Universal Strategy for Improving the Sensitivity of Detecting Volatile Organic Compounds by Patterned Arrays

Abstract

The diffusion of target analytes is a determining factor for the sensitivity of a given gas sensor. Surface adsorption results in a low‐concentration region near the sensor surface, producing a concentration gradient perpendicular to the surface, and drives a net flux of molecules toward solid reactive reagents on the sensor surface, that is, vertical diffusion. Here, organic semiconductor supramolecules were patterned into micromeshed arrays to integrate vertical and horizontal diffusion pathways. When used as a gas sensor, these arrays have an order of magnitude higher sensitivity than traditional film‐based sensors. The sensor sensitivity ramp down with the increase in coverage density of reactive reagents, yielding two linear regions demarcated by 0.3 coverage, which are identified by the experimental results and simulations. The universal nature of template‐assisted patterning allows adjustments in the composition, size, and shape of the constituent material, including nanofibers, nanoparticles, and molecules, and thus serves to improve the sensitivity of gas sensors for detecting various volatile organic compounds.

Nanoassembled Interface for Dynamics Tailoring

“…In addition to the above-mentioned systems, we most recently developed a patterned array to tailor the gaseous molecular diffusion at the solid−gas interface (Figure 5G− H). 41 Traditional film-based sensors adsorb gaseous targets depending only on the concentration gradient induced vertical diffusion, leading to a low-speed reaction. However, while the gas sensors were constructed as patterned, micromesh arrays, a horizontal concentration gradient was created (Figure 5H).…”

“…(J–L) Simulation of gas velocity at the interface of different arrays. Reproduced with permission from ref . Copyright 2020 Wiley-VCH.…”

Film Nanoarchitectonics of Pillar[5]arene for High-Performance Fluorescent Sensing: a Proof-of-Concept Study

“…1−5 It has found broad applications in the detection of various hazardous chemicals, such as explosives, 6 illicit drugs, 2 formaldehyde, 7,8 and other important volatile organic compounds (VOCs). 9,10 The performance of a fluorescent film sensor is highly dependent on the property of the sensing film employed, which consists of two key components: sensing unit and substrate. 11−13 Therefore, innovation of the sensing unit is a key point in the development of high-performance sensing films as it not only reports signals but also determines the effectiveness of a sensing process.…”

“…Film-based fluorescence sensing plays an irreplaceable role in the sensing filed due to its distinct advantages over solution-based one, such as portable, reusable, real-time, and noninvasion detection, etc. − It has found broad applications in the detection of various hazardous chemicals, such as explosives, illicit drugs, formaldehyde, , and other important volatile organic compounds (VOCs). , The performance of a fluorescent film sensor is highly dependent on the property of the sensing film employed, which consists of two key components: sensing unit and substrate. − Therefore, innovation of the sensing unit is a key point in the development of high-performance sensing films as it not only reports signals but also determines the effectiveness of a sensing process . The substrate also plays a critical role since it could affect the sensing performance of the film through modulating the mass transfer efficiency of the analyte molecules via alternating the fluorescent adlayer structure …”

Highly improved performance of a film-based fluorescent sensor via a nanomesh scaffold strategy

“…Notably, the nanomesh scaffold modified sensor can sense biomarker of anthrax spores (2,PDA), which is a highly lethal agent to human beings and animals and also potential biological warfare agents 14 . The nanomesh scaffold modified sensor has a significant response to saturated vapor of PDA (c PDA = 2.8 ppt), and the response intensity is seven times stronger than the ground glass-based sensor (inset of Fig.…”