2026-10-11T20:38:30Z https://api.figshare.com/v2/oai

oai:figshare.com:article/34033696 2026-09-30T16:04:00Z category_1 category_915 category_21 category_24 category_873 category_39 portal_63 item_type_6 month_year_09_2026

Melting Point Depression and Glass-Forming Abilities in Pb- and Sn-Based Hybrid Perovskites with a Nonprimary Ammonium Cation Yi Xie (12835) Rayan Chakraborty (6630038) Akash Singh (652299) Timothy M. McWhorter (6581024) AM Milinda Abeykoon (13261687) Daniel Olds (4182145) Volker Blum (1274613) David B. Mitzi (1363923) Biophysics Physical Sciences not elsewhere classified Biotechnology Evolutionary Biology Chemical Sciences not elsewhere classified Ecology pair distribution function g ., associated accessible atomic arrangements >- methyliodopropylammonium ), 0 ° c >< sub >< melting point depression higher melting entropy atomic thermal vibrations ></ sub >. ></ sub >) markedly modulates glass based hybrid perovskites showing increased glass ionic sn – mc3i )< sub forming ability relative free melt processing relatively lower glass 4 </ sub 2 </ sub ></ sub forming ability melting transition thermal behavior increased lone 2 k glass formation based systems based system forming propensity forming abilities reduced tolerance ray diffraction molten state mechanistic origins enabling solvent dependent single crystal x compositional design 50 crystal 100 k Two-dimensional organic–inorganic perovskites can attain lower congruent melting temperatures (<i>T</i>_<i>m</i>) through compositional design, including, for example, by incorporating nonprimary ammonium cations, enabling solvent-free melt processing and glass formation. Although Pb- and Sn-based systems have been explored, the structural and mechanistic origins of their distinct thermal behaviors remain poorly understood. Here, starting from the model (MC3I)₂PbI₄ (MC3I = <i>N</i>-methyliodopropylammonium), we demonstrate that replacing Pb with Sn lowers <i>T</i>_<i>m</i> to 86.0 °C (359.2 K) and markedly modulates glass-forming ability. Temperature-dependent single-crystal X-ray diffraction, pair distribution function, and first-principles electron localization functions provide continuous structural insights from 100 K to the molten state, enabling direct comparison across the melting transition and correlation with thermal behavior. We demonstrate that Sn substitution yields larger structural distortions (e.g., associated with increased lone-pair stereoactivity), selectively elongated and more ionic Sn–I bonds, reduced tolerance for atomic thermal vibrations, and more accessible atomic arrangements in the melt, resulting in a higher melting entropy (Δ<i>S</i>_<i>m</i>) and lower <i>T</i>_<i>m</i>. Both Pb and Sn compounds exhibit robust melt stability over 50 crystal-melt-glass cycles without discernible decomposition, while showing increased glass-forming propensity. Prolonged melt dwelling effectively promotes vitrification in the Sn compound, despite its relatively lower glass-forming ability relative to the Pb-based system. 2026-09-30T00:00:00Z Text Journal contribution 10.1021/acs.chemmater.6c01289.s001 https://figshare.com/articles/journal_contribution/Melting_Point_Depression_and_Glass-Forming_Abilities_in_Pb-_and_Sn-Based_Hybrid_Perovskites_with_a_Nonprimary_Ammonium_Cation/34033696 CC BY-NC 4.0