Researchers in China have made progress toward a new, cheaper approach to producing solar panels, according to BBC News. While solar panels conventionally rely on pricier, yet efficient, silicon, the new approach uses carbon and plastic to create more affordable organic photovoltaics – which the new study has shown could be equally efficient as silicon.
In addition to their lower cost, organic photovoltaics can be dissolved in ink and printed on materials such as plastic, which can in turn be included in clothing, or affixed to the surface of structures, even without a flat surface.
Until now, relatively lackluster efficiency was holding back the use of these organic photovoltaics, which had achieved about half of the recently set world record of 27 percent for silicon cells. This refers to the percentage of sunlight that solar cells are able to convert into electricity.
Only this past April, researchers managed to achieve 15 percent efficiency from organic solar cells. Now the authors of the new study say there is a clear path to 25 percent efficiency.
Estimates have shown that solar cells with 15 percent efficiency could offer electricity at less than 7 cents per kilowatt-hour, over a 20-year lifetime. Considering that the average electricity cost in the US last year was 10.5 cents per kilowatt-hour, and that the new study suggests that even higher efficiency is possible, this could represent a serious breakthrough towards practical solar energy.
Typically, organic photovoltaics are less efficient because of the looser bonds of the organic molecules, which can slow the movement of electrons. To address this problem, the researchers used a tandem cell approach, with two layers.
According to Dr. Yongsheng Chen, of Nankai University in Tianjin:
“We have two layers of active materials, each layer can absorb different wavelengths of light. That means you can use sunlight in the wider wavelengths or more efficiently and this can generate more current.”
Chen points out that the parallels between organic photovoltaics and organic light-emitting diodes (OLED) technology, increasingly used in higher-end TVs in recent years.
“The physical principle is the same, just a different direction, one is from solar to electricity, the other from electricity to light, the device and structure are similar. I am very positive for OPV, and it may not need five years,” according to Chen.
The cells could work indoors, and even be semi-transparent, and incorporated into windows. They are lightweight, with the potential to be used on buildings in the developing world that might not support heavier solar panels. The potential applications are extensive, and along with the cost, the technology could prove a considerable boost to the use of solar power in general.