A Capacitive Humidity Sensor Based on Multi-Wall Carbon Nanotubes (MWCNTs)

Sensors

Wei-Ping Chen¹  Zhen-Gang Zhao¹  Xiao-Wei Liu¹  Zhong-Xin Zhang¹ 

[1] Department of Microelectronics, Harbin Institute of Technology, Harbin, Heilongjiang, China

关键词: capacitive sensor;    humidity sensor;    carbon nanotubes (CNTs);    capillary condensation;   

DOI  :  10.3390/s90907431

来源: mdpi

【 摘 要 】

A new type of capacitive humidity sensor is introduced in this paper. The sensor consists of two plate electrodes coated with MWCNT films and four pieces of isolating medium at the four corners of the sensor. According to capillary condensation, the capacitance signal of the sensor is sensitive to relative humidity (RH), which could be transformed to voltage signal by a capacitance to voltage converter circuit. The sensor is tested using different saturated saline solutions at the ambient temperature of 25 °C, which yielded approximately 11% to 97% RH, respectively. The function of the MWCNT films, the effect of electrode distance, the temperature character and the repeatability of the sensor are discussed in this paper.

【 授权许可】

CC BY   
© 2009 by the authors; licensee MDPI, Basel, Switzerland