First-Principles Investigation of Adsorption Behaviors and Electronic, Optical, and Gas-Sensing Properties of Pure and Pd-Decorated GeS₂ Monolayers

Abstract

The extensive applications of two-dimensional (2D) transition metal disulfides in gas sensing prompt us to explore the adsorption, electronic, optical, and gas-sensing properties of the pure and Pd-decorated GeS2 monolayers interacting with NO2, NO, CO2, CO, SO2, NH3, H2S, HCN, HF, CH4, N2, and H2 gases by using first-principles methods. Our results showed that the pure GeS2 monolayer is not appropriate to develop gas sensors. The stability of the Pd-decorated GeS2 (Pd-GeS2) monolayer was determined by binding energy, transition state theory, and molecular dynamics simulations, and the Pd decoration has a significant effect on adsorption strength and the change in electronic properties (especially electrical conductivity). The Pd-GeS2 monolayer-based sensor has relatively high sensitivity toward NO and NO2 gases with moderate recovery time. In addition, the adsorption of NO and NO2 can conspicuously change the optical properties of the Pd-GeS2 monolayer. Therefore, the Pd-GeS2 monolayer is predicted to be reusable and a highly sensitive (optical) gas sensing material for the detection of NO and NO2.

Transition Metal (Cu, Pd, and Ag)-Modified Nb2S2C Monolayer for Highly Efficient Catechol Sensing: A First-Principles Investigation

“…The relatively low value of adsorption energy and high adsorption distance between the Cc and the monolayer indicates the predominance of strong physisorption . In the pursuit of developing an efficient sensor, it is often desirable that the interaction should be strong enough to retain the Cc on the substrate surface, i.e., a weak chemisorption is often preferred . Therefore, the surface of the Nb 2 S 2 C monolayer is modified with TM functionalization to attain weak chemisorption of the Cc molecule.…”

Gas Sensing Properties of Pd-Decorated GeSe Monolayer toward Formaldehyde and Benzene Molecules: A First-Principles Study

“…Earlier studies − have reported that the type of molecule can also be distinguished by the differences in the optical properties of the adsorption of various molecules on the same substrate. Here, we will discuss the visible light absorption of doped cases in Figure .…”

“…This behavior is due to its excellent electronaccepting/donating behavior when interacting with the substrate and gas. Previous studies 34,59 have reported that the DOS variation of a system before and after adsorption can indicate the type of adsorption. Thus, to further confirm this point, the total density of states (TDOS) and projected density of states (PDOS) are discussed in Figure 5.…”

Electrical contact properties of 2D metal-semiconductor heterojunctions composed of different phases of NbS₂ and GeS₂

“…迄今为止， 3 GeS 2 纳米片的各种物理性质已经得到了广泛的研究. Gao 等人研究了 Pd 修饰 GeS 2 单层的吸附 行为及电子、光学和气敏特性 [25]. Ruan 等人研究发现拉伸应变可提高单层 GeS 2 的热电性能 [26] .…”