First principle analysis of toxic gas adsorption on pristine WS2 and Fe-doped WS2: Implications for gas sensing

Transition metal dichalcogenides (TMDs), such as MoS2 and WS2, are the focus of current research. TMDs are employed in many applications, including optoelectronic, solar cells, gas sensing, rechargeable batteries, and spintronic devices. In the existing work, we have explored the stability of pristine and Iron (Fe) doped WS2 and the adsorption property towards harmful gases such as NO, NO2, NH3, BCl3, and SO2 by executing the first principles calculations. To analyse the electronic properties of pristine and Iron (Fe) doped WS2, band structure, the density of states, the projected density of states, electrostatic difference density, electrostatic localisation function, binding energy and charge transfer of the systems have been calculated. To study the adsorption property of the systems, adsorption energy, adsorption distance, recovery time and work function have been evaluated. Our findings represented that Fe-doped WS2 has higher magnitude charge transfer and good conductivity than pristine WS2. Also, the adsorption analysis towards the gas molecules shows that the Fe-doped WS2 shows prominent adsorption for NO, BCl3 and SO2 compared with pristine WS2. And the physisorption nature of gas molecules is noticed through no electron localisation overlap for Fe-doped WS2 and pristine WS2 systems. Therefore, we concluded that Fe-doped WS2 is ideal for gas-sensing applications.