Two decades after the rapid expansion of photovoltaics, the number of solar panels reaching the 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 cell, 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 is a rare class of material in which defects and impurities can be engineered to enhance its performance. This is thanks to its majority carrier nature, making it defect- and impurity-tolerant. Here, we enables the upcycling of silicon from photovoltaic waste into thermoelectrics. This is done by doping 1% Ge and 4% P, which results in figure of merit (zT) of 0.45 at 873 K, the highest amongst silicon-based thermoelectrics. Our work represents an important piece of puzzle in realizing circular economy for photovoltaics and electronic waste.
This article is protected by copyright. All rights reserved