Highly sensitive X-ray responsive molecular switches

Area of Science:

• Materials Science
• Chemistry
• Physics

Background:

• Existing X-ray-triggered molecular switches require high doses, limiting their practical application.
• Remote control of molecular functions behind physical barriers remains a challenge.

Purpose of the Study:

• To develop a low-dose X-ray-triggered molecular switching system.
• To enable remote control of molecular functions in complex environments.
• To achieve high-resolution X-ray imaging with molecular switches.

Main Methods:

• Utilizing triplet-triplet energy transfer (TTET) from a scintillator to a photoswitch.
• Designing flexible films with a Cu2I2(POP)2 scintillator and a hydrazone switch.
• Employing HPLC, radical-scavenger tests, and time-resolved spectroscopy to elucidate the mechanism.

Main Results:

• Achieved photoswitching at ~0.18 Gy, two orders of magnitude lower than previous systems.
• Demonstrated a detection limit near 0.01 mGy.
• Established a design rule for TTET based on triplet-level matching.
• Enabled high-resolution radiography (3251 dpi) with long-term pattern retention (≥2 months).

Conclusions:

• X-ray energy can be efficiently routed through triplet excitons for low-dose molecular switching.
• This approach offers practical control of molecular functions in previously inaccessible environments.
• The developed system provides a sensitive and high-resolution platform for X-ray imaging and molecular control.