The future of solar power
flows through the circuit back into the solar cell, now entering one of the holes in the Silicon p-side, so nothing is used up or worn out. As such, electrons act as the only moving part of a solar cell.
As it stands right now, solar panels have an approximate efficiency of 15-20% in converting sunlight into energy that can be used in homes. Whilst this may not seem like much, it is far more than the approximate 0.3% efficiency of the sunlight used to grow plants and burn them (i.e. biomass). The theoretical limit for a single-junction cell would be around 33%, as going higher than this would require the layering of solar cells. By layering solar cells, different elements with varying work functions can capture the low, medium, and high-energy photons, resulting in efficiency that is in the 40-50% range. However, in order for the panel to work, the crystallographic lattice (which is also present in silicon cells) has to run through the entirety of the cell, and for that to happen the materials must be grown very slowly so that the lattices align – this being a very expensive process (costing around $40,000 per square metre). Through higher levels of research and development, more and more different compounds have been tested in solar cells, with two of these standing out in particular.When using a hybrid organic-inorganic lead or tin halide-based materials, it allows for high efficiency combined with low cost. These are both known as perovskite-structured compounds, which are named after a type of mineral found in the Ural Mountains. Because perovskites have a layer-based structure, they have a broad absorption range, are cheaper to produce, and absorb more light than silicon, allowing for thin and even flexible solar cells/panels. Furthermore, perovskite-based solar panels have a high absorption coefficient, which means that the rate of decrease of intensity as it passes through the material is high, resulting in better absorption of sunlight. All of this means that you end up with a cheap, flexible, and more efficient solar panel than normal silicon PV cells. This has proved to work very well, with the highest ever recorded single-junction efficiency currently standing at 27.3% (using a 1cm^2 solar cell), accomplished by a tandem silicon-perovskite cell.
With such advances in this technology occurring, it is easy to see how this technology could be seen as what will power the future. And in fact, this technology has already evolved to the point where it is seeing a huge increase in use around the world. The increase in installation of solar cells has exceeded even Greenpeace’s expectations, as shown in figure 2. Furthermore, in areas with a high concentration of solar radiation, such as Saudi Arabia or the United Arab Emirates, the technology can allow for electricity to be cheaper than when using other sources. In the UAE, the Mohammed bin RashidAl Maktoum Solar Park covers 77 square kilometres, situated around 50 kilometres south of the city of Dubai. Whilst the global average
for producing electricity fromcoal stands at around £0.037 per kilowatt- hour (this is equal to one kilowatt of power sustained for one hour), the cost per kilowatt-hour that the owners of the solar park are pledging to sell for stands at around £0.02 – this being around 46% cheaper than the price of coal. Figure 2
However, despite all of its advantages, there are still drawbacks to using solar energy. The first being that. owing to perovskites and similar innovative technologies only being recent, solar cells are still
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