Solar Panels - How they Work

With the ever growing concern of global warming, the world is looking out for some viable alternatives to solve the problems of electric power generation. Harnessing the energy of the Sun is a major research area today. Solar panels and solar cells have gained a significant importance nowadays. Though, there are issues regarding the cost-effectiveness of such panels, still they can play a major role in tapping solar energy. They are generally used in homes and commercial buildings to produce heat and electricity.

Working of Solar Panels
The basic chemical element that is involved in making solar panels is silicon. Silicon has atomic structure that makes it suitable for use in the construction of such panels. Let's consider the electronic configuration of silicon and see what are it unique features, that make it suitable for being used in solar cells. The electronic configuration of silicon is [Ne]3s²3p². As we can observe, a silicon atom has four electrons in its natural state. Ideally, the last orbit of the atom should have eight electrons to maintain its stable state. But silicon has just four electrons, so it needs four more electrons to gain stability and achieve a state of minimum energy and maximum stability. To gain four more electrons, a silicon atom combines with another silicon atom and shares four electrons. This is the reason for the strong bond that exists between two silicon atoms. However, since the octet is complete, the atom achieves a neutral state and hence it's deficit of positive and negative charges. To make it positively or negatively charged, boron and phosphorus are added to silicon. Boron charges the Silicon atom positively and Phosphorous charges it negatively. Why do we need to make it electrically charged? Well, two plates of neutral silicon won't conduct electricity and our effort is to generate electricity with the help of solar energy.

Phosphorus has an electric configuration as [Ne]3s²3p³. There is a deficiency of five electrons in its outermost orbit. The combination of silicon and phosphorus results in an eight electron atom accompanied by an extra electron. This extra electron imparts a negative charge to the entire combination. Moreover, Boron ([He]2s²p¹) is in need of three more electrons to complete its octet state. On chemically combining with silicon, boron-silicon plate has one deficit electron. This gives the plates a positive charge. Now, these two plates are combined together to form a conducting base for electricity.

Where and how is the solar power involved in this entire process? The heat and light energy from the Sun or more precisely the solar energy is believed to be made up of small energy packets called photons. These photons are the smallest quanta of the light energy that are transferred from the sun. When stated in a simple way, photons are nothing but the light energy. When photons strike the surface of solar panel plates that is negatively charged i.e phosphorus/silicon plate, they knock off an electron from the surface. This is the extra electron that was produced on combining silicon and phosphorus. The knocked off electron tries to escape from the vicinity of the plate. However, the boron/silicon plate is positively charged and is in need of electron. This lodged off electron is attracted toward the positive plate and this constitutes the electric current. Many conducive wires are joined to provide connection to the various plates. When solar panels are used on a large-scale, they are interconnected by wires to provide a path for the electric current to flow. More the number of electrons lodged off from the surface of the plates, more is the electricity produced.

Advantages of Solar Panels
They have only two major disadvantages; they can't operate during night and they are expensive. However, there are many advantages that are as follows

• Being a renewable energy source, we can rely on them for our future energy requirements.
• They are non-polluting.
• Solar energy requires no fuel, so it's a better alternative than oil energy.
• They are environmental friendly.
• They do not create noise pollution as they operate silently.

They are generally big in size, so that they can have large surface areas exposed to the sunlight. Nowadays, you can see solar panels installed on the roof tops and terrace of commercial buildings and homes. Though, they may not be the source of some large power generation, they can still contribute a lot in energy saving. Scientists are trying to eliminate the limitations of such panels and improve their productivity.