Environment Technology

Hong Kong Develops World’s Most Efficient Solar Cells To Date

Perovskite solar cells

Scientists from the Hong Kong Polytechnic University have reportedly developed perovskite-silicon tandem solar cells that have a power conversion efficiency of 25.5%. This is the record for the world’s highest power conversion from solar cells thus far.

You may have heard Perovskite solar cells mentioned back in 2009. Their efficiency then was a mere 3.9% and years of dedication and vigorous research have finally caused those numbers to multiply more than 6 times to reach the staggering 25.5% achieved just this year. The world has been fighting for a long time for more energy solutions. Researchers around the globe have been hard at work looking for new ways to generate sustainable power more effectively on a wide-scale.

The Department of Electronic and Information Engineering research team is led by Professor Charles Chee Surya. The researchers have claimed this impressive world record with their newfound ability to enhance energy conversion more efficiently than ever. Scientists estimate that solar energy will be generated for HK$2.73/W instead of the present day HK$3.9/W with the help of silicon solar cells being used on the market.

There is more than a single wavelength for solar energy and a variety of materials for making solar cells is most effective for the absorption of energy. Methlylammonium lead tri-halide perovskite and silicon solar cells are used to create a binding pair. The perovskite solar cell works as the top layer, harvesting short wavelength photons. At the same time, the bottom layer is coated with silicon and works to absorb long wavelength photons.

Researchers at Polytechnic University receive the most power out of their power conversions because of their smart approaches to the technology they have been experimenting with for years. The team found that low temperature annealing process within dry oxygen can reduce the impact made by perovskite defects. They then fabricated a multi-layer of molybdenum trioxide, gold and molybdenum trioxide at just the right amount of thickness which became highly transparent so that light could find its way into the very bottom silicon layer underneath the perovskite. Dr. Zijian Zheng of PolyU Institute of Textiles and Clothing then applied a haze film to the very top layer of the solar panel in order to capture and store additional light. When all three of these approaches are combined, the energy conversion efficiency is greatly enhanced.

Professor Shen Hui of Sun Yat-sen University and Shun De SYSU Institute for Solar Energy are to thank for the design and fabrication of this new silicon cell. Their high efficiency cells skyrocket conversion numbers throughout testing. For the time being, research teams at Polytechnic University plan to continue their testing in hopes of improving power conversion efficiency even further into the future. There are plans to take their findings and apply them to a large-scale fabrication of perovskite-silicon solar cells. Such tests could prove to be quite beneficial to the future of our world, as energy consumption numbers show no signs of slowing down.