Electroactive Organic Cage as Efficient Adsorbent and Ultrasensitive Transistor Sensor for Trace Iodine

Area of Science:

• Materials Science
• Environmental Chemistry
• Nanotechnology

Background:

• Efficient capture and detection of radioiodine from nuclear waste and contaminated water are critical for environmental safety.
• Simultaneously achieving high-performance adsorption and ultrasensitive detection with a single material for iodine (I2) remains a significant challenge.
• Existing methods for iodine detection often lack the sensitivity required for trace amounts in environmental samples.

Purpose of the Study:

• To develop a single material capable of both efficient iodine (I2) capture and ultrasensitive detection.
• To investigate the performance of a tetrathiafulvalene (TTF)-decorated organic cage (TTFcage) as an adsorbent and sensor for iodine.
• To demonstrate the potential for integrated on-site treatment and monitoring of radioiodine contamination.

Main Methods:

• Synthesis and characterization of a tetrathiafulvalene (TTF)-decorated organic cage (TTFcage).
• Evaluation of TTFcage as an adsorbent for iodine (I2) vapor and in contaminated water.
• Fabrication and testing of a cage-based organic field-effect transistor (cOFET) sensor utilizing TTFcage for iodine detection.

Main Results:

• TTFcage exhibited an ultrahigh I2 vapor uptake of 1.28 g g⁻¹, significantly exceeding industrial silver adsorbents.
• The material effectively decontaminated iodine in flowing water to below WHO criteria (<0.1 ppm) with a capacity of 5.16 g g⁻¹.
• The developed cOFET sensor achieved an unprecedented limit of detection (LoD) for I2 as low as 0.58 ppt (≈10⁻¹² M), six orders of magnitude better than spectroscopic methods.

Conclusions:

• The TTFcage material demonstrates exceptional performance for both iodine (I2) adsorption and ultrasensitive detection.
• The integrated adsorption-detection capabilities on a miniaturized chip offer a portable solution for on-site environmental monitoring and remediation.
• This work presents a novel approach for tackling radioiodine pollution challenges in nuclear waste management and water safety.