The Working Principle of Photovoltaic Solar Cells

Before talking about the mechanism of photovoltaic cells, we have to recall the working principle of the components of these cells to understand how the photovoltaic action occurs. The following explanation is very simplified because the aim of this article is educational and not research or academic.

First: Materials are generally divided into conductors, insulators, and semiconductors. With regard to conducting materials, such as copper, for example, the reason for this conductivity is due to the weak bonding of the electrons in the last orbit of these atoms, which facilitates their migration to their atoms, the floating of these electrons through the conductor, and the passage of electric current. On the contrary, the electrons of insulating materials such as wood, for example, are highly bound to their atoms, and therefore these electrons do not travel through the insulators, and therefore no electric current passes. In addition to these two types of materials, there are materials that do not conduct electric current well and are not considered a good insulator either. These materials such as silicon and germanium do not lose the electrons of the last orbit easily, but their electrons become easy to move when these materials are placed in certain conditions, such as raising their temperature or doping them, for example. These materials are called semiconductors.

Semiconductors can be used in pure or doped form. For example, pure silicon can be used after purifying its crystals, or silicon can be doped with additional materials such as boron, resulting in a P-type dopant semiconductor rich in positive holes, or silicon can be doped with materials such as phosphorus, resulting in an N-type dopant semiconductor rich in negative electrons.

The process of connecting a positive P-type semiconductor chip with a negative N-type semiconductor chip forms what is called a diode or a P-N junction. This link is the main component of the photovoltaic electricity generation system. You can delve deeper into understanding the principle of this link, but what we are currently interested in is knowing that this link does not allow electrons to pass from the negative N-type chip to the positive P-type chip except through an electrical circuit if you get enough energy to cross the insulating area between the two chips. That is, the electric current is generated and flows from the positive chip towards the negative chip.

PV cells, or photovoltaic cells, are devices that convert sunlight into electrical energy. They are made up of semiconductor materials, typically silicon, that absorb photons from the sun and release electrons, creating a flow of electricity.

PV cells are typically connected together to form a solar panel, and multiple solar panels can be connected to form a solar array. The electricity generated by a PV cell is direct current (DC) electricity, which is then converted into alternating current (AC) electricity by an inverter for use in homes and businesses.

PV cells work on the principle of the photovoltaic effect, which states that when light strikes a material, it can knock electrons into a higher state of energy, allowing them to flow as electrical current. In a PV cell, this process occurs in the semiconductor material, typically silicon.

When sunlight hits a PV cell, it is absorbed by the semiconductor material, which causes the electrons in the material to become excited and move around. These excited electrons are then collected by metal contacts on the surface of the PV cell, creating a flow of electricity.

The efficiency of a PV cell is determined by the amount of sunlight that is absorbed and converted into electrical energy. The efficiency of PV cells has been increasing over time, with the most advanced PV cells currently able to convert over 25% of the sunlight that hits them into electrical energy.

In summary, PV cells are devices that convert sunlight into electrical energy through the process of the photovoltaic effect. They are made up of semiconductor materials, typically silicon, and are connected together to form solar panels and arrays. The efficiency of PV cells has been increasing over time, making them a more viable source of renewable energy.

Photovoltaic cell Components

A photovoltaic cell or photocell is a device that converts light energy into electrical energy. It is made up of several key components:

1. Semiconductor material: The heart of the photocell is the semiconductor material, typically silicon, which absorbs photons from the sun and releases electrons, creating a flow of electricity.

2. P-N Junction: The semiconductor material is divided into two regions, the P-type and N-type, which creates a junction where the flow of electrons takes place.

3. Metal Contacts: The metal contacts are placed on the surface of the photocell to collect the excited electrons and create a flow of electricity.

4. Anti-Reflection Coating: An anti-reflection coating is applied to the surface of the photocell to minimize the amount of light that is reflected, thus increasing the amount of light that is absorbed by the semiconductor material.

5. Encapsulation: The photocell is encapsulated in a protective material, typically glass or plastic, to protect it from the environment and to increase its durability.

6. Bypass diodes: They are added to prevent any damage to the cell during high-light intensity or shading.

7. Junction Box: It contains electrical connections and other electrical components such as diodes, allowing the DC output of the cells to be connected to the inverter or other electrical equipment.

These components work together to convert light energy into electrical energy through the process of the photovoltaic effect. The efficiency of a photocell is determined by the amount of sunlight that is absorbed and converted into electrical energy.