Zhang Chunmei, Jiao Yalong, Ma Fengxian, Kasi Matta Sri, Bottle Steven, Du Aijun
School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Gardens Point Campus, QLD 4001, Brisbane, Australia.
Beilstein J Nanotechnol. 2018 Jun 5;9:1641-1646. doi: 10.3762/bjnano.9.156. eCollection 2018.
The detection of single gas molecules is a highly challenging work because it requires sensors with an ultra-high level of sensitivity. By using density functional theory, here we demonstrate that the adsorption of a paramagnetic unpaired free radical gas (NO) on a monolayer of XS (X = Mo, W) can trigger the transition from semiconductor to half metal. More precisely, the single-layer XS (X = Mo, W) with NO adsorbed on it would behave like a metal in one spin channel while acting as a semiconductor in the other spin orientation. The half-metallicity is robust and independent of the NO concentration. In contrast, no half-metallic feature can be observed after the adsorption of other free radical gases such as NO. The unique change in electronic properties after the adsorption of NO on transition-metal sulfides highlights an effective strategy to distinguish NO from other gas species by experimentally measuring spin-resolved transmission. Our results also suggest XS (X = Mo, W) nanosheets can act as promising nanoscale NO sensors.
单个气体分子的检测是一项极具挑战性的工作，因为它需要具有超高灵敏度的传感器。通过使用密度泛函理论，我们在此证明，顺磁性未配对自由基气体（NO）在单层XS（X = Mo、W）上的吸附可引发从半导体到半金属的转变。更确切地说，吸附有NO的单层XS（X = Mo、W）在一个自旋通道中表现得像金属，而在另一个自旋取向上则充当半导体。这种半金属性很强，且与NO浓度无关。相比之下，吸附其他自由基气体（如NO₂）后未观察到半金属特性。NO吸附在过渡金属硫化物上后电子性质的独特变化突出了一种通过实验测量自旋分辨传输来区分NO与其他气体种类的有效策略。我们的结果还表明，XS（X = Mo、W）纳米片可作为有前景的纳米级NO传感器。
