A multidisciplinary team of engineers at Stanford University, United States, have announced a new type of thin solar cell that uses plasmonics – an emerging branch of science and technology that studies the interaction of light and metal – to more effectively trap light within thin solar cells, an advance that could offer a new direction for the field. Plasmonics, under precise circumstances, can create interactions between light and metal that create a flow of high-frequency, dense electrical waves rather than electron particles. According to Mike McGehee, an associate professor of materials science and engineering, “[P]lasmonics makes it much easier to improve the efficiency of solar cells. Using plasmonics we can absorb the light in thinner films than ever before. The thinner the film, the closer the charged particles are to the electrodes. In essence, more electrons can make it to the electrode to become electricity.” The new solar cell has a honeycomb pattern of nanoscale dimples, each about 300 nanometers in diameter and 200 nanometers tall, that have been imprinted into a layer of silver within the solar cell. The bumpy layer of silver has two benefits: it acts as a mirror, scattering unabsorbed light back into the light-sensitive dye for another shot at collection; and, the light interacts with the silver nanodomes to produce a plasmonic effect. Thin film solar cells still have challenges, particularly in efficiency and durability, but an advance like plasmonics could help take the field down a new and exciting path. The article can be viewed online at the link below.
http://news.stanford.edu/news/2011/january/inexpensive-solar-cells-013111.html