Effect of SnO2 particle size on gas-sensing performance for ppb-level NO2 at room temperature under UV light

The particle sizes of sensitive material have significant influence on the gas property. We reported at room temperature NO2 gas sensor using SnO2 particles of various size to investigate their impact on sensing performance in a wide concentration range, even at ppb level. Results showed that the gas response increases with the decrease of particle size, mainly attributed to the larger specific surface area of small size to absorb more target gas. The SnO2-40 nm exhibited the highest response to low concentrations of NO2 gas, reaching a value of 106 at 5 ppm, and it can detect trace amounts of NO2 with a detection limit of 100 ppb. The mechanism of gas sensing property is discussed, highlighting the relationship between small size and large specific surface area. This paper provides useful guideline for fabrication high-performance gas sensor with optimized particle sizes.