Nanomechanical properties and wear resistance of Palladium diselenide (PdSe₂) for flexible electronics

Palladium diselenide (PdSe₂), a transition-metal dichalcogenide (TMDC), has received interest for its intriguing optical and electrical characteristics. Despite its relevance for flexible electronics, its mechanical properties have been only scarcely investigated. In this work, we examined time-dependent mechanical response, wear, and nanoductility of PdSe₂ grown using chemical vapor transport. Specifically, we measured hardness, elastic modulus, creep characteristics, activation volume, strain rate sensitivity, and wear resistance using nanoindentation and nanoscratch experiments. The obtained values of Young's modulus and hardness are promising for flexible electronic applications. Due to its strain hardening and strain-rate sensitivity, PdSe₂ is ductile like aluminum and could endure significant deformation without losing structural integrity. The investigation of the creep behavior showed its size-dependent mechanical endurance under steady load, which is important for device dependability. Additionally, activation volume calculations indicate dislocation dynamics and processes during deformation, revealing the material's reaction to different mechanical loading conditions. Our nanoscratch experiments showed resilience to surface wear, confirming its suitability for durable flexible electronic devices. The significant elasticity of PdSe₂, facilitating substantial recovery after deformation, renders it well-suited for flexible and wearable electronic devices requiring the maintenance of electrical continuity even under mechanical stress. The results of our mechanical characterization will open the door to the design and manufacturing of next generation PdSe₂-based flexible electronic devices.