Structural Modifications and Enhanced Thermoelectric Performance of CuI Nanoparticles Induced via Al-Doping

Thermoelectric (TE) materials are of great importance for harvesting thermal energy from waste or solar heat. One of the promising TE materials is copper iodide (CuI), which is nontoxic, earth-abundant, and has a high Seebeck coefficient at room temperature (RT). The TE performance of CuI nanoparticles (NPs) is found to be further enhanced by appropriate Al-doping through reducing the particle size and simultaneously enhancing the electrical conductivity by a factor of 10. Al-doping manifests to enlarge the deviation from stoichiometric composition, namely delta in Cu1-delta I, and can further assist co-doping of iodine to generate carrier holes. The thermal conductivity is also reduced by Al-doping and overall, the figure of merit increases from 0.01 for the pure CuI nanocrystals to approximate to 0.12 at 300 K and approximate to 0.2 at 385 K, respectively, for the 0.23 mol% Al-doped NPs. The power generation characteristics of a single leg TE module made up of the 0.23 mol% Al-doped CuI measured under real-time conditions firmly indicate its suitability as a TE generator operating near RT.

Automated summary

The article introduces the improved thermoelectric performance of copper iodide nanoparticles through appropriate aluminum doping. Aluminum doping enhances the electrical conductivity and reduces the particle size, leading to enhanced thermoelectric efficiency. The doped nanoparticles also show enhanced power generation capabilities near room temperature.