Wearable solar thermoelectric generators could become a common item of your wardrobe in the future. These generators could power an array of devices, from smartphones to smart glasses, capturing energy that would be lost in the form of heat, light, sound, vibration, or movement. The new development with the technology signals a new means to further improve the efficiency by raising the temperature difference.
The research has been led by Professor Kyoung Jin Choi in the School of Materials Science and Engineering, who works at the Ulsan National Institute of Science and Technology. Choi’s device works on the basis of a temperature difference occurring between the hot and cold sides. Through variations with the technology, the temperature difference can be increased as high as 20.9 °C. This differential is considerably higher than the typical temperature differences of 1.5 to 4.1 °C with currently wearable thermoelectric generators that are driven by body heat.
The generators convert heat flux (that is, temperature differences) directly into electrical energy through a physical phenomenon called the Seebeck effect (where the conversion happens at the junction of different types of wire). On a big scale these types of generators are being considered for use in power plants to convert waste heat into additional electrical power.
To make generators far more efficient, Professor Choi’s team fitted a local solar absorber onto a substrate. The solar absorber was a a five-period Ti/MgF2 superlattice, where each of the five layers enabled the optimal absorption of sunlight. This led to a rise in the temperature difference, sufficient to operate an array of self-powered wearable electronic devices.
The following video summarizes the process:
The new research has been published in the journal Nano Energy, with the research paper titled “Wearable solar thermoelectric generator driven by unprecedentedly high temperature difference,”
