Coordination Trap Induced Structural and Luminescent Property Transformation of Low Dimensional Organic-Inorganic Hybrid Perovskites

Herein, a coordination trap strategy is proposed for constructing stimulus-responsive phosphorescent perovskites. Hydroxyl groups are selected as trap groups and introduced into benzylamine hydrochloride of Cd-based perovskite. The resulting two-dimensional (2D) perovskite (C7H10NO)2CdCl4 & BULL;H2O (H1) exhibits blue fluorescence at 405 nm and green phosphorescence at 482 nm under 365 nm excitation. After introducing guest Mn2+, due to the passivation of defects, the doped H1 (H1-M) achieves orange phosphorescence (& lambda; = 615 nm) of Cd2+. Interestingly, because thermal stimulation induces the coordination of hydroxyl groups with metal ions, H1 and H1-M are transformed into the zero-dimensional (0D) perovskite (C7H10NO)2CdCl4 (H2) and doped H2 (H2-M), respectively. The coordination immobilizes the organic molecules, thus resulting in a large increase in the phosphorescence lifetime and a strong green afterglow of H2. The coordination also transforms the luminescent center of the doped perovskite from the host metal ion of H1-M to the guest metal ion of H2-M, achieving red phosphorescence of Mn2+ at 685 nm. Under water vapor, H2 and H2-M are reversibly converted to H1 and H1-M, respectively. Based on the above phenomena, a multilevel anti-counterfeit encryption system with water/heat stimulus-response is developed, which provides a new idea for the design of stimulus-responsive phosphorescent intelligent materials. Under external stimulation, perovskites with trap groups can induce coordination between ligands and metal ions, thus leading to a structure transition from 2D to 0D and luminescence centers altering from the host metal ions to the guest ones.image

Automated summary

A coordination trap strategy is proposed to construct stimulus-responsive phosphorescent perovskites. Hydroxyl groups are selected as trap groups and introduced into Cd-based perovskite. The trapping and releasing of ligands by the metal ions induces structure transition and alters the luminescence center, providing a new idea for the design of stimulus-responsive phosphorescent intelligent materials.