Technology improvements leading to increased efficiency have been rare in the solar energy sector. The efficiency of solar cells has remained at around 20 per cent for a long time now. However, researchers across the globe continue to work hard to develop new solar technologies. Renewable Watch shares a few futuristic technologies that will shape the solar energy sector going forward…
Solar cells that work at night
Researchers at the University of California, Davis, have come up with a solar cell that can work at night. The researchers, Jeremy Munday and Tristan Deppe, have designed a unique solar cell that can generate up to 50 W of solar power per square meter under ideal conditions at night. This is about a quarter of what a conventional solar cell can generate during daytime. According to Munday, the process is similar but reverse of how a normal solar cell works. A regular solar cell generates power by absorbing sunlight, which causes a voltage to appear across the device and for current to flow. In these new devices, light is instead emitted, and the current and voltage go in the opposite direction, generating power.
The device could work during the day as well if it is kept away from direct sunlight or is not facing the sun. Given the adaptability of the device, it can serve as a viable option for balancing the power grid over the day-night cycle.
Cell efficiency using thin-film solar cell can reach 25 per cent
Researchers from the Hasselt University, Interuniversity Microelectronics Centre, Flemish Institute for Technological Research, EnergyVille, and PERCISTAND consortium claim to have achieved a 25 per cent efficiency using a thin-film solar cell. The group of researchers is now targeting to achieve 30 per cent efficiency within the next three years. The solar cells developed by the researchers are made from a paper-thin flexible material and can be used for developing solar panels of all colours and sizes; these can be integrated into facades and roofs of homes.
17 per cent power conversion efficiency in organic photovoltaic cells now possible
While organic photovoltaic (OPV) cells have previously yielded power conversion efficiency greater than 16 per cent, they were made with a spin-coating method in laboratories and were not suitable for large-scale production. Due to the high spinning speed during the spin-coating process, wet films dried too fast, increasing the volatilisation rate of the solvent. This affects the efficiency of the solar cell. And attempting this through any other method would make it challenging to manufacture highly efficient OPV cells.
A team of researchers at the Chinese Academy of Sciences has developed a technique that could increase the power conversion efficiency of OPV solar cells to 17 per cent.
Researchers develop technology that could reduce the cost of high-efficiency solar cells
Scientists at St. Petersburg University in Russia have tested a new technology for the fabrication of high-efficiency solar cells based on A3B5 semiconductors integrated on a silicon substrate. A3B5 compounds are almost equivalent of silicon and germanium by their elector-physical properties. According to scientists, this technology could increase efficiency of the existing single-junction PV converters by 1.5 times. They have shown that A3B5 structures can be grown on an inexpensive silicon substrate, thereby helping to reduce the price of multi-junction solar cells.
National Renewable Energy Laboratory develops lead absorbing technology for solar perovskite cells
Perovskite solar cell is an emerging technology with great potential for the solar industry. However, it still faces certain environmental hazards regarding lead toxicity, which is impeding its wider adoption. While the chances are slim, there is always a possibility of lead leakage when using this technology; this could pose serious health risks.
Researchers at the National Renewable Energy Laboratory have come up with a technology that could sequester the quantity of lead used in developing perovskite solar cells. They have also developed a chemical approach to avoid 96 per cent of the lead leakage caused by severe device damage.
To prevent the leakage of lead in case the cell is damaged, the researchers at NREL coated both sides of the cell with lead absorbing films, and then cut the cell into half. They dipped the damaged cell in water and found that the lead absorbing film can prevent nearly 96 per cent of lead from leaking into the water from the damaged cells. Moreover, the addition of the film on the cell did not decrease the efficiency of the perovskite cells. This is a positive result and will help in the greater use of such cells.