Issue 10, 2023

Role of graphene quantum dots with discrete band gaps on SnO2 nanodomes for NO2 gas sensors with an ultralow detection limit

Abstract

NO2 is a major air pollutant that should be monitored due to its harmful effects on the environment and human health. Semiconducting metal oxide-based gas sensors have been widely explored owing to their superior sensitivity towards NO2, but their high operating temperature (>200 °C) and low selectivity still limit their practical use in sensor devices. In this study, we decorated graphene quantum dots (GQDs) with discrete band gaps onto tin oxide nanodomes (GQD@SnO2 nanodomes), enabling room temperature (RT) sensing towards 5 ppm NO2 gas with a noticeable response ((Ra/Rg) − 1 = 4.8), which cannot be matched using pristine SnO2 nanodomes. In addition, the GQD@SnO2 nanodome based gas sensor shows an extremely low detection limit of 1.1 ppb and high selectivity compared to other pollutant gases (H2S, CO, C7H8, NH3, and CH3COCH3). The oxygen functional groups in GQDs specifically enhance NO2 accessibility by increasing the adsorption energy. Strong electron transfer from SnO2 to GQDs widens the electron depletion layer at SnO2, thereby improving the gas response over a broad temperature range (RT–150 °C). This result provides a basic perspective for utilizing zero-dimensional GQDs in high-performance gas sensors operating over a wide range of temperatures.

Graphical abstract: Role of graphene quantum dots with discrete band gaps on SnO2 nanodomes for NO2 gas sensors with an ultralow detection limit

Supplementary files

Article information

Article type
Paper
Submitted
19 ธ.ค. 2565
Accepted
10 เม.ย. 2566
First published
28 เม.ย. 2566
This article is Open Access
Creative Commons BY license

Nanoscale Adv., 2023,5, 2767-2775

Role of graphene quantum dots with discrete band gaps on SnO2 nanodomes for NO2 gas sensors with an ultralow detection limit

J. Lee, M. Park, Y. G. Song, D. Cho, K. Lee, Y. Shim and S. Jeon, Nanoscale Adv., 2023, 5, 2767 DOI: 10.1039/D2NA00925K

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