Layered SnSe₂ flakes and SnSe₂/SnO₂ heterojunction-based chemiresistive-type sensors demonstrate good gas sensing properties at low temperatures. The pure SnSe₂-based chemiresistive-type sensor exhibited good response and recovery to both NO₂ and NH₃ while also showing a moderate response to hydrogen, CO, C₃H₆ and several typical volatile organic vapors, such as methanol, ethanol, acetone and formaldehyde, near room temperature, indicating that it possesses poor selectivity. However, compared to pristine SnSe₂, a SnSe₂/SnO₂ heterojunction-based chemiresistive-type sensor prepared by the thermal oxidation method showed greatly improved sensitivity and superior selectivity toward NO₂ at 120 °C. Such impressive improvements in the sensing performance can be attributed to the formation of SnSe₂/SnO₂ heterojunctions. The density functional theory (DFT) calculations revealed that there was a lower adsorption energy and greater Bader charge value between the adsorbed NO₂ and SnSe₂/SnO₂ heterojunction materials.

中文翻译：

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层状SnSe2微米薄片和SnSe2 / SnO2异质结，用于低温化学阻隔型气体传感

层状SnSe ₂薄片和SnSe ₂ / SnO ₂基于异质结的化学阻隔型传感器在低温下显示出良好的气体传感性能。纯SnSe ₂基化学阻隔型传感器对NO ₂和NH ₃均表现出良好的响应和回收率，同时对氢，CO，C ₃ H ₆和几种典型的挥发性有机蒸气（例如甲醇，乙醇，接近室温的丙酮和甲醛，表明它的选择性差。但是，与原始的SnSe ₂相比，SnSe ₂ / SnO ₂通过热氧化法制备的基于异质结的化学阻隔型传感器在120°C时显示出大大提高的灵敏度和对NO _2的优异选择性。感测性能的如此显着改善可归因于SnSe ₂ / SnO ₂异质结的形成。密度泛函理论（DFT）计算表明，被吸附的NO ₂和SnSe ₂ / SnO ₂异质结材料之间的吸附能较低，巴德电荷值较大。