Beauty in Black
This article was first featured as a LinkedIn post from Canadian Solar CEO Dr. Shawn Qu:
Color discrimination is unacceptable in our civilized world as we truly believe that all human beings are created equal, white, black, yellow or whatsoever. When it comes to silicon solar cells and panels, however, black is better than the grayish blue which still is the mainstream color these days. Blackness implies that the solar cell surface absorbs most of the visible sunlight. The more light the solar cell absorbs rather than reflects, the more light can be converted into electricity, resulting in a higher energy conversion efficiency and electricity output.
After over four years of research and development, we have started to mass-produce our black silicon solar cells. We call it Onyx Technology. We use a proprietary wet process technology to generate nanometer-scaled structures on the sunny side of the solar cell. One nanometer equals to 1.0E-9 meter, or 1/1,000,000,000th of a meter. The scale of such nanometer structures is in the same range as the blue light wavelength in the Sun’s spectrum, creating ”multiple internal reflections” which help trap such light rather than let it scatter out. As a result, the solar cell and panel appear black, offering pleasing aesthetics compared to traditional solar cells and panels. More importantly, by trapping the light more efficiently, we can improve the absolute cell efficiency by 0.5% (or 3% relative). This translates to an almost 9 Watt higher power for our 72-cell solar module at an equal or lower cost!
And cost is important for solar, as many investors still compare solar with fossil fuels on a pure cost basis, without considering the environmental benefits solar provides. It is not a fair apples-to-apples comparison, but I have to live with it. I simply asked our tech team to develop our next generation of solar products with higher wattage and ever lower cost. Of course quality and reliability always come first for Canadian Solar, as demonstrated by our product bankability and top rankings under PVUSA Test Conditions (PTC). While there is a full line of technologies that may have higher efficiency to convert sunlight into electricity, few can do it at the same cost as the mainstream multi- or mono-crystalline silicon solar panels. Calling it a ”game-changer” may sound too flashy, but Canadian Solar’s black silicon Onyx Technology is a giant leap forward for multi-crystalline cell technology. It will become a future baseline in our production, and it fulfilled my simple yet challenging requirement: higher wattage, lower cost.
In 2015 the worldwide accumulated solar installations surpassed the 200 GW landmark. We have also nickel-and-dimed our way to reduce the costs for solar panels to one-fourth of what it was only five years ago. Nowadays we are really “penny pinchers”: We evaluate the processing costs of our solar panels to the scale of one-hundredth of a cent per Watt – call it our “nano-technology” for manufacturing cost control.