Fluorinated Iron and Cobalt Phthalocyanine Nanowire Chemiresistors for Environmental Gas Monitoring at Parts-per-Billion Levels

Abstract

Herein, a single-step production for the development of gas sensing devices from unsubstituted and hexadecafluorinated metal phthalocyanines (MPc, M = Fe2+ and Co2+) is explained. The preparation of sensor devices by the direct growth of nanowires on interdigitated electrodes by the vapor transport of the synthesized MPc precursors is discussed, emphasizing a single-step approach. Results using as-prepared devices for the detection of NH3 and NO2 in the ppb range are shown. In agreement with similar MPc sensing materials, response and recovery times fitted using a double-exponential model gave two rate constants: a short one, on the order of minutes for concentrations above 500 ppb, and a long one, on the order of hours. These rate constants are suitable for environmental monitoring of gases in recovery zones, where longer exposure times are critical in the sampling process. Our F16FePc-NW sensor prototypes show a ∼10% normalized response toward NH3 at 40 ppb for a measuring time of ∼2.5 h at room temperature and measurable responses to concentrations as low as 5 ppb, rendering them applicable to environmental studies.

Development of Highly Sensitive and Humidity Independent Room Temeprature NO2 Gas Sensor Using Two Dimensional Ti3C2Tx Nanosheets and One Dimensional WO3 Nanorods Nanocomposite

“…The main prerequisite for a typical room temperature sensor are high sensitivity and selectivity, fast response/recovery time, low detection limit, and reversibility even under high humidity and low temperature. Different materials including organic molecules, conducting polymer, metal oxides, two dimensional carbonaceous materials, − and transition metal dichalcogenides/carbide , have been explored in gas sensing applications. Among these materials, metal oxides have been widely investigated for monitoring different toxic gases due to their outstanding properties such as wide band gap, intrinsic oxygen vacancies, and high chemical, as well as thermal stability and an environmental friendly nature .…”

Automation and Computerization of (Bio)sensing Systems

“…Other Prototypes of Automated Sensing Systems. Sensor prototypes can help to address analytical challenges in various fields, which include agriculture and soil analysis, 122 clinical diagnostics, 123 environmental gas monitoring, 124 healthcare monitoring, 125 environmental monitoring, 126 water quality monitoring, 127 food safety and quality control, 128 and air pollution monitoring. 129 For instance, Yang et al developed an autonomous sensing boat for on-site heavy metal detection in natural waters utilizing square-wave anodic stripping voltammetry, which can circumvent the need for off-site costly laboratory detection and the time-consuming operations conducted by trained personnel (Figure 4-I-A−C).…”

Palladium Phthalocyanine Nanowire-Based Highly Sensitive Sensors for NO2(g) Detection

“…In the last decade, MPcs have been used as key materials to develop novel sensitive chemiresistors for a variety of analytes. They are particularly attractive for gas sensing because their sensitivity and response toward various analytes can be tailored by (i) the nature of the central metal atom and (ii) the substituents in the aromatic rings [ 7 , 8 ]. MPcs are macrocyclic organic compounds with a conjugated planar structure composed of 18 π-electrons that are responsible for interactions with incoming gases that result in sensing responses [ 7 , 8 ].…”