Work at Japan’s National Institute of Materials Science may allow solar cells to be built into you house and car windows, windshield and even your sunglasses. The NIMS group, led by Dr. Shojiro Komatsu, has been interested in BN cell because it would be transparent to the visible light spectrum. Researchers claims to have already developed the world’s first BN prototype. They use a proprietary process to produce a BN/Si heterojunction diode. They report that their prototype has a generating efficiency of about 2%. Obviously, this is still a small level of efficiency, but researchers respond:

“There is still a large gap between this and the level (18%) of today’s most advanced silicon solar cells. However, as data obtained with the world’s first prototype of a BN/Si heterodiode solar cell, it is considered a promising value for the future.”

The group also uses micron-sized cones to cover the surface the cell to improve the light absorption efficiency by cutting down the amount of reflected light.