Photovoltaic (PV) cells, commonly called solar cells, are the components of solar panels that convert sunlight directly into electricity. Understanding the structure of PV cells is essential to understanding how solar energy systems can harness renewable energy.

1. Basic Structure

A typical photovoltaic cell consists of multiple layers of materials, each of which performs a specific function, namely capturing sunlight and converting it into electricity. The main components include:

Semiconductor material: usually silicon, which can be single crystal, polycrystalline or amorphous.

Anti-reflective coating: used to reduce the reflection of sunlight and ensure maximum absorption.

Metal contacts: located on the front and back of the cell, used to collect and conduct the generated electricity.

2. Semiconductor layer

PV cells are usually composed of two types of semiconductor layers that form a pn junction:

P-type layer: The p-type layer is doped with materials such as boron, which produces a large number of positive charge carriers (holes).

N-type layer: The n-type layer is doped with elements such as phosphorus, which can provide additional electrons, thereby producing negative charge carriers.

3. Anti-reflective coating

Anti-reflective coating is applied to the surface of the cell to minimize the loss of sunlight due to reflection. This coating ensures that more sunlight penetrates the cell, which helps to generate electricity.

4. Metal contacts

Front contact: A grid-like structure made of fine metal wires is placed on the surface of the cell. This allows sunlight to pass through and collect the electrons produced.

Back Contact: A solid metal layer covers the entire back side and acts as a second electrical contact.