image: Dual-modal (pressure- and DMF-triggered) fluorescence switch.
Credit: ©Science China Press
A research team from Jilin University has developed a zero-dimensional hybrid metal halide, C13N2H16SbCl5 ([BPP]SbCl5), that exhibits reversible fluorescence switching under both pressure and solvent stimulation. Published in Science Bulletin, the work demonstrates how the material can be toggled between non‑emissive and highly emissive states, paving the way for multifunctional optical applications in sensing, anti‑counterfeiting, and adaptive photonic systems.
Conventional optical‑response materials often suffer from single‑mode responsiveness and irreversible signal loss, limiting their practical use. Zero‑dimensional metal halides, with their soft crystalline frameworks and confined electronic structures, offer a promising platform for building reversible, multi‑stimuli optical switches.
In this study, [BPP]SbCl5 shows two distinct activation pathways. Under ambient conditions, the material is non‑emissive due to concentration‑caused quenching. When compressed to about 7.4 GPa, it undergoes a monoclinic‑to‑triclinic phase transition. The resulting lattice distortion enhances electron‑phonon coupling, activating broad orange emission from self‑trapped excitons. The emission intensity grows steadily with further compression up to 23.0 GPa.
Simultaneously, the material displays a highly selective response to the solvent DMF (N,N‑dimethylformamide). Upon DMF exposure, it rapidly turns into a bright yellow emitter with a photoluminescence quantum yield of 97%—a near‑unity efficiency. This “ON” state can be completely reversed by gentle heating, which removes the DMF and restores the non‑emissive phase. The solvent‑induced switching shows outstanding cyclability, with over 10 reversible cycles without performance degradation.
The dual‑response capability was harnessed in several practical demonstrations. The team constructed an ultrasensitive DMF‑detection platform, a multi‑level optical anti‑counterfeiting system where information is revealed by DMF and erased by heat, and a reconfigurable optical logic gate that performs the operation A + B·C′. These examples highlight the material’s potential for smart sensing, dynamic information encryption, and programmable optical computing.
Mechanistic investigations linked the emission switching to pressure‑ and solvent‑driven structural distortions, which modulate exciton localization and enhance radiative recombination. The work not only advances the understanding of stimulus‑response processes in low‑dimensional metal halides but also provides a design strategy for creating adaptive optical materials with tailored functionalities.
The study was conducted by Jingtian Wang, Xihan Yu, Kai Wang, Guanjun Xiao, and Bo Zou. Corresponding author is Guanjun Xiao (xguanjun@jlu.edu.cn). The research was published in Science Bulletin and supported by the National Key R&D Program of China, the National Natural Science Foundation of China and the synchrotron radiation facility at beamline BL15U1 of the Shanghai Synchrotron Radiation Facility.