Crb>2b>Ob>3b>-activated ZnO thick film resistors for ammonia gas sensing operable at room temperature

详细信息	查看全文 | 推荐本文 |

• 作者：D.R. Patil ; L.A. Patil ; P.P. Patil
• 关键词：Crb>2b>Ob>3b>-activated ZnO ; Thick films ; Room temperature ; NHb>3b> gas sensor
• 刊名：Sensors and Actuators B ; Chemical
• 出版年：2007
• 期刊代码：161_09254005
• 类别：et
• 出版时间：1 October 2007
• 卷：126
• 期：2
• 页码：368-374
• 文件大小：1070 K

摘要

Pure ZnO thick films, prepared by screen-printing technique, were almost insensitive to NHb>3b>. Pure ZnO thick films were surface activated with Cr³⁺ by dipping them into an aqueous solution (0.01 M) of chromium trioxide CrOb>3b> for different intervals of time and fired at 500 °C for 24 h. The CrOb>3b> is known to be unstable above 197 °C and transforms into Crb>2b>Ob>3b> upon firing above 197 °C. The grains of Crb>2b>Ob>3b> would disperse around the grains of ZnO base material. The Cr³⁺-activated ZnO films dipped for 5 min were observed to be sensitive and highly selective to 300 ppm of NHb>3b> gas at room temperature. The effects of surface microstructure and Cr³⁺ concentrations on the sensitivity, selectivity, response and recovery of the sensor in the presence of NHb>3b> and other gases were studied and discussed. The better performance could be attributed to an optimum number of surface misfits in terms of Crb>2b>Ob>3b> on the ZnO films.