Bandgap Engineering Increases Efficiency of Standard Solar Cells with Nanowire Technology

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Boston-area company Bandgap Engineering increases the average efficiency of standard, commercial solar cells by 0.4 percentage points, from 17.2% to 17.6%, just by replacing the standard surface texture with its nanowire technology.

Boston-area company Bandgap Engineering has increased the average efficiency of standard, commercial solar cells by 0.4 percentage points, from 17.2% to 17.6%, just by replacing the standard surface texture with its nanowire technology.

To demonstrate the increased efficiency, the company ran multicrystalline wafers through their standard industrial cell process. The only difference was that half the wafers in the batch had Bandgap’s patented, proprietary nanotexture, while other wafers had standard acidic texture.

“The best nanowire solar cell had 17.76% efficiency, compared to 17.32% for the best standard solar cell. Since the cell process was optimized for the standard cells, and not for nanowire cells, and since we have a clear path to further improve our technology, I expect further efficiency improvements with a fairly straightforward optimization,” said Jeff Miller, Bandgap’s Senior Device Scientist.

Bandgap has achieved larger efficiency improvements, but the significance of this result is that in previous experiments the full cell process was optimized for nanowire cells. This time, the cell process was identical to the regular process, except for a single step — the texturing step. 

“This result demonstrates an efficiency benefit of nanowire solar cells over conventionally textured solar cells and demonstrates how simple and powerful an upgrade we can provide to commercial cell makers,” commented Bandgap president Marcie Black. 

The firm also announced a new efficiency record of 19% for a monocrystalline nanowire solar cell made in collaboration with the Georgia Institute of Technology.

According to the company, its nanowire technology is a drop-in upgrade for today’s crystalline silicon manufacturers using standard processing technologies. As the technology gives low reflection for all grain orientations, it is an ideal upgrade for multicrystalline wafers, which have higher reflection. Additionally it can enable some more advanced high-efficiency and lower-cost processes, which are already on many manufacturer’s roadmaps.