Solar Cell
Semiconductor device that converts sunlight directly into electrical current through the photoelectric effect.
Also known as: Photovoltaic Cell, PV Cell
What Is a Solar Cell?
A solar cell is the smallest component of a photovoltaic system. It is made of semiconductor material — usually silicon — and converts sunlight directly into electrical direct current. This process is based on the photoelectric effect.
Structure and Function
A crystalline silicon solar cell consists of two layers:
- n-doped layer (excess electrons)
- p-doped layer (electron deficit, so-called “holes”)
At the interface, an electric field is created (p-n junction). When photons strike the cell, electrons are released and driven in one direction by the electric field — current flows.
Cell Types and Efficiencies
| Cell Type | Efficiency (Module) | Feature |
|---|---|---|
| Monocrystalline | 20—23% | Highest efficiency, dark appearance |
| Polycrystalline | 16—18% | Cheaper, bluish appearance |
| PERC | 21—24% | Improved rear passivation |
| TOPCon | 22—25% | Tunnel oxide passivation |
| HJT | 22—25% | Heterojunction technology |
Practical Tip
A single solar cell delivers approximately 0.5—0.7 volts. Only by connecting many cells in series within a solar module are usable voltages achieved. Modern modules typically contain 60 to 144 half-cells.
Related Terms
Solar Module
Assembly of multiple solar cells in a weatherproof housing for generating electricity from sunlight.
Photoelectric Effect
Physical effect where light photons release electrons from a material -- the fundamental principle behind photovoltaics.
Semiconductor
Material with electrical conductivity between a conductor and an insulator -- the base material for solar cells, usually silicon.
Monocrystalline
Solar cell type made from single-crystal silicon with high efficiency and a characteristically dark, uniform surface.
Polycrystalline
Solar cell type made from multi-crystalline silicon with a bluish appearance and slightly lower efficiency than monocrystalline cells.
Efficiency
Ratio of usable electrical energy to incident solar energy -- indicates the effectiveness of a solar cell or system.