How solar cell is made

2025-05-07

The manufacturing process of solar cells is the major factor in determining conversion efficiency, costs and competitiveness of the market as a renewable energy source. Bonada will describe the manufacturing methods of solar cells in detail in order to facilitate an understanding of the production process of this green energy technology.

1. Major manufacturing technologies of solar cells

The major solar cell manufacturing technologies currently on the market are as follows.

- Crystalline silicon solar cells (monocrystalline silicon, polycrystalline silicon)
- Thin-film solar cells (amorphous silicon, cadmium telluride, copper indium gallium selenide)
- New solar cells (perovskite, organic photovoltaics, etc.)

Crystalline silicon cells comprise more than 90% of the global market share and have been widely accepted globally largely due to mature technology and more stable efficiency.

2. Making Process of Crystalline Silicon Solar Cells

1. Purification of silicon material

Silicon material purity is the main material of solar cells: high-purity silicon is commercial grade silicon which has been purified to > 99.9999% (solar grade silicon) either by modified Siemens method or fluidised bed method.

2. Silicon ingot/wafer preparation

Single crystal silicon (mono-Si): Single crystal silicon rods are grown using the CZ method, which are then sawed into silicon wafers.
Polycrystalline silicon (poly-Si): Polycrystalline silicon blocks are developed using the ingot casting method, which are then sawed by wire saw.

3. Cell manufacturing

Cleaning and texturing: Chemical etching is mentioned to passivate and create a "velvet" structure on a micron-level to reduce light reflection.
Diffusion junction: Phosphorus or boron doped in a high-temperature furnace to create the junction for a P-N junction
Anti-reflection film coating: Such as deposition of silicon nitride thin films which can help with the light absorption.
Electrodes screen printing: Silver, or aluminum paste screen printed onto wafers to create the negative and positive electrodes.

4. Packaging (modules)

After connecting all the cells, the module is encapsulated with EVA, tempered glass and backplane so it becomes a weather resistant solar module.

3. Manufacturing characteristics of thin-film solar cells

The manufacturing aspects of thin-film cells are much simpler than crystalline solar cells, and typically they use deposition either by vapor deposition (such as PECVD), or by sputtering coating techniques to deposit an active layer directly on glass or flexible substrates. Thin-film cells can be made to handle "roll-to-roll" manufacturing technologies and are largely mass produced but their efficiencies are generally not as high as crystalline solar cells.

Solar cell cost price per watt

Solar cell pros and cons