Component/Stimulus-Dependent Multi-Exciton Emission in Zr(IV)-Based Organic Metal Halides Triggered by Supramolecular Assembly and Antimony Doping

Abstract

Recently, Sb³⁺-activated 0D Zr(IV)-based metal halides have gained enormous attention for their unique optical properties. However, realizing efficient white emission and multiple reversible emissions in a single system remains a great challenge. Parallelly, the currently reported Sb³⁺-activated Zr(IV)-based organic metal halides are mainly through aimless regulation of the type of A-site organic cations, severely limiting their development. Herein, all-inorganic Cs₂ZrCl₆:Sb³⁺ is employed as the conformational model, three different compounds of Sb³⁺-doped [18-crown-6@A]₂ZrCl₆ (A = K, Rb, Cs) are developed via supramolecular assembly. All compounds show efficient tunable white emission with luminous efficiency of 91.28% for [18-crown-6@K]₂ZrCl₆:Sb³⁺, 84.84% for [18-crown-6@Rb]₂ZrCl₆:Sb³⁺, and 78.63% for [18-crown-6@Cs]₂ZrCl₆:Sb³⁺, which shall stem from Sb³⁺-induced multi-exciton emission in [SbCl₆]³⁻ octahedron. Particularly, the strong supramolecular interaction can enhance the structural rigidity and suppress nonradiative transitions, which is the dominated reason for [18-crown-6@A]₂ZrCl₆:Sb³⁺ exhibits efficient emission. The component/excitation/temperature/moisture-dependent multiple reversible PL switching characteristics are observed in Sb³⁺-doped [18-crown-6@A]₂ZrCl₆, which allows to demonstrate their applications in advanced optical anti-counterfeiting and information encryption. Moreover, a single-component white light-emitting diode is also fabricated, which shows a high color rendering index of 96.1. Therefore, the work provides a feasible scheme for designing organic Zr(IV) halides with fascinating optical properties.