School of Physical Science and Technology, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, China.
ACS Sens. 2024 Oct 25;9(10):5179-5187. doi: 10.1021/acssensors.4c01212. Epub 2024 Sep 30.
Transition metal oxide semiconductors have great potential for use in H sensors, but in recent years, the strange phenomena about gas-sensitive performance associated with their special properties have been more widely discussed in research. In some cases, the resistance of transition metal oxide gas sensors will emerge with some changes contrary to their intrinsic semiconductor characteristics, especially in gas sensor research of WO. Based on the hydrothermal synthesis of WO, our work focuses on the abnormal change of tungsten oxide resistance to different gases at low temperature (80-200 °C) and high temperature (above 200 °C). Through in situ FT-IR and in situ XPS, combined with density functional theory calculations, a new reasonable explanation of WO is proposed for the abnormal resistance change caused by temperature and the strange response due to gas concentration. The occurrence of these findings can be attributed to the synergistic effect resulting from the presence of two contributing factors. One of them is attributed to the alteration in the surface valence state of WO induced by gas, resulting in the reduction of W. The other one is due to the reaction between gas and adsorbed oxygen on the surface of WO. This work presents a novel and rational concept for addressing the reaction mechanism between gas and transition metal oxide semiconductors, thereby paving the way for the development of highly efficient gas sensors based on transition metal oxide semiconductors.
过渡金属氧化物半导体在 H 传感器中有很大的应用潜力，但近年来，关于其特殊性质与气体敏感性能相关的奇异现象在研究中得到了更广泛的讨论。在某些情况下，过渡金属氧化物气体传感器的电阻会出现与本征半导体特性相反的一些变化，特别是在 WO 的气体传感器研究中。基于 WO 的水热合成，我们的工作主要集中在低温（80-200°C）和高温（200°C 以上）下不同气体对氧化钨电阻的异常变化上。通过原位 FT-IR 和原位 XPS 以及密度泛函理论计算，对温度引起的 WO 异常电阻变化和气体浓度引起的奇怪响应提出了一个新的合理解释。这些发现的发生可以归因于两个贡献因素的协同效应。其中之一是气体引起的 WO 表面价态的改变，导致 W 的减少。另一个是由于气体与 WO 表面吸附氧之间的反应。这项工作提出了一个新的合理概念，用于解决气体与过渡金属氧化物半导体之间的反应机制，从而为基于过渡金属氧化物半导体的高效气体传感器的发展铺平了道路。
