Synergistic Effect of Electron Scattering and Space Charge Transfer Enabled Unprecedented Room Temperature NO2 Sensing Response of SnO2

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 19; no. 48; pp. e2303631 - n/a
• Main Authors: Zhang, Yajie, Jiang, Yadong, Yuan, Zhen, Liu, Bohao, Zhao, Qiuni, Huang, Qi, Li, Ziteng, Zeng, Wen, Duan, Zaihua, Tai, Huiling
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 28.11.2023
• Subjects: Acetylacetone; Basic oxides; Charge transfer; electron scattering; Gas sensors; high response; Metal oxides; Nanoparticles; Nitrogen dioxide; NO2 sensors; Power consumption; Room temperature; Scattering; Sensors; SnO2; Space charge; space charge transfer; Synergistic effect; Tin dioxide
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202303631

Metal oxide gas sensors have long faced the challenge of low response and poor selectivity, especially at room temperature (RT). Herein, a synergistic effect of electron scattering and space charge transfer is proposed to comprehensively improve gas sensing performance of n‐type metal oxides toward oxidizing NO2 (electron acceptor) at RT. To this end, the porous SnO2 nanoparticles (NPs) assembled from grains of about 4 nm with rich oxygen vacancies are developed through an acetylacetone‐assisted solvent evaporation approach combined with precise N2 and air calcinations. The results show that the as‐fabricated porous SnO2 NPs sensor exhibits an unprecedented NO2‐sensing performance, including outstanding response (Rg/Ra = 772.33 @ 5 ppm), fast recovery (<2 s), an extremely low detection limit (10 ppb), and exceptional selectivity (response ratio >30) at RT. Theoretical calculation and experimental tests confirm that the excellent NO2 sensing performance is mainly attributed to the unique synergistic effect of electron scattering and space charge transfer. This work proposes a useful strategy for developing high‐performance RT NO2 sensors using metal oxides, and provides an in‐depth understanding for the basic characteristics of the synergistic effect on gas sensing, paving the way for efficient and low power consumption gas detection at RT. To develop the room temperature NO2 sensor with high response, fast recovery, and exceptional selectivity, porous SnO2 nanoparticles with rich oxygen vacancies are synthesized via acetylacetone‐assisted solvent evaporation followed by N2 and air calcinations. The fascinating sensing properties are mainly attributed to the unique synergistic effect of electron scattering and space charge transfer.