Reconstructive Phase Transition Enables Abnormal Negative Thermal Quenching of Photoluminescence in a 1D Hybrid Perovskite

Organic-inorganic hybrid perovskites (OIHPs) have attracted enormous attention owing to their intriguing structural tunability and diverse functional properties. Reconstructive phase transitions, involving the breaking and reconstruction of chemical bonds, have rarely been found in such materials; however, these features may induce many intriguing physical properties in optics, ferroelectrics, ferromagnetics, and so forth. Here, we utilized the weak and switchable coordination bonds of HETMA-MnCl₃ (HETMA = (2-hydroxyethyl) trimethylammonium) to construct a 1D hybrid perovskite employing a neutral framework. As expected, this compound undergoes a reconstructive phase transition with a high phase transition temperature of 421 K. HETMA-MnCl₃ shows remarkable red fluorescence, a wide emission spectrum, and a long luminous lifetime. Impressively, the reconstructive phase transition of HETMA-MnCl₃ dominates the excellent PL coexistence of negative thermal quenching and thermal quenching behavior. To the best of our knowledge, such a phenomenon has rarely been found in the realm of multifunctional optoelectronic materials. This work provides possibilities to explore new classes of perovskite materials with reconstructive phase transitions and contributes to further developments.