Australian engineers at the University of New South Wales have pushed sunlight-to-electricity conversion efficiency to 34.5% – establishing a new world record for unfocused sunlight and nudging closer to the theoretical limits for such a device.
The record was set by Dr Mark Keevers and Professor Martin Green, Senior Research Fellow and Director, respectively, of UNSW’s Australian Centre for Advanced Photovoltaics, using a technology that splits the incoming rays into four bands to squeeze even more electricity from each beam of sunlight.
“What’s remarkable is that this level of efficiency had not been expected for many years,” said Green, a pioneer who has led the field for much of his 40 years at UNSW. “A recent study by Germany’s Agora Energiewende think tank set an aggressive target of 35% efficiency by 2050 for a module that uses un-concentrated sunlight, such as the standard ones on family homes.
More details of the UNSW research can be found at: http://newsroom.unsw.edu.au/news/science-tech/milestone-solar-cell-efficiency-unsw-engineers
Hot on the heels of the UNSW announcement, researchers at MIT demonstrated for the first time, a device based on a method that enables solar cells to break through a theoretically predicted ceiling on how much sunlight they can convert into electricity. Ever since 1961, it has been known that there is an absolute theoretical limit, called the Shockley-Queisser Limit, to how efficient traditional solar cells can be in their energy conversion. But there are some possible avenues to increase that overall efficiency, and one of them using devices known as solar thermophotovoltaics, or STPVs, has been used by the MIT team.
The basic principle is simple: Instead of dissipating unusable solar energy as heat in the solar cell, all of the energy and heat is first absorbed by an intermediate component, to temperatures that would allow that component to emit thermal radiation. By tuning the materials and configuration of these added layers, it’s possible to emit that radiation in the form of just the right wavelengths of light for the solar cell to capture. This improves the efficiency and reduces the heat generated in the solar cell.
According to the author of the research, the technology could more than double the theoretical limit of efficiency, potentially making it possible to deliver twice as much power from a given area of panels.
More details of the MIT research can be found at: http://news.mit.edu/2016/hot-new-solar-cell-0523