Highly Sensitive Photo-activated Sensors Based on Iron, Nitrogen Co-modified Peroxo Titanic Thin Film for Gas and Humidity Sensing
Date Issued
2014
Date
2014
Author(s)
CHANG, JUI-LIN
Abstract
Gas sensors can be utilized to detect volatile organic compounds (VOCs) or humidity. Volatile organic compound sensors and humidity sensors can be applied in many fields. In this research, we synthesized a new material consisting of iron and nitrogen co-modified peroxo titanium oxide, for the VOCs and humidity sensing applications. We developed a sol-gel technology to synthesize iron, nitrogen co-modified peroxo titanium oxide and the ratio of iron, nitrogen and titanium can be adjuted. UV light was used to improve the sensing performance of humidity and VOCs.
This sensor has great response to humidity and the impedance value varies a lot with different frequencies. When using a impedance analyzer to measure the impedance change, the impedance change spanned almost five orders of magnitude during the measurement of relative humidity (RH) from 11%-75% under 100Hz.
On the other hand, the sensor can measure the methanol and toluene from 6000 to 10000 ppm. We proved that our sensors have good improvements after illuminating 365nm ultraviolet light for 15 minutes. Our sensors have good selectivity between methanol and ethanol .
Our sensors’ response time and recovery time are less than 2s to water, and approximately 20s to VOCs. Because the material surface is hydrophilic so water molecules can easily be adsorbed. It is believed that VOCs have to compete to the water molecules for reaction sites and thus the response time is slower than water.
Subjects
氣體感測器
濕度感測器
鐵氮共摻雜氧化鈦
光激發
溶膠凝膠法
Type
thesis
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