Flexible Mo₂TiC₂T_x/TaS₂ van der Waals heterostructure films for bias‑free dual‑mode sensing and EMI shielding

Developing flexible electronics that integrate multimodal sensing, bias-free signal generation, and electromagnetic interference (EMI) shielding is critical for wearable health monitoring, artificial intelligence, and human-computer interaction. Semiconducting Mo₂TiC₂T_x MXene films show promise for flexible thermoelectrics and EMI shielding, but their relatively low electrical conductivity restricts both the power factor (PF) and the overall EMI shielding effectiveness (SE). Here, we report a van der Waals heterostructure film of Mo₂TiC₂T_x/TaS₂, fabricated via intercalation-exfoliation followed by vacuum-assisted filtration. The heterointerface engineering simultaneously enhances thermoelectric performance and EMI shielding. The electricalconductivity reaches 878.3 S cm⁻¹ (~23-fold enhancement), and the PF reaches 14.4 μW m⁻¹ K⁻² (~4-fold), while the EMI SE improves from 14.1 to 40.6 dB. The film enables dual-mode sensing free from crosstalk, temperature detection via the Seebeck effect and pressure sensing via piezoresistive response, as well as maintaining stable signal fidelity under external EMI. Furthermore, the film exhibits photothermoelectric and Joule-heating responses. Integrated with a wireless acquisition module for signal readout and transmission, the sensor enables real-time transmission of temperature and pressure signals. This work provides a strategy for designing flexible heterostructures that synergistically combine bias-free signal generation, multimodal sensing, EMI resilience, and multi-stimulus responsiveness for next-generation smart electronics.