Radiochromic Hydrogen-Bonded Organic Frameworks for X-ray Detection

Area of Science:

• Materials Science
• Chemistry
• Radiation Detection

Background:

• Porous materials are explored for photochromic radiation detection.
• Hydrogen bonded organic frameworks (HOFs) have not been utilized in this area.
• Developing novel radiochromic materials is crucial for safety and monitoring.

Purpose of the Study:

• To synthesize and characterize new HOFs for radiochromic applications.
• To investigate the radiochromic response of HOFs to X-ray and UV irradiation.
• To understand the factors controlling radiochromic specificity in HOFs.

Main Methods:

• Synthesis of two HOFs (PFC-25, PFC-26) via self-assembly of a tetratopic viologen ligand and formic acid.
• Experimental and theoretical studies to analyze radiochromic behaviors and mechanistic understanding.
• Fabrication of PFC-25 into a portable naked-eye sensor.

Main Results:

• PFC-26 responds to both X-ray and UV light; PFC-25 responds only to X-rays.
• The degree of π-conjugation in the viologen ligand influences charge transfer and radiochromic specificity.
• PFC-25 demonstrates a reproducible X-ray dose threshold of 3.5 Gy with high transmittance contrast and stability.

Conclusions:

• HOFs represent a new class of "all-organic" radiochromic smart materials.
• Viologen ligand's π-conjugation is key for specific radiation detection.
• PFC-25 shows potential as a practical, portable X-ray sensor.