Collaborative Enhancement of Humidity Sensing Performance by KCl-Doped CuO/SnO2 p-n Heterostructures for Monitoring Human Activities

Lei Wang; Feng Huang; Xinqi Yao; Shuaishuai Yuan; Xinhai Yu; Shan-Tung Tu; Shijian Chen

doi:10.1021/acsomega.2c07098

Collaborative Enhancement of Humidity Sensing Performance by KCl-Doped CuO/SnO₂ p-n Heterostructures for Monitoring Human Activities

ACS Omega. 2023 Jan 26;8(5):4878-4888. doi: 10.1021/acsomega.2c07098. eCollection 2023 Feb 7.

Authors

Lei Wang^{1

2}, Feng Huang^{1

2}, Xinqi Yao^{1

2}, Shuaishuai Yuan^{1

2}, Xinhai Yu^{1

2}, Shan-Tung Tu^{1

2}, Shijian Chen³

Affiliations

¹ MOE Key Laboratory of Pressure Systems and Safety, East China University of Science and Technology, Shanghai 200237, P. R. China.
² School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China.
³ SUFA Technology Industry Co., Ltd., CNNC, Suzhou 215001, P. R. China.

Abstract

In this study, a high-performance humidity sensor based on KCl-doped CuO/SnO₂ p-n heterostructures was fabricated by a ball milling-roasting method. The morphology and nanostructure of the fabricated KCl-CuO/SnO₂ composite were characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and nitrogen sorption analysis. The results showed that the humidity sensor had a high sensitivity of 194 kΩ/%RH, short response and recovery times of 1.0 and 1.5 s, a low hysteresis value, and good repeatability. The energy band structure and complex impedance spectrum of the KCl-CuO/SnO₂ composite indicated that the excellent humidity sensing performance originated from the ionic conductivity of KCl, the formation of heterojunctions, the change in the Schottky barrier height, and the depletion of electronic depletion layers. The KCl-CuO/SnO₂ sensor has great potential in respiratory monitoring, noncontact sensing of finger moisture, and environmental monitoring.