Fabrication of flexible thermoelectric generators with a lens array for near-infrared solar light harvesting

A flexible thermoelectric generator with a lens array that converts near-infrared (NIR) solar light, was fabricated using lithography and thin-film deposition processes. The generator comprised serially connected 270 pairs of thin-film thermocouples and a polydimethylsiloxane (PDMS) lens array. It possessed the flexibility to be easily placed on glass windows. The thermoelectric elements of Cu (p-type) and Cu-Ni (n-type) thin films were used in thermoelectric generators. The thermoelectric thin films were deposited on flexible polyimide substrates using sputtering method and were formed using lift-off techniques. When solar light (A.M. 1.5) was irradiated onto the fabricated generator, the open-circuit voltage and the maximum power were 7.4 V/m
²
and 11 μW/m
²
respectively. The flexible thermoelectric generator can be placed on arbitral hard materials, such as glass windows, for energy harvesting.