Revealing a Highly Sensitive Sub-ppb-Level NO₂ Gas-Sensing Capability of Novel Architecture 2D/0D MoS₂/SnS Heterostructures with DFT Interpretation

Abstract

In this work, we use a chemical method to design novel 2D-material/0D-quantum dot (MoS2/SnS) heterostructures. Furthermore, the unique 2D/0D heterostructure enhanced the NO2 gas-sensing capability 3 times and increased the sensing recoverability by more than 90%. Advanced characterization tools such as SEM, TEM, XRD, and AFM confirm the formation of MoS2/SnS heterojunction nanomaterials. Using AFM data, the average thickness of the MoS2 layer was found to be 5 nm. The highest sensor response of 0.33 with good repeatability was observed at 250 ppb of NO2. Sensing characterization reveals the ultra-fast response time, that is, 74 s, at 50 ppb of NO2. The limit of detection for detecting NO2 was also found to be very low, that is, 0.54 ppb, by using MoS2/SnS heterostructures. The theoretical calculations based on density functional theory well corroborated and quantified the intermolecular interaction and gas adsorption on the surface of MoS2/SnS.

Photocurrent conversion capability of a 2D WS2-polyvinyl alcohol matrix and its DFT-based charge carrier dynamics analysis

“…66 In the metallopolymeric system, there is contact between them because the W atom is in the WS 2 and the –OH functional group is in the PVOH matrix. There are certain electronic parameters, such as HOMO–LUMO gap (Δ E ), electron affinity (EA), ionization potential (IP), electronegativity ( μ ), chemical potential ( χ ), chemical hardness ( η ), chemical softness ( σ ), and nucleophilicity index ( ω ), which can be calculated by relations (17)–(24), 67–69 to investigate the properties of the metallopolymeric system as presented in Table 3.…”

A Rapid ppb Level Room Temperature NO2 Sensing by Using BiVO4–CeO2 Composites with DFT Interpretation

“…The SDD basis set, which combines DZ and the Stuttgary-Dresden ECP basis set for improved reliability and precision, might lessen the burden of the large number of electrons in f-block elements. Various parameters such as the HOMO–LUMO gap, ionization potential electron affinity, and electronegativity have been calculated by using the energy of higher occupied molecular orbitals (HOMOs) and lower unoccupied molecular orbitals (LUMOs) according to the information presented in our prior articles. − …”

Recent advancements in nano sensors for air and water pollution control

“…The results showed that doping with B, N, or Al can greatly improve GQD's adsorbing capabilities and they serve as a promising application towards NO 2 gas sensing. Kumar et al, 94 designed a novel 2D-material/0Dquantum dot (MoS 2 /SnS) heterostructure with highly sensitive subppb-level NO 2 gas-sensing capability. The structure showed 3 times enhanced NO 2 gas-sensing capability and recovery increase by more than 90%.…”