It is demonstrated that spacer fabrics made of polyester can be coated with Al-doped ZnO (AZO) as thermoelectric (TE) material and conductive silver as contact material to enable smart textiles. An atomic layer deposition process was used for the AZO coating and the conductive silver paste was manually applied. A TE generator and cooling based on the Seebeck and Peltier effect can be observed if a temperature difference or direct current is applied, respectively. Both effects were proven to exist and evaluated. The Seebeck coefficient was determined of up to 50 µ V · K ⁻¹ and a TE power of about 0.2 µ W was generated. Without additional active heat dissipation or cooling, a temperature difference between both spacer fabric surfaces of up to 12 K was achieved. By changing the polarity of the electrical contacts it can significantly be shown that the cold-warm side is changed, as expected for a Peltier element. We observed experimentally the Peltier effect using a single element as well as electrically interconnected sample pairs, the latter could be important for the cooling application. Additionally, the heat transport through the spacer fabrics was tested and showed that there is no heat equalization between the surfaces via air and filaments at temperatures up to 50 °C. The Peltier effect as a fundamental TE effect, that enables site-specific and on-demand cooling applications, has not yet been comprehensively investigated using spacer fabrics and AZO as TE material. These investigations predict that AZO on spacer fabrics hold the special potential to enable flexible and textile solid-state cooling applications.

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.

We report on the fabrication of spherical Au spheres by pulsed laser treatment using a KrF excimer laser (248 nm, 25 ns) under ambient conditions as a fast and high throughput fabrication technique. The presented experiments were realized using initial Au layers of 100 nm thickness deposited on optically transparent and low cost Borofloat glass or single-crystalline SrTiO₃ substrates, respectively. High (111)-orientation and smoothness (RMS ≈ 1 nm) are the properties of the deposited Au layers before laser treatment. After laser treatment, spheres with size distribution ranging from hundreds of nanometers up to several micrometers were produced. Single-particle scattering spectra with distinct plasmonic resonance peaks are presented to reveal the critical role of optimal irradiation parameters in the process of laser induced particle self-assembly. The variation of irradiation parameters like fluence and number of laser pulses influences the melting, dewetting and solidification process of the Au layers and thus the formation of extremely well shaped spherical particles. The gold layers on Borofloat glass and SrTiO₃ are found to show a slightly different behavior under laser treatment. We also discuss the effect of substrates.