The new research presents glitter-sized photovoltaic cells, which could turn a person into a walking solar battery charger if they were fastened to flexible substrates molded around unusual shapes, such as clothing. These cells are solar particles, which are fabricated of crystalline silicon. They are fabricated using microelectronic and micro-electromechanical systems (MEMS) techniques common to today’s electronic foundries. Since the researchers expect these particles to be cheaper and more efficient than current photovoltaic collectors, they estimate that the research will get the attention of many firms at the solar-energy industry.
The research’s lead investigator, Greg Nielson from Sandia National Laboratories, said his team has identified more than 20 benefits of scale for its micro-photovoltaic cells. These include new applications, improved performance, potential for reduced costs and higher efficiencies. “Eventually units could be mass-produced and wrapped around unusual shapes for building-integrated solar, tents and maybe even clothing,” he said.
Sandia field engineer, Vipin Gupta, added: “Photovoltaic modules made from these micro-sized cells for the rooftops of homes and warehouses could have intelligent controls, inverters and even storage built in at the chip level.” Therefore, such micro-engineered panels could have circuits imprinted that would help perform other functions customarily left to large-scale construction with its attendant need for field construction design and permits. “Such an integrated module could greatly simplify the cumbersome design, bid, permit and grid integration process that our solar technical assistance teams see in the field all the time,” Gupta concludes.
The cells range from 14 to 20 micrometers thick, making them approximately 10 times thinner than conventional 6-inch-by-6-inch brick-sized cells. However, they perform at about the same efficiency, creating the possibility for more compact, portable applications of solar power. “The shade tolerance of our units to overhead obstructions is better than conventional PV panels,” said Nielson, “because portions of our units not in shade will keep sending out electricity where a partially shaded conventional panel may turn off entirely.”
The new development could benefit large-scale power generation as well. Murat Okandan, a member of the team, said: “One of the biggest scale benefits is a significant reduction in manufacturing and installation costs compared with current PV techniques.” Moreover, manufacturers could enjoy lower costs; this is because microcells require relatively little material to form well-controlled and highly efficient devices.
Additional benefit is the cells’ flexibility – they could be made from almost any wafer, because they are only hundreds of micrometers in diameter. Furthermore, if one cell proves defective in manufacture, the rest still can be harvested, while if a brick-sized unit goes bad, the entire wafer may be unusable. According to Okandan, the flexible substrates can also be easily fabricated, giving high-efficiency PV for ubiquitous solar power.
Although the team is already considering moving their development to the commercial stage, the possible applications are yet to be designed and manufactured.
TFOT has also covered the Bio-Based Solar Cells, developed by BioSolar, and the Roll-Up Solar Panels, which could be used on irregularly shaped objects such as automobile roofs. Other related TFOT stories include the CIGS Solar Cells, which provide low-cost solutions for harvesting solar power, and the Gratzel Cells, plastic-based cells that use nonvolatile electrolytes.
For more information about the revolutionary glitter-sized solar photovoltaics, see Sandia’s website.