[Editor's note: This is the first in a monthly roundup of the leading edge of solar innovation and breakthroughs in solar technology. We present these selected findings -- which come from the halls of academia and the R&D labs of research companies -- as a look at what's possible for the future of solar, although these innovations may never actually reach the marketplace.]
Fixing wafer defects with hydrogen atoms
Developer: NewSouth Innovations Pty Ltd., a subsidiary of Australia’s University of New South Wales
How it works: NewSouth Innovations’ patent published at the end of 2013 describes “a new method of hydrogenation for silicon solar cells.” During the manufacturing process, hydrogen atoms are controlled to fix defects in crystalline silicon wafers before being processed into cells and modules.
What it promises: The innovators expect to enable the production of high-efficiency crystalline silicon cells and modules with lower-quality, lower-cost silicon wafers. Using their technique, today’s crystalline silicon solar panels converting only around 17 to 18 percent of incoming sunlight into electricity could reach into the low 20s.
“Our patented advanced hydrogenation technology will allow lower-quality silicon to outperform solar cells made from better quality materials, producing higher efficiencies at significantly lower cost,” said the lead scientist on the team, UNSW’s Stuart Wenham, upon receiving a prize for the invention in January.
Commercial arrival: Wenham — who also is the CTO of Suntech Power — and his team are working with six large solar manufacturers to bring the innovation to market. It’s not clear yet exactly when commercialization will occur. NewSouth Innovations recent research agreement signed with solar cell and module maker China Sunergy calls for five years of research collaboration. So it could take at least that long.
But given the fact that the overwhelming majority of solar panels in the market today are made of crystalline silicon, and the fact that the players named in the patent are veterans of high-volume manufacturing, this innovation appears to have an excellent shot to incrementally raise the sunlight conversion efficiency and lower the cost of the most common type of panel now available.
Harnessing heat to add efficiency
Developer: Massachusetts Institute of Technology
How it works: In a recent paper, researchers at MIT describe their efforts to develop an infrared-sensitive photovoltaic cell. They do this by adding semiconductor materials atop a conventional crystalline PV cell in order to access a broader spectrum of sunlight. MIT uses a two-layer materials mix that includes carbon nanotubes and photonic crystals to absorb more light energy, turn it into heat and harness that heat for electricity.
What it promises: Such “thermophotovoltaic” (TPV) approaches have been developed in the lab for decades, although MIT says its new design offers improvements that could finally lead to commercial markets. Ultimately, the goal of adding semiconductor layers to PV cells always has been to increase conversion efficiency beyond that of standard solar cells and panels, and lower cost. MIT expects to reach an efficiency of at least 20 percent.
Commercial arrival: Adding layers means adding steps to the manufacturing process. MIT will need to show that its efficiency gains can outweigh the increased cost of production. Otherwise, its infrared-sensitive PV cell will not make much of commercial impact.
Developer: North Carolina State University and the Chinese Academy of Sciences
How it works: Researchers at NC State and the Chinese Academy of Sciences in a recent paper in the journal Advanced Materials describe their collaboration to boost the efficiency of polymer-based solar cells by modifying the molecular structure of the polymer used in such cells. Their innovation is the creation of a polymer known as PBT-OP.
What it promises: Researches say their modification can boost the efficiency of such polymer-based solar cells by more than 30 percent. But that’s not saying much. Polymer-based PV cells are among the least efficient, with sunlight conversion efficiency in the mid-single digits.
Commercial arrival: It is unclear when, and if, polymer solar cells will make waves commercially. Konarka Technologies Inc., one of the most recent commercial ventures focused on polymer-based solar cells, was forced to liquidate after filing for bankruptcy in 2012. And a Nobel laureate led the effort.
Solar orb too good to be true?
Developer: Rawlemon Solar Devices
How it works: Start-up Rawlemon is seeking to raise $100,000 through a crowd-funding effort to launch a beta version of its spherical solar concentrator for mobile phone charging and lighting. Rawlemon’s conceptual solar devices concentrate sunlight up to thousands of times with a pedestal-mounted water-filled orb that tracks the sun both vertically and horizontally. Different than other concentrators, it is so powerful it can harvest diffuse light and even moonlight, the company claims.
What it promises: Rawlemon, led by German architect Andre Broessel, repeatedly uses the terms “revolution” and “revolutionary” in its crown-funding pitch.
“Free energy everywhere! Be part of the Solar Revolution!”
Free? Really? I don’t’ know about you, but my BS detector is freaking out.
The company claims it “can reach up to 70 percent yield surplus compared to a conventional PV panel.” Rawlemon also targets building-integrated applications with its aesthetically pleasing concentrating solar orb.
Indeed, it does look cool. It also looks too good to be true. And it probably is.
Commercial arrival: Very unlikely. The company, which says it has prototypes, has raised just $21,840 to date in its crowd-funding effort. Yet it is “close to entering production,” pending funds for “production tooling, large component order, global certifications.”