It is the human endeavor to improve upon everything we encounter including solar cells, in a bid to better our lives and living. Ever since the growing concern of environment pollution and global warming has reached alarming levels, so has the effort to develop even better and more efficient renewable energy devices. Hot Solar Cells is one recent development that seeks to make a significant step in the race to clean energy.
The solar panels atop the roof are increasing becoming a reality, a commonality these days. Starting from the 60’s, we have come a long way into how much electricity a solar cell can produce. A normal solar cell has a theoretical maximum efficiency of 33.16% with real efficiency at a maximum of around 20% in test conditions.
Naturally, scientists try to beat this limit, and they look for avenues where this breakout can happen. One way is to use multiple layers of solar cells, that is widely considered and shown some results with increased costs of course. The second way is to converting the sunlight heat before generating electricity using solar thermophotovoltaics or STPVs.
Scientists at MIT conducted a demonstration where they effectively increased the power output of a low efficiency normal solar cell using thermophotovoltaic device between it and the light source. The thermophotovoltaic device in this demonstration composes absorber-emitter which converts lights into heat and a nanophotonic crystal which converts heat back into a light of the desired wavelength which solar cell needs.
This process converts maximum possible energy into light wavelengths required by solar cell thus increasing efficiency levels of the cell. In practice, the absorber material used was an array of carbon nanotubes for all wavelength absorption for maximum heat generation for nanophotonic crystal, which upon getting heated would release the desired light wavelength. The demonstration has been a success, with further steps that need to be taken is planning of taking this into commercial viability.
Despite the great outcome of getting much more power from the same given area of solar cell, another fact was the use of a low-efficiency solar cell, which upon replacement with a more efficient solar cell would allow a further increase of power output. At this point, it’s best to hope this principle soon gets more momentum into getting commercially produced and we gain benefit sooner.