Flexible Hybrid Photo-Thermoelectric Generator Based on Single Thermoelectric Effect for Simultaneously Harvesting Thermal and Radiation Energies

Abstract

Wearable electronic devices have great potential in the fields of the Internet of Things (IoT), sports and entertainment, and healthcare, and they are essential in advancing the development of next-generation electronic information technology. However, conventional lithium batteries, which are currently the main power supply of wearable electronic devices, have some critical issues, such as frequent charging, environmental pollution, and no surface adaptability, which limit the further development of wearable electronic devices. To address these challenges, we present a flexible hybrid photothermoelectric generator (PTEG) with a simple structure composed of a thermoelectric generator (TEG) and a light-to-thermal conversion layer to simultaneously harvest thermal and radiation energies based on a single working mechanism. The mature mass-fabrication technology of screen printing was applied to successively prepare n-type (i.e., Bi 2 Te 2.7 Se 0.3 ) and p-type (i.e., Sb 2 Te 3 ) thermoelectric inks atop a polyimide substrate to form the TEG with a serpentine thermocouple chain, which was further covered by a light-tothermal conversion layer to constitute the PTEG. The resulting PTEG with five pairs of thermocouples generated a direct-current output of 82.4 mV at a temperature difference of 50 °C and a direct-current output of 41.2 mV under 20 mW/cm 2 infrared radiation. Meanwhile, the remarkable mechanical reliability and output stability were experimentally demonstrated through a systematic test, which indicated the feasibility and potential of the developed PTEG as a reliable power source. In addition, as desirable application prototypes, the fabricated PTEGs have been successfully demonstrated to harvest biothermal energy and infrared radiation to drive portable electronic devices (e.g., a calculator and a clock). Hybrid energy harvesting technology based on a simple structure may provide a new solution to current power supply issues of wearable electronic device.

Ag2Se/nylon self-supporting composite films for wearable photo-thermoelectric generators with high output characteristics

“…43 A very high output power of 8.3 and 15.8 mW can be reached when this PTEG is irradiated with light intensities of 100 and 150 mW cm À2 , respectively. The power enhancement of the PTEG can be easily obtained by increasing the number of legs, so the singleleg output power of 2.1 and 4.0 mW with light intensities of 100 and 150 mW cm À2 of this device is used to compare it with the vast majority of the currently reported PTEGs, 13,40,42,43,[56][57][58] as shown in Fig. 5g.…”

“…(e) Output voltage and (f) power versus current at different NIR light radiation powers. (g) Comparison ofthe single-leg output power of the PTEG in our work with that in reported studies 13,40,42,43,[56][57][58]. (h) Open-circuit output voltages of the device at different intensities of visible light irradiation.…”

“…A photo-thermoelectric generator (PTEG) is a new model of an energy harvester proposed in recent years, which is based on TE materials and introduces the photothermal (PT) step, thus enabling the process of regenerating electrical energy from the heat generated by light. [40][41][42] A signicant advantage is that the traditional heat convection and conduction can not only be applied to generate electricity in a light-free environment just like ordinary TE materials, but it can also take advantage of the neglected thermal radiation from ambient light sources (such as sunlight) to create an effective temperature difference for TE devices to generate electricity. Depending on the location where the PT and TE effects occur, PTEGs are divided into heterogeneous asynchronous and homogeneous synchronous devices.…”

Viscoelastic Liquid from Regenerated Silk Fibroin in the Silk I Conformation: A Writeable and Shapeable Material

“…However, silk I converts to a β-sheet-rich silk II conformation due to the effect of organic solvents, temperature, shear stress, pH, and concentration, which causes the final material to be stiff with high tensile strength and slow degrading nature. − Yu et al showed that RSF undergoes conformational alteration at a shallow concentration (0.1 mg mL –1 ) and suggested a nucleation-dependent aggregation process that involved the shear-induced transition of the random coil to the β-strand, which further converts into β-sheets . RSF has been processed in different forms of materials, e.g., hydrogels, sponges, films, fibril-based mats, nanoparticles, and especially silk fibroin films have been extensively used in electronics. − RSF-based films have been made using spin coating and dry casting techniques, where the dry-cast films are mechanically less robust and brittle and the spin-coated films provide better mechanical toughness (∼32 kJ m –3 ) with an ultimate tensile strength of 100 MPa but still with a high degree of brittleness (breaking strain was found in between 0.5 and 3%). This limits their applicability in (human bone marrow stromal cells) growth and attachment. ,,− Furthermore, RSF-based hydrogels have been fabricated via sol–gel transformation induced via various methods including sonication, heat/cold treatment, osmotic stress, and pH.…”

Experimental and Theoretical Investigation of the Effect of Filler Material on the Performance of Flexible and Rigid Thermoelectric Generators

“…The electrical energy can be from as low as nanowatts to a few watts, making it suitable for a wide range of applications. Some of the applications include the following: in space, integration with gas turbine, standalone solar TEG, combined with photovoltaic to generate additional electrical energy, , and powering of portable electronic devices − and wearable sensors. − Thermoelectric generators are lightweight, can be rigid or flexible, and operate quietly day and night since they do not have moving parts. Additionally, they have no gas emission, no vibration, and a long lifespan .…”