Au-modified three-dimensionally ordered macroporous ZnO:In for high-performance ethanol sensors

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 8; no. 8; pp. 2812 - 2819
• Main Authors: Wang, Zhihua, Tian, Ziwei, Han, Dongmei, Gu, Fubo
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 28.02.2020
• Subjects: Carrier density; Depletion; Ethanol; Operating temperature; Selectivity; Sensitivity; Sensors; Zinc oxide
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c9tc06750g

In this paper, Au-modified three-dimensionally ordered macroporous ZnO:In (3DOM Au-ZnO:In) was synthesized by a one-pot method using a PMMA colloidal crystal template. The 3DOM ZnO:In with uniformly dispersed Au had large specific surface areas and highly ordered pore structures. The ethanol-sensing properties of 3DOM Au-ZnO:In were investigated and the sensor based on the 0.050 mol% Au-loaded 3DOM ZnO:In exhibited the highest sensitivity (∼240) to 100 ppm ethanol at the optimum operating temperature of 250 °C. Moreover, the fabricated sensor exhibited excellent selectivity and good stability. Therefore, the Au-modified 3DOM ZnO:In is a promising material for a novel ethanol sensor. The reason for the improvement of the sensitivity was investigated. The large surface area of the 3DOM structure was beneficial for gas adsorption and transfer, and In-doping can increase the electron carrier concentration. Moreover, Au modification enhanced the content of adsorbed oxygen, and thus resulted in a thick depletion layer and high sensitivity. Au-modified three-dimensionally ordered macroporous ZnO:In with very low Au content exhibited high sensitivity to ethanol.