Impact of moisture contents on the performance of organic bi-layer ITO/OD thermo-electric cells

We propose a bi-layer thermo-electric cell based on elastic indium tin oxide (ITO) substrate and organic semiconductor orange dye (OD). It is observed that thermo-electric voltages are similar to 30 % higher in bi-layer ITO/OD cell as compared to the single layer ITO cell. This improvement is caused by an obvious increase in Seebeck coefficient, which could be related to the appropriate electrical and thermal conductivities of the bi-layer organic thermo-electric cell. The effect of moisture contents on the Seebeck coefficient of the ITO/OD based bi-layer thermo-electric cell has also been investigated. The experimental results clearly show that with the increase of temperature Seebeck coefficient increases, whereas with increasing moisture contents the Seebeck coefficient of the ITO/OD thermo-electric cell significantly decreases. Our results point out the need for well-controlled environmental conditions, predominantly moisture level, in order to appraise the thermo-electric performance of organic semiconductor materials.