Unprecedented 30 K hysteresis across switchable dielectric and magnetic properties in a bright luminescent organic–inorganic halide (CH6N3)2MnCl4

Abstract

Multifunctional materials that exhibit various switchable properties and simultaneously feature excellent luminescent properties boast tremendous technological importance. However, realization of such materials is still elusive, as integration of these independent yet technologically important properties in single materials is fairly challenging. Here, we report a new highly photoluminescent hybrid (CH₆N₃)₂MnCl₄ (CH₆N₃ = guanidinium cation, GC) that exhibits an unprecedented 30 K wide hysteresis in dielectric and magnetic switching across the structural phase transition (SPT). The compound uniquely features trimeric (Mn₃Cl₁₂)⁶⁻ units composed of face-sharing MnCl₆ octahedra in its zero-dimensional crystal structure and undergoes a thermally induced reversible structural transition at 166/195 K. The high and low dielectric states show a remarkable 30 K wide reversible dielectric switching which is mainly portrayed by the relative population of quadrupolar and dipolar moments of disordered and ordered phases of GCs. Only a small change in the crystal volume across the transition is reflected in subtle magnetic switching. Moreover, the material exhibits an intense orange–red emission under ultraviolet excitation at room temperature with long lifetime (1.71 ms) and large quantum yield (39.5%). This report suggests a promising strategy to construct truly multifunctional optoelectronic materials and may be helpful to improve the understanding and control of switchable physical properties and luminescence in supramolecular materials.