American put-call parity arbitrage : Nikkei 225 index futures and options (intraday bid-ask quotation from Jan-Oct 2000).

Various studies were conducted to the index arbitraging. Our study on Nikkei 225 arbitraging based on put-call parity has no precedent. We concluded that arbitrage opprtunity in Nikkei 225 index derivatives market in SGX-DT is limited after taken into consideration of the practical trading constraint

Upcycling silicon photovoltaic waste into thermoelectrics

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.Agency for Science, Technology and Research (A*STAR)Ministry of National Development (MND)National Environmental Agency (NEA)A.S. acknowledges funding from A*STAR (Agency of Science, Technology and Research) Career Development Fund (CDF) no. C210112022. J.X acknowledges A*STAR “Sustainable Hybrid Lighting System for Controlled Environment Agriculture programme”: A19D9a0096. Z.L. would also like to express gratitude to the financial support from the A∗STAR’s Science and Engineering Research Council (SERC) Central Research Fund (Use-inspired Basic Research) for this work. N.M. and Q.Y. acknowledge grant award from NEA (National Environmental Agency, Singapore) and Ministry of National Development (MND, Singapore) titled “Singapore–CEA Alliance for Research in Circular Economy (SCARCE, award number USS-IF-2018-4),” which is a joint lab set up between Nanyang Technological University (NTU, Singapore) and the French Alternative Energies and Atomic Energy Commission (CEA, France)