Coated Solar Cells Capture More Sunlight

Engineers at Rensselaer Polytechnic Institute have developed a coating that makes solar cells more efficient. The new coating lets solar cells absorb 96.2% of the sunlight shining on them. For comparison, untreated silicon solar cells absorb only 67.4%. Even better, the coating works across the entire spectrum of sunlight, from UV to infrared. The coating also absorbs sunlight evenly and equally from all angles. This means solar panels treated with the coating would absorb 96.2% of the sunlight hitting them, regardless of the sun’s position in the sky. Researchers say that coated cells would not need to rely on cumbersome pointing mechanisms to keep them facing the sun throughout the day, a technique now in wide use for industrial panels

The coating consists of seven layers, each 50 to 100-nm thick and made of nanorods of silicon dioxide and titanium dioxide positioned at oblique angles. The nanorods attach to a silicon substrate using chemical vapor deposition. Each of the layers bends the flow of sunlight to an angle that augments the coating’s antireflective properties. This means each layer transmits light and helps capture any light reflected from lower layers.