A new design for thin-film solar cells that requires significantly less silicon and may boost the efficiency is the result of an industry/academia collaboration between Oerlikon Solar in Switzerland and the Institute of Physics’ photovoltaic group at the Academy of Sciences of the Czech Republic.
Amorphous silicon solar cells and microcrystalline silicon tandem cells (Micromorph) provide a long-term option for low-cost, high-yield industrial production of solar panels. They can provide an energy payback within a year. However, the stable panel efficiency of these cells is less than the efficiency of currently dominant crystalline wafer-based silicon, said Milan Vanecek, who heads the photovoltaic group at the Institute of Physics in Prague.
According to Vanecek, the amorphous and micromorph cells are required to be very thin because of the tight spacing of the contacts in the design of the cell. The collaborative group’s goal was to take these less-expensive cells and solve the stable panel efficiency problem.
The team’s new design focuses on thicker cells that are better at absorbing sunlight, but the distance between the electrodes remains very tight.
Current liquid crystal display (LCD) designs inspired the group, as they make use of a technology already used in LCDs. The result is a “Swiss cheese” or honeycomb array of micro-holes etched into one of the layers of the cells.
“The potential of these efficiencies is estimated within the range of present multicrystalline wafer solar cells, which dominate solar cell industrial production,” Vanecek said. “And the significantly lower cost of Micromorph panels, with the same panel efficiency as multicrystalline silicon panels (12 to 16 percent), could boost its industrial-scale production.”
According to the group, the design can be further optimized to continue improving efficiency. The extent to which efficiency can be optimized using this method is not known, but it could possibly help solar power become more feasible in the future.