Enhanced Stability of TaS ₂ Photodetector by Co Intercalation

Two-dimensional transition-metal dichalcogenides hold great potential for next-generation optoelectronic devices. However, their atomic-scale thickness renders them highly susceptible to molecular adsorption, severely compromising device stability. In this study, we demonstrate a significant enhancement in the stability of the photoelectric response of 2 H -TaS 2 nanoflakes through cobalt (Co) intercalation. While intrinsic devices exhibit a rapid degradation of 20.5% within hours, the Co-intercalated device shows negligible degradation, demonstrating markedly improved photochemical stability. Remarkably, the photoresponsivity remains at 98.8% of its initial value after two months, projecting an operational lifespan of ∼9.4 years. Moreover, intercalation enhances device performance by more than doubling the responsivity. The intercalated atoms are suggested to prevent the ingress of water and oxygen molecules into the interlayer spaces, thereby enhancing resistance to photochemical reactions and oxidation-induced degradation. This work presents an effective strategy for improving the stability of two-dimensional optoelectronic devices.