Visible Light-Induced Room-Temperature Formaldehyde Gas Sensor Based on Porous Three-Dimensional ZnO Nanorod Clusters with Rich Oxygen Vacancies

Bo Zhang; Jing Wang; Qufu Wei; Pingping Yu; Shuai Zhang; Yin Xu; Yue Dong; Yi Ni; Jinping Ao; Yi Xia

doi:10.1021/acsomega.2c02613

Visible Light-Induced Room-Temperature Formaldehyde Gas Sensor Based on Porous Three-Dimensional ZnO Nanorod Clusters with Rich Oxygen Vacancies

ACS Omega. 2022 Jun 21;7(26):22861-22871. doi: 10.1021/acsomega.2c02613. eCollection 2022 Jul 5.

Authors

Bo Zhang¹, Jing Wang², Qufu Wei³, Pingping Yu¹, Shuai Zhang¹, Yin Xu¹, Yue Dong¹, Yi Ni¹, Jinping Ao¹, Yi Xia⁴

Affiliations

¹ Engineering Research Center of IoT Technology Applications (Ministry of Education), Department of Electronic Engineering, Institute of Advanced Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China.
² Key Laboratory of Synthetic and Biological Colloids (Ministry of Education), School of Chemical and Material Engineering, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China.
³ Key Laboratory of Eco-Textiles (Ministry of Education), Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China.
⁴ Research Center for Analysis and Measurement, Kunming University of Science and Technology, and Analytic & Testing Research Center of Yunnan, Kunming 650093, China.

Abstract

Oxygen vacancy (V_O) is a kind of primary point defect that extensively exists in semiconductor metal oxides (SMOs). Owing to some of its inherent qualities, an artificial manipulation of V_O content in one material has evolved into a hot research field, which is deemed to be capable of modulating band structures and surface characteristics of SMOs. Specific to the gas-sensing area, V_O engineering of sensing materials has become an effective means in enhancing sensor response and inducing light-enhanced sensing. In this work, a high-efficiency microwave hydrothermal treatment was utilized to prepare a V_O-rich ZnO sample without additional reagents. The X-ray photoelectron spectroscopy test revealed a significant increase in V_O proportion, which was from 9.21% in commercial ZnO to 36.27% in synthesized V_O-rich ZnO possessing three-dimensional and air-permeable microstructures. The subsequent UV-vis-NIR absorption and photoluminescence spectroscopy indicated an extension absorption in the visible region and band gap reduction of V_O-rich ZnO. It turned out that the V_O-rich ZnO-based sensor exhibited a considerable response of 63% toward 1 ppm HCHO at room temperature (RT, 25 °C) under visible light irradiation. Particularly, the response/recovery time was only 32/20 s for 1 ppm HCHO and further shortened to 10/5 s for 10 ppm HCHO, which was an excellent performance and comparable to most sensors working at high temperatures. The results in this work strongly suggested the availability of V_O engineering and also provided a meaningful candidate for researchers to develop high-performance RT sensors detecting volatile organic compounds.