For many people “solar cells” conjures up images of dark, glassy modules mounted on rooftops. Generating electricity from sunlight, however, is becoming broader than a particular material, form factor or application.
Researchers are continually expanding photovoltaics’ reality. Four of the five news items in the current issue of ERN reflect this broadening. They’re about dye-sensitized, polymer, non-polymer organic inverted and nanotube-silicon heterojunction solar cells — four very different devices with different potential applications.
This diversity of photovoltaics research is driven by need, opportunity and the limitations of today’s sun-harvesting devices.
The needed transition to sustainable energy systems requires as many practical alternative energy sources as we can develop. There’s opportunity in recognizing that the vast amount of energy the sun radiates to the earth’s surface strikes wastelands, building façades, vehicles and portable electronic devices as well as rooftops. And existing photovoltaics’ limitations come down to the cost, bulk and brittleness of crystalline silicon.
Silicon is still king when it comes to converting sunlight to electricity efficiently, but the mere vision of an airplane’s skin or a cell phone’s plastic casing generating electricity is a good measure of how far we’ve come and our good fortune to be traveling down many roads at once.