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Compositional engineering through metal mixing is an important strategy for tailoring the structural and functional properties of hybrid metal halide perovskites.[1] While extensive research has focused on mixing organic cations at the A-site and halide anions at the X-site,[2] the effects of B-site mixing on phase stability and structural transitions remain less explored. In this work, we investigate a series of methylammonium lead–tin bromide perovskites, $MAPb_1$$_-$$_x$Sn$_xBr_3$, to establish the relationship between metal composition, crystal structure, and temperature-dependent phase behaviour.[3]
Mixed-metal perovskites with different Sn contents were synthesized, and their compositions and structural characteristics were examined using powder X-ray diffraction (PXRD) and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDX). These complementary methods enabled the assessment of phase formation, changes in the crystal lattice, and the incorporation of tin into the lead-based perovskite framework. The systematic evolution of the diffraction patterns with increasing Sn content demonstrates the structural compatibility of the two end-member compounds and the formation of mixed-metal compositions.
Temperature-dependent studies, including differential scanning calorimetry (DSC), were used to investigate phase transitions across the compositional series. The results were combined with dielectric spectroscopy measurements to construct a temperature–composition phase diagram and evaluate the influence of B-site mixing on the structural phase behaviour. The introduction of tin slightly stabilizes the cubic phase, while the overall changes in structural transition temperatures remain relatively modest compared with those commonly associated with A-site or X-site mixing. Nevertheless, metal mixing affects the ordering and dynamics of the methylammonium cations, highlighting the interplay between the inorganic framework and the organic sublattice.
This study demonstrates the feasibility of preparing mixed Pb–Sn bromide perovskites across a broad compositional range and emphasizes the importance of systematic compositional and temperature-dependent characterization. Understanding how B-site mixing influences phase stability provides a basis for the rational design of hybrid perovskites with tailored structural and functional properties, relevant to the development of optoelectronic materials.
References:
[1] D. S. Kreiman, O. I. Kucheriv, B. Laurentiu, S. Shova and I. A. Gural’skiy, Mater. Chem. Front., 2026, 10, 3056–3067.
[2] O. I. Kucheriv, D. A. Haleliuk, S. Shova and I. A. Gural’skiy, Dalt. Trans., 2025, 54, 1618–1624.
[3] G. Rimkus, S. Balčiu̅nas, H. R. Petrosova, O. I. Kucheriv, R. Lemežis, V. Klimavičius, V. Kalendra, J. Banys, I. A. Gural’skiy and M. Šimėnas, Chem. Mater., 2025, 37, 1314–1320.
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