Stepwise Crystalline Structural Transformation in 0D Hybrid Antimony Halides with Triplet Turn-on and Color-Adjustable Luminescence Switching

Abstract

Intelligent stimuli-responsive fluorescence materials are extremely pivotal for fabricating luminescent turn-on switching in solid-state photonic integration technology, but it remains a challenging objective for typical 3-dimensional (3D) perovskite nanocrystals. Herein, by fine-tuning the accumulation modes of metal halide components to dynamically control the carrier characteristics, a novel triple-mode photoluminescence (PL) switching was realized in 0D metal halide through stepwise single-crystal to single-crystal (SC-SC) transformation. Specifically, a family of 0D hybrid antimony halides was designed to exhibit three distinct types of PL performance including nonluminescent [Ph₃EtP]₂Sb₂Cl₈ (1), yellow-emissive [Ph₃EtP]₂SbCl₅·EtOH (2), and red-emissive [Ph₃EtP]₂SbCl₅ (3). Upon stimulus of ethanol, 1 was successfully converted to 2 through SC-SC transformation with enhanced PL quantum yield from ~0% to 91.50% acting as "turn-on" luminescent switching. Meanwhile, reversible SC-SC and luminescence transformation between 2 and 3 can be also achieved in the ethanol impregnation-heating process as luminescence vapochromism switching. As a consequence, a new triple-model turn-on and color-adjustable luminescent switching of off-on^I-on^II was realized in 0D hybrid halides. Simultaneously, wide advanced applications were also achieved in anti-counterfeiting, information security, and optical logic gates. This novel photon engineering strategy is expected to deepen the understanding of dynamic PL switching mechanism and guide development of new smart luminescence materials in cutting-edge optical switchable device.

Fig. 1.

Crystal structures of compounds 1 (A), 2 (B), and 3 (C); photo-images of single crystals under sunlight and 365 nm UV light, as well as Commission Internationale de l’Eclairage (CIE) chromaticity coordinates for compounds 1 (D), 2 (E), and 3 (F); solid-state UV–Vis absorption; and PLE and PL spectra of compounds 1 (G), 2 (H), and 3 (I) at 300 K.

Fig. 2.

PL property characterizations of compounds 2 and 3: PL decay curve of 2 (A), 3D PL consecutive map of 2 (B), excitation wavelength-dependent PL spectra of 2 (C), excitation power-dependent PL emission intensity of 2 (D), temperature-dependent PL emission spectra of 2 (E), experimental and fitted temperature-dependent FWHM of 2 (F), PL decay curve of 3 (G), temperature-dependent PL emission spectra of 3 (H), and experimental and fitted temperature-dependent FWHM of 3 (I).

Fig. 3.

Optimized geometries of [SbCl₅]²⁻ units at ground state and excited state for compounds 2 (A) and 3 (B), and proposed PL mechanism in configuration coordination diagram of compounds 2 (C) and 3 (D).

Fig. 4.

Evolution of photo-images in EtOH solvent (A) and in situ PL emission spectra (B) showing the PL transformation from 1 to 2; evolution of photo-images (C) and in situ PL emission spectra (D) in the reversible PL transformation between 2 and 3 under heating and EtOH trigger; the PL emission intensity during the cycle of EtOH impregnation and heating treatment as a function of cycle number (E); transition of CIE chromaticity coordinates among 1, 2, and 3 (F).

Fig. 5.

Anti-counterfeiting and information encryption–decryption applications: photo-image transitions of luminescence security patterns under 365 nm UV light irradiation (A) and schematic diagram of information encryption–decryption process in luminescence security pattern based on combined compounds 1, 2, and 3 (B).

Fig. 6.

Optical logic gate applications: illustration of the binary optical logic gates based on compound 1 (A), 2 (B), and 3 (C); definition of inputs and outputs (D); and truth tables of 2-input and 2-output logic gates and schemes (E and F).