(II) can be replaced with Sn­(IV) to avoid its oxidation. − This approach modifies the standard PNC structures and leads to the formation of vacancy-ordered DPNC structures. ,, Herein, we listed Sn­(II) and Sn­(IV)-based Pb-free PNCs that show structure types and PL properties (Table S1). The crystal structures, the energy-band structures, and the PL mechanic properties of studies on Sn­(IV)-based DPNCs are rarely reported.…”

Lattice Dynamics and Optoelectronic Properties of Vacancy-Ordered Double Perovskite Cs2TeX6 (X = Cl–, Br–, I–) Single Crystals

“…To test this hypothesis of a transition from a more molecule-like energy level structure in Cs 2 TeCl 6 and Cs 2 TeBr 6 to a more typical dispersive band structure in Cs 2 TeI 6 , electronic structure calculations were performed and are shown in the next section. This electronic transition from dominant 0D-behavior to dominant 3D-behavior is also apparent in the absorbance spectrum of the isostructural Cs 2 SnBr 6– x I x ( x = 0–6) single crystals, but to the authors’ knowledge, this is the first report of the mechanism behind this transition in 0D perovskites.…”

“…Thus, a detailed analysis of the atomic structure and fluctuations of the octahedral building blocks in perovskites, particularly in the mixed-halide perovskites, is necessary to have a better understanding of the structural, vibrational, and electronic behavior of these systems. The influence of the fundamental octahedral building block can be better resolved in inorganic lead-free vacancy-ordered double perovskites of form A 2 BX 6 . − The A 2 BX 6 system is a variation of charge-ordered double perovskites where one of the B-site cations has been replaced by a vacancy . As this vacancy replacement is systematic, every other octahedron is missing in the crystal structure.…”

The Influence of Spontaneous Oxidative Conversion on the Characteristics of Lead‐Free Halide Perovskite CsSn(IxBr1−x)3 and on the Performance of Perovskite Light‐Emitting Diodes

“…As for Cs 2 Sn(I x Br 1− x ) 6 , the bandgap was increasing from about 1.3 to 3.0 eV while decreasing the x value from 1 to 0. [ 42,43 ] Taking x = 0.5 as example, that is Cs 2 Sn(I 0.5 Br 0.5 ) 6 the PL peak was located at 826 nm. The data of the present study showed that the PL peak of CsSnI 0.5 Br 0.5 was located at 770 nm.…”