Related Experiment Video
Updated: Oct 19, 2025
09:33
Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch
Published on: February 7, 2022
3.6K
A Tri-state Fluorescent Switch with "Gated" Solid-state Photochromism Induced by an External Force
Chen Qian1, Zhimin Ma2, Jianwei Liu1
1Beijing State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, P. R. China.
Chemistry, an Asian Journal
|September 17, 2021
Summary
Researchers developed a new molecule exhibiting aggregation-induced emission enhancement (AIEE), mechanochromism, and photochromism. Mechanical force triggers fluorescence changes and a reversible photochromic effect, enabling novel encryption applications.
Area of Science:
- Materials Science
- Organic Chemistry
- Photochemistry
Background:
- Aggregation-induced emission enhancement (AIEE) materials are crucial for advanced optical applications.
- Mechanochromism and photochromism offer dynamic responses to external stimuli.
- Developing stimuli-responsive molecules is key for innovative technologies.
Purpose of the Study:
- To design and synthesize a novel molecule combining dihydroazulene (DHA) and phenothiazine (PTZ) moieties.
- To investigate the molecule's aggregation-induced emission enhancement (AIEE) properties.
- To explore its mechanochromic and photochromic behaviors under external force and light.
Main Methods:
- Synthesis of a novel DHA-PTZ molecule.
- Characterization of photophysical properties including fluorescence and absorption spectra.
- Mechanical stimulation (grinding) to induce mechanochromism.
- Photochromic studies on the mechanically stimulated material.
- Time-dependent density functional theory (TD-DFT) calculations.
Main Results:
- The synthesized molecule exhibits AIEE, mechanochromism, and gated solid-state photochromism.
- Grinding induced a red-shift in fluorescence from 570 nm to 600 nm by loosening intermolecular interactions.
- Mechanical force activated DHA ring-opening, leading to photochromism with fluorescence quenching and a new absorption band at 470 nm.
- TD-DFT revealed a shift from intramolecular charge-transfer (ICT) to locally excited (LE) emission.
Conclusions:
- The novel DHA-PTZ molecule demonstrates significant mechanochromic and photochromic responses.
- The observed phenomena are attributed to changes in intermolecular interactions and electronic transitions.
- The molecule's unique properties pave the way for developing advanced encryption systems.
