Characteristics of humidity and gas sensors with TiO2 nanotubes

• Main Authors: Pei-Cen Wu, 吳佩岑
• Other Authors: Te-Hua Fang
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/2cdqxu

碩士 === 國立高雄應用科技大學 === 機械與精密工程研究所 === 103 === Surface and structural properties of un-annealed TiO2 nanotubes and those annealed at different temperatures were investigated by electrochemical methods. Improvement of CO gas and humidity sensing property was obtained based on a heterojunction between semiconducting materials, as p-type perovskite structures and n-type TiO2 nanotubes. The contact angle became smaller and the surface exhibited hydrophilic behavior at TiO2 nanotubes with larger diameters. After anodized treatment of TiO2 nanotubes, causing the surface of different color. With the UV/Vis spectrum to verify the optical color. Increasing the relative humidity, the sensor will become more conductive, because of the increase the number of free electrons. The sensitivity of gas sensor was the best when the TiO2 nanotubes sample after N2/H2 annealing atmosphere. For p-n junction, the p-type La0.8Sr0.5Co0.5Ni0.5O3-x (LSCNO) almost became pervoskite structure at 600℃. While the n-type TiO2 nanotubes after annealing at 500℃ have a good sense characteristics for CO gas sensor. TiO2/LSCNO heterocontact device has a sensitivity of 38.41% for detection 400 ppm CO at 200℃. The result was good for resilience and reproducibility showed the optimum dynamic. The heterojunction of sensitivity enhanced the value of CO gas sensing and low temperature operation.