Humidity Sensing Behavior of Endohedral Li-Doped and Undoped SWCNT/SDBS Composite Films

Sensors

Christian Müller¹  JoséMauricio Rosolen²  ElaineYoshiko Matsubara²  Ammar Al-Hamry³  Olfa Kanoun³  Mahfujur Rahaman⁴  DietrichR. T. Zahn⁴ 

[1] Departamento de Física, Universidade Federal de Santa Catarina, Florianopolis 88040-900, Brazil;Faculdade de Filosofia Ciencias e Letras de Ribeirão Preto-Departamento de Química-Universidade de São Paulo, Ribeirão Preto 14040-901, Brazil;Measurement and Sensor Technology, Chemnitz University of Technology, D-09107 Chemnitz, Germany;Semiconductor Physics, Chemnitz University of Technology, D-09107 Chemnitz, Germany;

关键词: carbon nanotubes;    thin films;    humidity sensor;    temperature sensor;    impedance spectroscopy;    Raman spectroscopy;    electron microscopy;   

DOI  :  10.3390/s19010171

来源: DOAJ

【 摘 要 】

We have investigated single-walled carbon nanotube (SWCNT) networks wrapped with the cationic surfactant sodium dodecyl-benzenesulfonate (SBDS) as promising candidates for water detection. This is the first time that the humidity behavior of endohedral Li-doped (Li@) and undoped SWCNTs/SDBS has been shown. We identified a strong and almost monotonic decrease in resistance as humidity increased from 11 to 97%. Sensitivities varied between −3 and 65% in the entire humidity range. Electrical characterization, Raman spectroscopy, and high-resolution transmission electron microscopy (HRTEM) analysis revealed that a combination of the electron donor behavior of the water molecules with Poole-Frenkel conduction accounted for the resistive humidity response in the Li@SWCNT/SDBS and undoped SWCNT/SDBS networks. We found that Li@SWCNTs boosted the semiconducting character in mixtures of metallic/semiconducting SWCNT beams. Moreover, electrical characterization of the sensor suggested that endohedral Li doping produced SWCNT beams with high concentration of semiconducting tubes. We also investigated how frequency influenced film humidity sensing behavior and how this behavior of SWCNT/SDBS films depended on temperature from 20 to 80°C. The present results will certainly aid design and optimization of SWCNT films with different dopants for humidity or gas sensing in general.

【 授权许可】

Unknown