High response of Cl₂ gas via Janus In₂SSe/Al₂SSe in-plane heterostructures

The development of efficient sensing platforms for highly toxic gases remains a critical challenge in environmental monitoring and industrial safety. Despite the remarkable progress of two-dimensional heterostructures, their temperature-dependent gas-sensing behavior remains poorly understood, limiting their practical applicability. To address this gap, the gas-sensing performance of in-plane In₂SSe/Al₂SSe (X/Y), In₂SSe/Al₂SSe/In₂SSe (X/Y/X), and Al₂SSe/In₂SSe/Al₂SSe (Y/X/Y) heterostructures was systematically investigated over a wide temperature range. Interface engineering effectively modulates the electronic structure and adsorption behavior, resulting in enhanced sensing performance. The Y/X/Y heterostructure exhibits the highest response toward Cl₂ (17,521.68 at 298 K), whereas ClCN shows the strongest adsorption (- 2.46 eV). These findings demonstrate the potential of interface-engineered Janus heterostructures as thermally robust platforms for next-generation toxic-gas sensing.

Density functional theory (DFT) calculations were performed using the DMol³ module in Materials Studio. The Generalized Gradient Approximation (GGA) with the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional and the Tkatchenko-Scheffler (TS) van der Waals correction was employed. A Double Numerical plus Polarization (DNP) basis set was used to describe the atomic orbitals, while the Density Functional Semi-Core Pseudopotential (DSPP) was applied for core-electron treatment. All calculations were performed under spin-unrestricted conditions.