Earth has been gifted huge amounts of energy from the Sun. That makes 885 million terawatt hours every year. Humans have always taken some help from the Sun’s massive energy enrichment. Now may it be directly or indirectly. For instance, to dry clothes or grow plants.
However, there remains another sort of usage of this abundant energy. That is solar cells which subsequently allow us to directly turn sun’s energy into electricity. Many laboratories have been working tirelessly to determine the technology that allows us to harness the free and reliable clean energy from the sun.
It has been evident for years that that light can have a direct effect on the electrical properties of some materials. This is further known as the photoelectric effect. Similarly, Albert Einstein received a Nobel Prize in 1921 whilst explaining this theory. Photovoltaic (photo = light, voltaic = electric formed through chemical reactions) is based on a simple dilemma known as the photocopy effect. They allow us to convert light directly into electricity.
The main component of all contemporary electronics is silicon. And most photovoltaic cells comprise of silicon. Silicon is regarded as a special material because it combines a unique arrangement of electrons. It has four out of eight electrons in its outer shell. This subsequently depicts that it induces perfect covalent bonds with other four atoms and hence forming a lattice structure.
So now the question remains, out of all the elements in the periodic table, why use silicon as the heart? Silicon is basically most common element for a photovoltaic effect because of the maximum wavelength energy it absorbs. The number is around 800 nanometres and it is close to radiation produced by the sun. The sun emits a radiation ranging between 200 to 2,000 nanometres. However, the common majority range is always expected to be within 420 to 700 nanometres.
On The Brink Of Efficiency
It must be mentioned that no method or theory is 100% efficient for energy transformation. For example, plants carry out the process of converting sunlight into energy with an efficiency rate of either 5 or 6 percent. Similarly, a fossil fuel power plant is only capable to produce an efficiency scale of 30-50 percent.
This subsequently means that there are some issues as to why solar cells are not entirely efficient in converting sunlight into electrical energy. Firstly, this might be due to the insufficient photons that would restrict the electrons to sway free from their electron hole pairs. Secondly, sometimes photons provide exceeded energy that is over the required numerical for the electrons to break free from their electron hole pairs.
The maximum efficiency rate of a silicon photovoltaic cell in converting sunlight into electrical energy is around 20 percent. Although the research is being laid out for cheaper cells without wasting numerous amounts of energy.
Solar energy has such a bright future in the upcoming times that we might as well estimate it as limitless. Fortunately, its also renewable unlike fossil fuels which are running out of time as we use them. Additionally, solar energy doesn’t cause pollution at all or any sort of other damage to Earth’s surface.
Although the main issue remains, what to do when the sun doesn’t shine. We use a considerable amount of energy whenever the sun is shining outside. For example, air conditioners in the summertime. But we still need a storage programme to store energy when the clouds conceal the sun’s true beauty.