Enhanced Energy Harvesting with a Flexible PEDOT:PSS-Based Photo-Thermoelectric Generator

In the present work, efforts have been made to develop single platform-based flexible photothermoelectric generators (PTEGs); in order to harvest both thermal and radiation energies, PTEGs have a basic structure made up of thermoelectric generators and photothermal conversion layers (PTCLs). The simple drop-cast technique has been employed to prepare an array of 10 TE-legs of a poly(3,4-ethylenedioxythiophene)polystyrenesulfonate (PEDOT:PSS)/Al thermocouple chain with aluminum as the metal contact over a flexible polyamide substrate. The PTCL consists of a photon-trapping layer and a reflecting film for harvesting solar rays to generate temperature gradient in the PTEG device. The photon-trapping layer is composed of graphite combined with polydimethylsiloxane (PDMS), while the photon-reflective layer is made up of TiO 2 in conjunction with PDMS. When exposed to 1 Sun (100 mW/cm 2 ) solar radiation, the conversion layer quickly generated a temperature gradient of 12.6 K in just 250 s in the PTEG device, which yields an output PTE voltage of 4 mV with an optimal output power of 2.96 nW. For the TEG with 10 TE-legs, the peak output voltage was 34 mV and the Seebeck coefficient was determined to be 335 μV/K; concurrently, the maximum value of the power factor (σ S 2 ) calculated was 118.9 mW/mK 2 . Moreover, during the flexibility test, the internal resistance remained consistently stable, demonstrating the outstanding ability of PTEGs to recover from bending. Furthermore, the fabricated PTEGs have been successfully utilized as prototypes for harvesting biothermal and solar energy. This hybrid energy harnessing technology presents a promising method to address challenges faced by wearable electronic devices.