Nano-Trap Engineering in MOF Microenvironment for Ultratrace Iodine Sensors

TL;DR

This paper presents a novel MOF-based sensor with ultra-trace iodine detection capabilities, achieving high sensitivity, selectivity, and fast response times suitable for nuclear safety applications.

Contribution

The study introduces a rationally designed hydrophobic MOF with enhanced electrical response for ultra-trace iodine sensing, including detailed atomic-level analysis and scalable fabrication methods.

Findings

Achieved nearly billion-fold increase in electrical response.

Demonstrated high selectivity and ppb-level sensitivity in demanding environments.

Identified optimal MOF layer thickness for industrial sensor deployment.

Abstract

Ultra-sensitive and highly selective iodine gas sensors play a crucial role during the nuclear radiation leak for a timely detection and mitigation of pollution, ensuring the safety of a vast number of operators and subsequent integrity of the facility. Herein, we rationally designed a metal-organic framework (MOF) that exhibits an outstanding performance with an almost billion-fold enhancement in the electrical response due to its optimized hydrophobicity, which allows the easy migration of iodine molecules though the channels and the presence of suitable interaction sites, temporarily anchoring the target molecule for ultra-trace sensing. The prototype sensor tested in demanding environments demonstrates its high selectivity, ultra-trace parts per billion (ppb)-level sensitivity, good reversibility, and a very fast response time even at high frequencies compared to existing adsorbents, including commercially available materials. Further, the iodine sensing at the atomic level was studied in detail by measuring the electrical response of a single crystal and, the optimal thickness of the MOF layer was identified for an industrially-viable prototype sensor by using inkjet printing. In a wider perspective, we propose a general strategy towards electrically efficient sensing materials with hybrid functionalities for engineering high-sensitivity iodine sensors for a safe and sustainable future.