Detection of volatile
organic compounds (VOCs) at room temperature
(RT) currently remains a challenge for metal oxide semiconductor (MOS)
gas sensors. Herein, for the first time, we report on the utilization
of porous SnO2 thin films for RT detection of VOCs by defect
engineering of oxygen vacancies. The oxygen vacancies in the three-dimensional-ordered
SnO2 thin films, prepared by a colloidal template method,
can be readily manipulated by thermal annealing at different temperatures.
It is found that oxygen vacancies play an important role in the RT
sensing performances, which successfully enables the sensor to respond
to triethylamine (TEA) with an ultrahigh response, for example, 150.5–10
ppm TEA in a highly selective manner. In addition, the sensor based
on oxygen vacancy-rich SnO2 thin films delivers a fast
response and recovery speed (53 and 120 s), which can be further shortened
to 10 and 36 s by elevating the working temperature to 120 °C.
Notably, a low detection limit of 110 ppb has been obtained at RT.
The overall performances surpass most previous reports on TEA detection
at RT. The outstanding sensing properties can be attributed to the
porous structure with abundant oxygen vacancies, which can improve
the adsorption of molecules. The oxygen vacancy engineering strategy
and the on-chip fabrication of porous MOS thin film sensing layers
deliver great potential for creating high-performance RT sensors.
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