4.1 Generations of solar cells
Crystalline silicon solar PV is the technology of choice in today’s commercial solar PV electricity generation
It is undoubted that solar photovoltaic is the most likely-looking green energy technology in the 21st century and is the best technology to exploit largely untouched idle energy source: Solar energy. It is having great potential for cutting fossil fuel consumption and harmful emissions. And it is armed with all the necessary tools and implements needed to reverse the fast-maturing change in the climate system. But… However, it is unfortunate that we have not yet been using it adequately.
To illustrate, take a look at the Following pie chart. It displays the world’s electricity generation in 2015, by energy sources.
Figure 01: World electricity generation by source in 2015 
The cumulative electricity generation in 2015 was 24 310 TWh. As illustrated by the chart, coal, gas and oil have generated 40.2%, 21.3%, and 4.3% of the electricity demand, respectively while solar PVs generated merely 2%. In a nutshell, almost 65.8% of electricity demand has been met by burning fossil fuels. It is 30 times greater than the solar electricity generation. What does it imply?
Assuming no change in the electricity demand, we need to double the solar electricity generation each year if we want to completely replace fossil fuels with solar electricity within five years (25= 32). Sound interesting!
But… Keep in mind!
Demand for electricity will never remain unchanged or will never be decreasing. It will be constantly increasing. Obviously!
So… As we can see it, we have a lot to do if we really want to make the Prussian blue, orange and yellow colored segments dark-blue colored! Of cause, wind and other renewable energy sources can also play a big role. But still… as the big brother in the renewable energy industry with the greatest energy potential, solar PV technology must shoulder the key responsibility.
In order to cut fossil fuel consumption…
In order to reverse the greenhouse effect…
In order to fight against the climate change…actively, convincingly with enthusiasm…
We need to spread out solar PVs over the rooftops, across the regions, territories and the world. This requires manufacturing more and more solar PVs and thus needs a copious amount of raw materials. Simply, the raw materials need to be abundant in nature!
Silicon which is the key raw material in commercialized crystalline photovoltaic industry is such material available in the form of silicon dioxide in sand and quartz. And it is one of the most abundant elements in the Earth’s crust (29.5%) as we discussed earlier .
Silicon offers many other benefits over other semiconducting materials. Hazardous materials coming with electronic devices, pesticides, fossil fuels and, etc. causes a range of detrimental environmental effects and health problems whilst our planet has terribly been contaminated with a lot of toxic materials. Therefore, we should take every possible step to prevent the already stressed-earth from contaminating. Unlike many other photovoltaic materials, silicon is a non-toxic material which does not impose any known adverse effect on the environment or health. This property makes it an ideal material for mass production of solar PVs.
 Breyer, C., Bogdanov, D., Aghahosseini, A., Gulagi, A., Child, M., Oyewo, A. S. & Vainikka, P. (2017). Solar photovoltaics demand for the global energy transition in the power sector. Progress in Photovoltaics: Research and Applications.
 Yaroshevsky, A. A. (2006). Abundances of chemical elements in the Earth’s crust. Geochemistry International, 44 (1), 48-55.