In a study published recently in the journal Applied Surface Science, using first-principle predictions, the influence of transition metal (TM) dopants on improving PH3 detecting capability of h-BN nanosheets (BNNSs) was explored.
Study: Achieving optical phosphine sensitive h-BN nanosheets through transition metal doping. Image Credit: Shaiith/Shutterstock.com
Detecting phosphine (PH3) is a critical step in fumigation processes in stored grains, and the sensitivity of this identification largely relies on the effectiveness of sensory materials.
The Dangers Phosphine Fumigation Poses
Fumigation using phosphine (Hydrogen Phosphide, PH3) is a popular method for reducing pests in stored grains.
PH3 is a colorless, extremely poisonous, combustible gas having a fish or garlic-like stench.
It has an effect on the lungs and the central nervous system (CNS), causing pulmonary edemas. If even a moderate amount of PH3 is inhaled, it may cause significant harm or prove fatal for humans or animals.
As a result, rapid identification of unused PH3 with good sensitivity is critical for controlling the quality of food and protecting public health.
The Influence of Doping
In recent years, the discovery of nanoscale materials including monolayer BN, arsenene, graphene, MoS2, ZnS nanotubes, single-walled carbon nanotubes and others has heightened interest in phosphine gas sensing and associated theoretical research.
2D materials are particularly relevant among these nanoscale materials.
Owing to its unusual 2D structure, monolayer hexagonal boron nitride (h-BN) has received the most attention among other forms of BN. Nevertheless, pure monolayer h-BN has great chemical inertness and stability, which restricts its surface adsorption capability, changes such as flaws and doping are often produced to broaden its applicability.
Previous study has shown that platinum (Pt) dopants and vacancy defects may boost the PH3 adsorption capability of single-walled BN nanotubes (BNNTs).
It is discovered that the dopant atoms alter the electrical, optic, and surface features of BNNTs, such as electron density and molecular species adsorption.
There are also several studies that investigate the doping effects of graphene or other nanomaterials, demonstrating the efficiency of doping as a method to improve the surface adsorption capacity of 2D materials. However, research into BN nanosheets (BNNSs) doping for uses in hypersensitive optoelectronics is still in its early stages.
The phosphine detecting capabilities of transition metal (TM) enriched BNNSs were investigated using first-principle predictions in this work.
The effect of TM dopants on morphological, electrical, and optical characteristics was first investigated, followed by a comparison of the PH3 adsorptive capability of several TM-doped BNNSs, as well as their reactions to phosphine adsorption in optic and electrical features.
The findings reveal that TM doping may improve the PH3 adsorptive capability of BNNS and that the electrical and optical characteristics of TM-doped BNNSs are highly responsive to PH3 adsorption, implying that TM doping can effectively bring optical phosphine sensitivity to the BNNS.
Important Findings of the Study
In summary, first-principles simulations were used to study the effects of TM doping on the structural, electrical, and optical characteristics of BNNS, as well as its ability to detect PH3 molecules.
As dopants, a number of TM elements (Ti, Cr, Fe, Mo, and W) were investigated.
The TM-doped BNNSs were found to be fundamentally stable, with negative cohesion energies and hybrid ionic and covalent TM-N connections, and the TM doping altered the electrical characteristics of the BNNS, considerably increasing its ability to adsorb PH3.
It was discovered that PH3 adsorption narrows the band gaps of TM-doped BNNSs and influences their optical characteristics.
Among the several TM-doped BNNSs tested, the W-doped BNNS exhibited the highest PH3 adsorptive capability and the biggest reactions in electrical and optical characteristics to PH3 adsorption.
Following PH3 adsorption, the W doped BNNS had the narrowest bandgap and the greatest raise in static refractive index and static dielectric constant in the perpendicular polarization, as well as the greatest change in refractive index and absorption coefficient for UVC light in the parallel polarization.
This study demonstrated the methodology and effectiveness of phosphine detection utilizing TM-doped BNNSs as an optical responsive material, which is prospective for use in phosphine sensing in fumigation processes in stored grains and may be useful for the design of related materials and systems.
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Xu, K., Tang, Y., Wu, C., Zhao, Z., Sun, L., & Li, Y. (2022). Achieving optical phosphine sensitive h-BN nanosheets through transition. Applied Surface Science. Available at: https://www.sciencedirect.com/science/article/pii/S0169433222002811?via%3Dihub