Researchers at US-based RTI International have developed a new technology that could make solar energy considerably more affordable, thereby speeding up its market adoption. The company’s solar cells, formed from solutions of semiconductor particles known as colloidal quantum dots, reportedly have a power conversion efficiency comparable to that of conventional cells at a fraction of the cost.
Solar energy has the potential to be a globally significant carbon-neutral source of electricity but the high cost of photovoltaics – the devices that convert sunlight into electricity – has slowed widespread adoption of this resource. The RTIdeveloped solar cells were created using low-cost materials and processing techniques that reduce the primary costs of photovoltaic production, including materials, capital infrastructure and the energy associated with manufacturing.
Preliminary analysis of the material costs of the technology show that it can be produced for less than R160 per square metre – as much as 75 per cent less than traditional solar cells.
Says Ethan Klem, a research scientist at RTI and co-principal investigator of the project: “Solar energy currently represents less than 1 per cent of percent of the global energy supply, and substantial reductions in material and production costs of photovoltaics are necessary to increase the use of solar power. This technology addresses each of the major cost drivers of photovoltaics and could go a long way in helping achieve that goal.”
In demonstration tests, the cells consistently provided a power conversion efficiency exceeding 5 per cent, which is comparable to other emerging photovoltaic technologies. The cells are composed of lightweight, flexible layers and have the potential to be manufactured using high-volume roll-to-roll processing and inexpensive coating processes, which reduces capital costs and increases production output.
When an asteroid absorbs sunlight and emits that energy as heat, the space rock changes trajectory slightly. This Yarkovsky effect produces a force of only 14 g per incident, but it accumulates over time. The team behind Nasa’s OSIRIS-REx craft, which is due to rendezvous with asteroid 1999 RQ36 in 2019, has been calculating the rock’s orbit to ensure a safe landing. In the past 12 years, the effect has pushed the 61 million-ton asteroid 160 km off-course. – AH