webcasts2009 Finalist :: Mei-Ling Kuo
 |
Mei-Ling Kuo
Department of Physics, Applied Physics, and Astronomy
Mei-Ling Kuo's innovation could bring the world a step closer to realizing efficient, cost-effective solar energy harvesting. Her new antireflective coating overcomes two major hurdles hampering the development and more widespread use of solar panels for power generation.
By stacking seven layers of carefully calibrated nanorods on top of one another, Kuo has developed an antireflective coating that boosts the amount of sunlight captured by solar panels and allows those panels to absorb the entire solar spectrum from nearly any angle. The new coating is relatively easy and inexpensive to produce, and its application can be seamlessly built into existing solar cell manufacturing processes.
Untreated silicon solar cells only absorb 67.4 percent of sunlight shone upon them, meaning that nearly one-third of that sunlight is reflected away and thus unharvestable. From an economic and efficiency perspective, this unharvested light is simply wasted potential. A silicon surface treated with Kuo's new antireflective coating, however, absorbs 96.21 percent of sunlight shone upon it, and only 3.79 percent of the sunlight is reflected and unharvested. Her calculations show that this jump in absorption should translate into a 22-percent increase in solar-to-electric power conversion.
Kuo's new antireflective coating is the first such coating to absorb the entire light entire spectrum of sunlight, from UV to visible light and infrared, regardless of the sun's position in the sky. She used different deposition techniques to stack seven layers of silicon dioxide and titanium dioxide nanorods, positioned at oblique angles. Each layer looks and functions similar to a dense forest where sunlight enters but cannot exit once it is "captured" in the maze of trees.
Each layer of Kuo's new antireflective coating has a different refractive index, meaning it is tuned to reflect a certain range of wavelengths. Stacked on top of each other, these layers enhance the antireflective properties of the underlying layers, creating an effect that "bends" the flow of sunlight to a particular angle, and in turn increases the coating's overall effectiveness. Each layer helps to capture any light that may have otherwise been reflected off of the layers below it.
This ability to capture the entire spectrum of sunlight from any angle could lead to the development of a new generation of stationary solar panel arrays. Many solar panel arrays in use today are mechanized to slowly move throughout the day so their panels are perfectly aligned with the sun's position in the sky, to ensure maximum efficiency. Stationary arrays would likely be less expensive to build, manage, and upkeep.
Since joining the Rensselaer Department of Physics, Applied Physics, and Astronomy in 2007, Kuo has co-authored a journal paper and has a patent pending for her broadband antireflective coating.
Interested in science and technology from a young age, Kuo excelled at academics throughout middle and high school in her hometown of Taipei, Taiwan. Her parents, now retired, along with her older and younger brothers have been supporting of her move to the United States and investigations into cutting-edge antireflective and solar cell technologies.
Kuo earned her bachelor's degree in physics from National Taiwan Normal University, attended the University at Buffalo, and is currently working toward her master's degree and doctorate in physics at Rensselaer.
