Upcycling Silicon Photovoltaic Waste into Thermoelectrics

Abstract

Two decades after the rapid expansion of photovoltaics, the number of solar panels reaching end‐of‐life is increasing. While precious metals such as silver and copper are usually recycled, silicon, which makes up the bulk of a solar cells, goes to landfills. This is due to the defect‐ and impurity‐sensitive nature in most silicon‐based technologies, rendering it uneconomical to purify waste silicon. Thermoelectrics represents a rare class of material in which defects and impurities can be engineered to enhance the performance. This is because of the majority‐carrier nature, making it defect‐ and impurity‐tolerant. Here, the upcycling of silicon from photovoltaic (PV) waste into thermoelectrics is enabled. This is done by doping 1% Ge and 4% P, which results in a figure of merit (zT) of 0.45 at 873 K, the highest among silicon‐based thermoelectrics. The work represents an important piece of the puzzle in realizing a circular economy for photovoltaics and electronic waste.

Physics-guided co-designing flexible thermoelectrics with techno-economic sustainability for low-grade heat harvesting

“…Our delivered strategy, which realized cost-effective, high-output, f-TEs, is facile, universal, and fundamentally different from traditional approaches. In recent years, although the material cost of TE devices has been reduced by using abundant elements (e.g., Mg 3 Sb 2 , SnS, SnSe, half-Heusler compounds, silicide, and polymers) ( 5 , 9 , 14 , 51 – 55 ), the industrialization remains challenging. Since no headway has been made so far in their corresponding large-scale production process, and their demands/markets are unclear ( 33 , 56 ), academia and industry are urged to diversify their research focus past the one-and-only commercialized room temperature Bi 2 Te 3 materials.…”

Recycling of Discarded Photovoltaic Solar Modules for Metal Recovery: A Review and Outlook for the Future

“…11 The value-added conversion of EoL Si from PVs to thermoelectric was carried out by doping (1% Ge and 4% P) followed by spark plasma sintering (1150 °C, 5 min, 50 MPa). 84 An integrated crystalline silicon cell regeneration process was developed by nondestructive cell recovery, wafer prepurification, ultrapurification, and texturing. 76 However, the reutilization of cells is not straightforward.…”

Integrating recyclable polymers into thermoelectric devices for green electronics

“…[36][37][38][39][40][41] However, besides zT, the overall performance of a TEG also depends on other factors such as the quality of electrical and thermal contacts. [42][43][44][45][46][47][48] Therefore, the device encapsulation matrix plays a key role, not only in supporting the mechanical robustness and imparting exibility but also as a ller for the thermal and electrical insulation of the nal device. [49][50][51] Traditionally, once these devices are integrated, it is very tedious to separate the exible polymer matrix from the inorganic TE legs.…”