Development, experimental and simulated performance of copper iodide (γ-CuI) uni-track thin film thermoelectric modules

In this article, we investigate the performance of 950 nm thick p-type γ-CuI uni-track thin film thermoelectric modules. A model was first developed to optimize a module’s geometry, focusing on the length and the number of the γ-CuI tracks. Based on the maximum power achieved and the open circuit voltage (above 225 mV), the simulation optimized module consists of three tracks of γ-CuI, each with a length of 13 mm. Using these simulation results, modules were elaborated through solid iodination process of Cu thin tracks. These γ-CuI tracks were then connected with Pt electrodes. After characterizing the structure and electrical properties of the γ-CuI material, the module’s performance was measured at various applied temperatures in a free gradient mode. The results were in agreement with the simulation. Experimental and simulated performances highlight the significant impact of contact resistance as the temperature increases limiting module performances. A maximum power of 61nW was achieved at an applied temperature of 190 °C. This suggests that higher values could be attained through optimized contacts, with the goal of enabling some commercial applications for easily manufactured modules. Due to the optoelectrical properties of γ-CuI, this even paves the way for the development of new transparent thermoelectric generators.