Optical ammonia gas sensor based on a porous silicon rugate filter coated with polymer-supported dye

Gas Sensors for Monitoring Air Pollution

“…For example, the WO 3 nanofibers showed rapid response and recovery characteristics to NH 3 , and gas-sensing mechanism was explained in terms of surface resistivity and barrier height model [70,71]. It was reported that polypyrrole (PPy)/ZnSnO 3 nanocomposites also exhibited a higher response to NH 3 gas [72], and by combining the merits of a chitosan polymer and a porous Si photonic crystal, the optical sensor showed high sensitivity, selectivity, and stability [69].…”

“…It presents many hazards to both humans and environment. Detection of NH 3 is required in many applications, including leak-detection in air-conditioning systems as well as in sensing of trace amounts of ambient NH 3 in air for environmental analysis, breath analysis for medical diagnoses, animal housing, and more [69]. Recently, various NH 3 gas sensors based on different sensing mechanisms have been developed.…”

A new sensor for ammonia based on cyanidin-sensitized titanium dioxide film operating at room temperature

“…In the past decade, many kinds of ammonia sensors have been developed based on different sensing mechanisms [1,2,[5][6][7][8][9]. These include electrical [10], mass [11], or optical-based methods [12]. Though they comment on different measurement principles, nearly all commercial ammonia sensors are based on either electrochemical or chemoresistive metal oxide (doped SnO 2 ) principles.…”

Sensitive Films for Optical Detection of Ammonia and Nitrogen Dioxide

“…Among the materials that change their absorption spectrum upon interaction with gases are pH-indicators. In the paper [7] there was shown the reective ammonia sensor utilizing pH-dyes immobilized in porous silica lms produced by means of thermal oxidation of etched silicon wafers and in chitosan/GPTMS lms (GPTMS glycidoxypropyltrimethoxysilane). In our research group dyes are immobilized in porous silica lms fabricated by means of sol--gel method [8,9].…”