Unraveling the Synergistic\nRole of Kinks in Zig-Zag\nAg<sub>2</sub>Se Nanorod Arrays for High Room-Temperature zT and Improved\nMechanical Properties: Experimental and First-Principles Studies

Flexible thermoelectric materials are usually fabricated\nby incorporating\nconducting or organic polymers; however, it remains a formidable task\nto achieve high thermoelectric properties comparable to those of their\ninorganic counterparts. Here, we present a high zT value of 1.29 ±\n0.31 at room temperature in the hierarchical zig-zag Ag<sub>2</sub>Se nanorod arrays fabricated using the glancing angle deposition\n(GLAD) technique followed by a facile selenization process. The high\nzT value at 300 K is ascribed to the ultrahigh power factor of 3101\n± 252 μW/m-K<sup>2</sup> and the reduced thermal conductivity\nof 0.72 ± 0.01 W/mK. Based on <i>ab initio</i> computational\nand experimental evidence, we reveal that kinked Ag<sub>2</sub>Se\nnanorod arrays consisting of rough interfaces modulate the lattice\nthermal conductivity up to 48.5% at room temperature. The modulation\nresults from interchanging of phonon modes at kink points and enhanced\nscattering from a large number of rough interfaces. Further, benefiting\nfrom kinked hierarchy, a notable improvement in the mechanical performance\nis observed for zig-zag Ag<sub>2</sub>Se nanorods which is confirmed\nby nanoindentation measurements. The synergic improvement in thermoelectric\nand mechanical performance not only unravels a paradigm to harness\nthermoelectric heat but also offers deeper insights into tuning the\nmechanical properties of inorganic thermoelectric materials.