Solar energy is one of the most effective ways to generate electricity without carbon emissions, but silicon-based solar panels are approaching a limit on their efficiency. Caelux, which emerged from the California Institute of Technology in 2014, hopes to improve the performance of silicon by coating the glass that covers it with a thin layer of perovskite, a material that generates energy from a different part of the light spectrum.
In the 1960s, the semiconductor researchers William Shockley and Hans-Joachim Queisser estimated that the efficiency of solar panels made of a single material would top out at about 30% because they absorb only a portion of the light spectrum and lose some energy to heat. One way to move beyond this limit is to build solar panels with multiple materials.
Perovskite is good at absorbing shorter wavelengths of light, while silicon is better at absorbing longer wavelengths. When used together, the two materials absorb a wider portion of the light spectrum than when either is used alone, improving efficiency.
According to the US National Renewable Energy Laboratory (NREL), the best commercial silicon-based solar cells are about 24% efficient, near the Shockley-Queisser limit. The NREL analysis shows that tandem perovskite-silicon solar panels have achieved more than 30% efficiency. Caelux aims to scale the technology to work with commercial solar panels.
In September, Reliance Energy invested $12 million in Caelux and hopes to use the technology at a manufacturing hub in India. Caelux isn’t the only company pursuing perovskite solar materials. Last year, CubicPV raised $25 million and Swift Solar raised $8 million to develop solar panels using perovskite.
Nearly a third of the food grown on farms is wasted, according to the United Nations’ Food and Agriculture Organization. Chinova Bioworks is developing a natural preservative made from the antimicrobial polymer chitosan to address that problem.
Chitosan, which also has pharmaceutical and industrial uses, is often sourced from the shells of crustaceans, but Chinova extracts the material from discarded mushroom stems. The company says the approach makes it easier to incorporate chitosan into foods because it’s vegan and unlikely to cause an allergic reaction.
Chinova, founded in Canada in 2016, argues that customers are wary of artificial preservatives and that the natural products currently available aren’t very effective. For example, the natural preservative natamycin is effective only against yeast and fungi, while nisin usually works only on gram-positive bacteria, which have simple cell walls. Chinova claims that its chitosan-based preservative kills all those microbes, as well as gram-negative bacteria, which have more complex cell walls.
After securing seed funding from the venture arm of the food ingredient giant DSM in 2018, Chinova raised $6 million in series A funding in June 2022. The US Food and Drug Administration subsequently sent the company a letter raising no questions about the preservative’s status as generally recognized as safe. The company also expanded its facility on Prince Edward Island, increasing production by a multiple of 20, it says. Chinova aims to sell its preservative to companies making beverages, sauces, dairy, plant-based dairy, plant-based meats, and baked goods.
Chemical firms are increasingly focused on their environmental impact. Cinthesis promises to help them use mechanical force, rather than high temperatures and solvents, to drive chemical reactions, an approach called mechanochemistry.
The company’s technology is based on research from James Mack, a University of Cincinnati chemist, and Joel Andersen, a former graduate student in Mack’s lab; they are now helping lead the organization. Cinthesis uses a souped-up version of a ball mill, essentially a spinning drum with steel balls inside, to study the fundamentals of chemical reactions at laboratory scale. The company’s innovation is controlling the temperature of the ball mill, which makes it easier to gather the necessary information to run larger-scale reactions.
Cinthesis scales up to producing kilogram quantities by switching to a twin-screw extruder, a pair of rotating screws that grind a material as it is pushed down a temperature-controlled barrel. Those bigger experiments give the firm’s customers the information they need to scale up further to demonstration- or pilot-scale projects. So far, approaches based on mechanochemistry appear to offer environmental benefits, but they have a long way to go before they are commercially producing chemicals.
The company launched in 2020 with seed funding from CincyTech, a public-private venture capital fund that invests in Ohio-based companies. In April 2022, Cinthesis announced that it signed its first contract and is lining up additional customers.
Concrete is one of the most widely used materials on the planet, and producing cement, the glue that holds together the rocks and sand in concrete, is responsible for a whopping 8% of global carbon dioxide emissions, according to a report from the European Commission’s Joint Research Centre.
Cement is normally made by heating limestone, silica-rich clays, and other ingredients to extremely high temperatures, often in kilns heated by fossil fuels, to form calcium silicate aggregates. The minerals are then ground with gypsum into a powdered cement.
Prometheus Materials, which spun out of the University of Colorado Boulder last year, grows microalgae that generate calcium carbonate, which the company turns into a cement. Because the process happens at ambient temperature and pressure, Prometheus says, it produces 90% less CO2 than conventional cement manufacturing while yielding a material with equal or better performance.
In 2016, a team from the University of Colorado Boulder received funding from the US Department of Defense to develop the technology behind Prometheus. And in June of this year, the company raised $8 million in series A financing from Sofinnova Partners, Microsoft’s Climate Innovation Fund, and other investors. Prometheus is using the funding to make concrete cinder blocks, roofing tiles, and other precast building materials, as well as a ready-mix concrete. The firm also plans to use its cement in a pilot-scale demonstration for Microsoft.
Traceless Materials, founded in Germany in 2020 by Anne Lamp and Johanna Baare, is developing a naturally biodegradable plastic material made from corn gluten meal.
Many of today’s biobased plastics, like polylactic acid (PLA), can be composted only in industrial facilities. Moreover, whereas most PLA is made from agricultural crops, such as corn or sugarcane, Traceless uses corn gluten meal generated as a by-product of starch production. The company argues that its feedstock is cheaper and more sustainable than crops grown for food.
The key molecule in Traceless’s plastic is zein, a hydrophobic, film-forming protein found in corn gluten. There are already processes for making zein-based plastic, but they typically require adding plasticizers to make the material less brittle. Traceless achieves flexibility with the fatty acids already in corn gluten meal, keeping costs low.
After using an organic solvent to extract the zein and fatty acids from corn gluten meal, Traceless cools the liquid, precipitating a hard plastic for food packaging or single-use utensils. The remaining liquid can be used to make a flexible plastic film.
Last year, the European Innovation Council, a government investment group, put $2.4 million in Traceless, and the company is using the funding to scale up its technology. Traceless also set up a pilot plant near Hamburg, Germany, and landed several pilot-scale partnerships.