Context <p>The advancement of novel sensing materials significantly enhances the precision of early disease diagnosis and treatment. This study focuses on the fabrication of nano-sensing materials, specifically Janus arsenene/PtSeS (stacking-I and stacking-II), and examines their performance in strain sensing. The calculation results indicate that both stacking configurations exhibit excellent thermodynamic stability, with formation energies of − 3.27&#xa0;eV and − 3.35&#xa0;eV, respectively. Electronic structure analysis shows that both are indirect bandgap semiconductors, with bandgap values of 1.229&#xa0;eV and 0.845&#xa0;eV, respectively, and charge transfer occurs at the interface (net transfer amounts of 0.26 |e| and 0.28 |e|, respectively). Under applied tensile or compressive strain, ranging from 0 to 4%, the bandgaps of both heterojunctions exhibit a gradual decrease or increase. In the visible light spectrum, the absorption coefficient of the heterojunctions approaches approximately 1.6 × 10⁵&#xa0;cm⁻¹. These research outcomes are expected to facilitate the integration of these materials into medical diagnostic devices, including endoscopes.</p> Methods <p>All density functional theory calculations were conducted utilizing the CASTEP software package. The electron–electron exchange interaction was addressed through the Perdew-Burke-Ernzerhof functional, which operates within the framework of the generalized gradient approximation. To mitigate the known issue of band gap underestimation associated with the PBE functional, the Heyd-Scuseria-Ernzerhof hybrid functional was employed to enhance the electronic structure and optical absorption properties of the arsenene/PtSeS heterojunction.</p>