MIT researchers have put a new spin on harvesting solar energy by developing a solar cell that absorbs heat from the sun far more efficiently than current models. A research paper published in Nature Nanotechnology describes the process as augmenting the conventional silicon-based solar cells with a second layer of nanotubes and photon-absorbing crystals.
In layman’s terms, silicon is used in conventional solar cells because it interacts with a wide range of light wavelengths, allowing it to absorb energy from all of them. While it is the single best material for the job, there are plenty of wavelengths that it can’t reach. The new nanotube layer is there as a catch-all to gather the rest, causing it to generate energy in the form of heat that is then stored for conventional use. A primary benefit of converting energy to heat is that heat is easier to store, meaning that power generated from these cells would have the added benefit of longer storage time.
Previous tests into integrating thermal energy with solar cells have proven only marginally successful, producing devices with a maximum efficiency of 1%. The new cell clocks in at an efficiency of 3.2%, and the research team hopes that with further work they can reach as high as 20%. Improvements will be focused on growing the chip from the current 1-cm model to a 10-cm model. Heat dispersion is expected to be the primary challenge, as heat bleeds out increasingly rapidly as an object increases in size leading to wasted energy .
The research has experts in solar energy excited. ““This work is a breakthrough in solar thermophotovoltaics, which in principle may achieve higher efficiency than conventional solar cells because STPV can take advantage of the whole solar spectrum. … This achievement paves the way for rapidly boosting the STPV efficiency.” said Zhoumin Zhang, a professor at the Georgia Insitute of Technology. Any advancement in solar technology is a win for the environment, and this is one of the biggest splashes that has happened in a while. The question on my mind is does it have what it takes to go commercial? Let me know what you think.