| Summary: | Surface-modified nanoplate-shaped thermoelectric materials can achieve good thermoelectric performance. Herein, single-crystalline Bi<sub>2</sub>Te<sub>3</sub> nanoplates with regular hexagonal shapes were prepared via solvothermal techniques. Surface modification was performed to deposit different metals onto the nanoplates using electroless deposition. Nanoparticle-shaped tin (Sn) and layer-shaped palladium (Pd) formed on the Bi<sub>2</sub>Te<sub>3</sub> nanoplates via electroless deposition. For the sequential deposition of Sn and Pd, the surface morphology was mostly the same as that of the Sn-Bi<sub>2</sub>Te<sub>3</sub> nanoplates. To assess the thermoelectric properties of the nanoplates as closely as possible, they were compressed into thin bulk shapes at 300 K. The Sn-Bi<sub>2</sub>Te<sub>3</sub> and Sn/Pd-Bi<sub>2</sub>Te<sub>3</sub> nanoplates exhibited the lowest lattice thermal conductivity of 1.1 W/(m·K), indicating that nanoparticle-shaped Sn facilitated the scattering of phonons. By contrast, the Pd-Bi<sub>2</sub>Te<sub>3</sub> nanoplates exhibited the highest electrical conductivity. Thus, the highest power factor (15 μW/(m∙K<sup>2</sup>)) and dimensionless <i>ZT</i> (32 × 10<sup>−3</sup>) were obtained for the Pd-Bi<sub>2</sub>Te<sub>3</sub> nanoplates. These thermoelectric properties were not as high as those of the sintered Bi<sub>2</sub>Te<sub>3</sub> samples; however, this study revealed the effect of different metal depositions on Bi<sub>2</sub>Te<sub>3</sub> nanoplates for improving thermoelectric performance. These findings offer venues for improving thermoelectric performance by sintering nanoplates deposited with appropriate metals.
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