scholarly journals Atmospheric Photoionization Detector with Improved Photon Efficiency: A Proof of Concept for Application of a Nanolayer Thin-Film Electrode

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7738
Author(s):  
Adelaide Miranda ◽  
Pieter A. A. De Beule
Keyword(s):  
Thin Film ◽  
Vacuum Ultraviolet ◽  
Gas Sensing ◽  
Ambient Air ◽  
Low Pressure ◽  
Hydrocarbon Contamination ◽  
Ionization Mechanism ◽  
Metal Grid ◽  
Photoionization Detector ◽  
Hygroscopic Nature

Atmospheric photoionization is a widely applied soft ionization mechanism in gas sensing devices for the detection of volatile organic compounds in ambient air. Photoionization is typically induced by low-pressure Vacuum Ultraviolet (VUV) lamps with MgF2 or LiF lamp surface windows depending on the gas fill and the required wavelength transmission window. These lamps are known to exhibit gradually reduced VUV transmission due to hydrocarbon contamination. LiF surface windows are known to be especially problematic due to their hygroscopic nature, reducing VUV lamp lifetime to a mere 100 h, approximately. Here, we present a new design for the electrode of a photoionization detector based on thin-film technology. By replacing the commonplace metal grid electrode’s VUV lamp surface window with a chromium/gold thin film we obtain a doubling of photon efficiency for photoionization. Replacing the hygroscopic LiF lamp window surface with a metallic layer additionally offers the possibility to vastly increase operational lifetime of low-pressure Argon VUV lamps.

Silicon Microhotplate Arrays as a Platform for Efficient Gas Sensing Thin Film Research

1996 ◽  
Vol 444 ◽  
Author(s):  
F. Dimeo ◽  
S. Semancik ◽  
R. E. Cavicchi ◽  
J. S. Suehle ◽  
N. H. Tea ◽  
...  
Keyword(s):  
Thin Film ◽  
Gas Sensing ◽  
Film Research

Abstract

Fouling Is the Beginning: Upcycling Biopolymer-Fouled Substrates for Fabricating High-Permeance Thin-Film Composite Polyamide Membranes

2020 ◽  
Author(s):  
Ruobin Dai ◽  
Hongyi Han ◽  
Tianlin Wang ◽  
Jiayi Li ◽  
Chuyang Y. Tang ◽  
...  
Keyword(s):  
Thin Film ◽  
High Pressure ◽  
End Of Life ◽  
Water Purification ◽  
Low Pressure ◽  
Polymeric Membranes ◽  
Membrane Recycling ◽  
Film Composite ◽  
Thin Film Composite ◽  
First Time

Commercial polymeric membranes are generally recognized to have low sustainability as membranes need to be replaced and abandoned after reaching the end of their life. At present, only techniques for downcycling end-of-life high-pressure membranes are available. For the first time, this study paves the way for upcycling fouled/end-of-life low-pressure membranes to fabricate new high-pressure membranes for water purification, forming a closed eco-loop of membrane recycling with significantly improved sustainability.

Study of Thin Film Tin Oxide for Reliability as Gas Sensing Material

2020 ◽  
Author(s):  
Ravi Shankar ◽  
Tien Choy Loh ◽  
Le Khaing Le ◽  
Chun Wei Khor ◽  
Shian Yeu Kam ◽  
...  
Keyword(s):  
Thin Film ◽  
Tin Oxide ◽  
Gas Sensing ◽  
Sensing Material

Low pressure high flux thin film nanofibrous composite membranes prepared by electrospraying technique combined with solution treatment

2012 ◽  
Vol 394-395 ◽  
pp. 241-247 ◽  
Author(s):  
Hao You ◽  
Yin Yang ◽  
Xiong Li ◽  
Kai Zhang ◽  
Xuefen Wang ◽  
...  
Keyword(s):  
Thin Film ◽  
Solution Treatment ◽  
Composite Membranes ◽  
Low Pressure ◽  
High Flux

Effect of Temperature on the Electrical and Gas Sensing Properties of Polyaniline and Multiwall Carbon Nanotube Doped Polyaniline Composite Thin Films

2011 ◽  
Vol 254 ◽  
pp. 167-170 ◽  
Author(s):  
Subodh Srivastava ◽  
Sumit Kumar ◽  
Vipin Kumar Jain ◽  
Y.K. Vijay
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Gas Sensing ◽  
Hydrogen Gas ◽  
Composite Thin Film ◽  
Effect Of Temperature ◽  
Multiwall Carbon Nanotube ◽  
Film Sensor ◽  
Composite Thin Films ◽  
Pani Composite

In the present work we have reported the effect of temperature on the gas sensing properties of pure Polyaniline (PANI) and Multiwall carbon nanotube (MWNT) doped PANI composite thin film based chemiresistor type gas sensors for hydrogen gas sensing application. PANI and MWNT doped PANI composite were synthesized by in situ chemical oxidative polymerization of aniline using ammonium persulfate in an acidic medium. The thin sensing film of chemically synthesized PANI and MWNT doped PANI composite were deposited onto finger type Cu-interdigited electrodes using spin cast technique to prepared chemiresistor type gas sensor. The electrical properties of these composite thin films were characterized by I-V measurements as function of temperature. The I-V measurement revealed that conductivity of composite thin films increased as the temperature increased. The changes in resistance of the composite thin film sensor were utilized for detection of hydrogen gas. It was observed that at room temperature, MWNT doped PANI composite sensor shows higher response value and sensitivity with good repeatability in comparison to pure PANI thin film sensor. It was also observed that both PANI and MWNT doped PANI composite thin film based sensors showed unstable behavior as the temperature increased. The surface morphology of these composite thin films has also been characterized by scanning electron microscopy (SEM) measurement.

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