Hybrid Photonic Cavity with Metal-Organic Framework Coatings for the Ultra-Sensitive Detection of Volatile Organic Compounds with High Immunity to Humidity

Jifang Tao,Tao Sun,Yuandong Gu,Dan Zhao,Tong Lin,Xuerui Wang,Yuxiang Wang,Dongliang Fu,Hong Cai,Lennon Lee Yao Ting

doi:10.1038/srep41640

Abstract

Detection of volatile organic compounds (VOCs) at parts-per-billion (ppb) level is one of the most challenging tasks for miniature gas sensors because of the high requirement on sensitivity and the possible interference from moisture. Herein, for the first time, we present a novel platform based on a hybrid photonic cavity with metal-organic framework (MOF) coatings for VOCs detection. We have fabricated a compact gas sensor with detection limitation ranging from 29 to 99 ppb for various VOCs including styrene, toluene, benzene, propylene and methanol. Compared to the photonic cavity without coating, the MOF-coated solution exhibits a sensitivity enhancement factor up to 1000. The present results have demonstrated great potential of MOF-coated photonic resonators in miniaturized gas sensing applications.

Highlights

Volatile organic compounds (VOCs), such as xylene, benzene, and formaldehyde, are those chemicals with high vapor pressures at room temperature
Dramatically increased amount of gas molecules can be adsorbed by the metal-organic framework (MOF) coating of the waveguides, leading to an obvious resonance shift (ΓΔλ) of the micro-ring that can be detected with increased detection sensitivity (Fig. 1b)
The reversible and marginal water uptake endows ZIF-8 the merits of high immunity to humidity, and preserve the ZIF-8 based sensor from moisture attack, while cross-responding to humidity is regarded as one of most challenges for gas sensors

Summary

Introduction

Volatile organic compounds (VOCs), such as xylene, benzene, and formaldehyde, are those chemicals with high vapor pressures at room temperature. Some other compact gas-phase VOCs sensors based on nanocantilevers[13], graphane[14,15] or carbon nano-tubes[16,17] were demonstrated with very high sensitivity and fast response, but their sensitivity drifts seriously in long time running and they are unstable to be used in real test conditions due to strong cross-response to humidity[18] Another alternative technology for VOCs sensing is absorption spectroscopy, which measures the optical power variation in photon-gas interaction and have unique advantages such as low cross-response, fast response and high accuracy[19,20].

Methods

Results

Conclusion