AB Initio Study on Functionalised WS2 Monolayer for Gas Sensing Application

Abstract

In this research work the functionalisation of WS2 is done, through newlinethe substitutional doping method using the transition metal (TM) atoms Fe, Co, and Ni, newlinewith various concentrations to enhance the carrier concentration of the system which newlineimproves the electronic characteristics of pristine WS2. Initially, we studied the stability newlineof the pristine WS2 and functionalized WS2 using the perturbation method, phonon band newlinestructure, and formation energy where the stability is achieved by having minimal total newlineenergy, positive frequency phonon modes and maximum formation energy. So, we newlineconcluded that the higher concentration system exhibits greater stability. Further, we newlineproceeded with the analysis of adsorption behavior and the gas-sensing properties of newlinehigher concentration functionalized WS2 (i.e., Fe3W16S29, Co3W16S29 and Ni3W16S29) for newlineNO, NO2, NH3, BCl3 and SO2 gas molecules based on density functional theory. All the newlinegas molecules show better adsorption towards functionalized WS2 monolayer through newlinevan der Waals and covalent interaction. To describe the strength of adsorption between newlinethe gas molecule and the functionalized WS2, the adsorption energy, charge transfer, newlineadsorption distance, electron localization function, and electron difference density were newlinecalculated. Based on the results, we confirmed that Fe3W16S29 shows better adsorption newlinetowards BCl3 and SO2 with high adsorption energy (-1.68 eV and -0.93 eV), great charge newlinetransfer (-0.468 e and -0.258 e) and reasonable recovery time at 473 K and 673 K