The integration of electronic functionalities into textiles for use as wearable sensors, energy harvesters, or coolers has become increasingly important in recent years. A special focus is on efficient thermoelectric materials. Copper iodide as a p-type thermoelectrically active, nontoxic material is attractive for energy harvesting and energy generation because of its transparency and possible high-power factor. The deposition of CuI on polyester spacer fabrics by wet chemical processes represents a great potential for use in textile industry for example as flexible thermoelectric energy generators in the leisure or industrial sector as well as in medical technologies. The deposited material on polyester yarn is investigated by electron microscopy, x-ray diffraction and by thermoelectric measurements. The Seebeck coefficient was observed between 112 and 153 µV/K in a temperature range between 30 °C and 90 °C. It is demonstrated that the maximum output power reached 99 nW at temperature difference of 65.5 K with respect to room temperature for a single textile element. However, several elements can be connected in series and the output power can be linear upscaled. Thus, CuI coated on 3D spacer fabrics can be attractive to fabricate thermoelectric devices especially in the lower temperature range for textile medical or leisure applications.

Bi_1−xTe_x-compounds are among the most commonly used thermoelectric materials due to their high Seebeck coefficient, high electrical conductivity and low thermal conductivity at room temperature. N-type Bi_1−xTe_x-thin films for thermoelectric applications were deposited onto glass substrates by electron beam co-evaporation. The thin films cover the range of x = 0.57–0.66. In this study, the influence of the stoichiometry on the Seebeck coefficient, electrical conductivity and the derived power factor for as-deposited thin films is investigated. The results show a maximum power factor of 310 μW m⁻¹ K⁻² for x = 0.59. All samples were annealed to a maximum temperature of 350 °C in steps of 50 °C for 10 h each and the thermoelectric properties were measured after each annealing step. A significant improvement for the thermoelectric properties of the samples was achieved with thermal annealing at 300 °C resulting in a maximum power factor of about 1800 μW m⁻¹ K⁻².