Washington (ISJ) - Researchers have developed a new kind of solar cell that can harnesses more sunlight. The new solar cell, according to researchers at MIT and Stanford University, combines two different layers of sunlight-absorbing material in order to harvest a broader range of the sun?s energy.
Researchers are hopeful the new development could lead to photovoltaic cells that are more efficient than those currently being used in solar-power installations.
The new cell uses a layer of silicon, a non-metal with semiconducting properties used in making electronic circuits, which forms the basis for most of today?s solar panels. However, it adds a semi-transparent layer of a material called perovskite, which can absorb higher-energy particles of light.
This is different from an earlier ?tandem? solar cell, in which the two layers were physically piled but each had its own separate electrical connections. But the new version has both layers connected together as a single device that needs only one control circuit.
The new version is much simpler to make and install. But it has its disadvantage also. The current produced is limited by the capacity of the lesser of the two layers. But the research team is currently working on to match the current output of the two layers as precisely as possible to optimize the output. �
The focus is now to increase the power efficiency, which is the percentage of sunlight?s energy that gets converted to electricity ? that is possible from the combined cell. In this initial version, the efficiency is 13.7 percent, but the researchers say they have identified low-cost ways of improving this to about 30 percent. Once it is achieved, there will be a substantial improvement over today?s commercial silicon-based solar cells. Researchers say this technology could ultimately achieve a power efficiency of more than 35 percent.
The next biggest challenges are to explore as to how to easily manufacture the new type of device and to make the material durable enough to be commercially viable.
Researchers say the exact formulation may not turn out to be the most advantageous for better solar cells, but is one of several avenues worth exploring. Associate professor of mechanical engineering Tonio Buonassisi, says: ?Our job at this point is to provide options to the world,? adding ?the market will select among them.?
Image courtesy: MIT