What Are Solar Cells Made Of?

1. Light absorbing material

It is a semiconductor material that is the main component of solar cells and is used to absorb sunlight. As mentioned - the most common material for solar cells is silicon, mainly because it is one of the most abundant minerals on Earth.

The absorbed light causes the generation of charge carriers, which then move to the contacts. To achieve high solar-to-electrical efficiency, some properties of this material should be considered: absorption, technical processing difficulty, price, and availability.

2. Sunlight Harvesting Layer

The purpose of these layers is to reduce light reflection from the front of the cell, or in other words, to increase transmission through the front of the solar cell and reduce light escaping from the cell when it is already inside:

A special layer called an anti-reflective coating (most commonly silicon nitride (SiN), which causes solar cells to appear bluish).

Surface textures (chemically etched or laser-assisted surface structures, similar to pyramids).

Usually these two ways are combined on the front. On the back of the cell, only the texture exists.

3. Charge separation (pn junction)

Solar cells have a built-in potential voltage, which is the force of electrons generated by sunlight to move to the contacts. This built-in potential is formed by a special type of junction called a pn junction. This type of junction is a fundamental part of today's electronics industry.

4. Charges (Contact)

As a power generation device, a solar cell needs to have contacts in order to transfer the charge to the terminal and accumulate or immediately use it with household appliances and the like. There are several contact structure variations in photovoltaics. Most silicon solar cells have what can be called a standard contact structure that everyone has seen. It changes a bit in time when further device optimizations happen, but it also looks similar.