Reversible Three-Color Fluorescence Switching of an Organic Molecule in the Solid State via "Pump-Trigger" Optical...

Area of Science:

• Materials Science
• Photochemistry
• Nanotechnology

Background:

• Photoswitches often exhibit unstable fluorescence due to simultaneous photoluminescence and photoisomerization under UV light.
• Achieving stable and controllable multi-color fluorescence switching in solid-state photoswitches remains a challenge.

Purpose of the Study:

• To demonstrate reversible solid-state triple fluorescence switching using "Pump-Trigger" multiphoton manipulation.
• To develop a novel fluorescence photoswitch capable of emitting distinct colors (green, yellow, red) with high stability.
• To explore applications in advanced imaging techniques like tunable cell imaging and super-resolution microscopy.

Main Methods:

• Development of a novel photoswitch molecule, BOSA-SP, incorporating a spiropyran (SP) moiety.
• Utilizing "Pump-Trigger" multiphoton excitation to induce distinct photoexcitation and photoisomerization processes.
• Leveraging the non-overlapping energy ranges of photoexcitation and photoisomerization for controlled switching.
• Exploiting the large free volume within the solid-state SP moiety to enhance reversible photoisomerization.

Main Results:

• Successfully achieved reversible solid-state triple fluorescence switching (green, yellow, red) with the BOSA-SP photoswitch.
• Demonstrated that the energy ranges for photoexcitation and photoisomerization do not overlap, ensuring controlled switching.
• Confirmed that the solid-state SP moiety's free volume promotes efficient reversible photoisomerization.
• Successfully applied reversible dual-fluorescence switching for two-color super-resolution imaging.

Conclusions:

• The "Pump-Trigger" multiphoton manipulation strategy enables stable, programmable, and multi-color fluorescence switching in solid-state photoswitches.
• BOSA-SP offers a versatile platform for advanced optical imaging, including tunable cell imaging and super-resolution microscopy.
• This work overcomes limitations of conventional photoswitches, paving the way for new applications in materials science and nanotechnology.