One hurdle for scientists and researchers trying to improve solar cell efficiency has been the solar absorption rates. In other words, the amount of sunlight that the solar cell absorbs in relation to the amount of sunlight that hits the solar cell.

The problem that most experts focus on is a solar cell's ability to convert absorbed sunlight to electricity. Indeed this is the primary concern, as even the best-performing silicon solar cells (still the industry's strongest) reach conversion efficiencies around 25 percent. Yet even at the more realistic conversion rate of 15-20%, a solar cell that successfully absorbs more sunlight will obviously create more electricity. So absorption rates are not by any stretch of the imagination a negligible factor in solar cell production.

Thin-film solar cells, such as Cadmium Telluride (CdTe) cells among others, have long claimed high solar absorption rates, reaching levels of up to 90% and absorbing across the wide spectrum of solar radiation. The problem is that thin-film solar cells are historically inefficient relative to conventional silicon-based solar cells. So while these relatively high absorption rates -- and comparatively low manufacturing costs -- have enabled many thin-film manufacturers to compete within the industry, a corresponding low conversion efficiency has discouraged them from taking any sort of lead. Yet any discussion of solar absorption rates among different solar cells may soon be rendered moot.

A standard, uncoated silicon solar cell can absorb about 67% of the sunlight colliding with it, and that number depends largely on the angle of the sun in the sky. Nanotechnology, however, promises to change all that. Scientists at the Renssalaer Polytechnic Institute (RPI) have just announced the development of a nano-coating that boosts the solar absorption rate of a silicon PV cell from, at best, that 67% threshold to near perfect levels of more than 96%.

Their solution is made from nano-particles and is multi-layered and antireflective. The multi-layered makeup of the coating allows the solar panels to absorb a much wider range of sunlight, cutting down on reflection regardless of the sun's angle in the sky. The researchers claim that their nano-coating, which will continue to undergo testing, is compatible with nearly every solar cell material in existence, including thin-film and conventional PV technologies.