Solar Cell
What Is a Solar Cell?
A solar cell — Turkish güneş pili — is a semiconductor device that converts sunlight directly into electrical power via the photovoltaic effect. Solar cells are arranged into panels and arrays to provide useful power for satellites, UAVs and ground systems.
Crystalline silicon dominates terrestrial applications; multi-junction gallium-arsenide (GaAs) cells provide higher efficiency for space and HALE-UAV applications.
How Does a Solar Cell Work?
Photons absorbed in the cell create electron-hole pairs in a p-n junction; the built-in electric field separates the charges, producing a voltage and, when connected to a load, a current. Multi-junction cells stack several materials tuned to different parts of the solar spectrum, achieving efficiencies above 30 %.
Antireflection coatings, surface texturing and high-purity silicon raise terrestrial cell efficiencies into the 20 % range.
Where Are They Used in Defense?
- Satellite power arrays
- High-altitude long-endurance (HALE) and solar-electric UAVs
- Remote sensor stations and unattended ground sensors
- Forward-base power augmentation
- Field-portable soldier-power kits
Key Features
- Efficiency from ~20 % (Si) to ~33 % (multi-junction GaAs)
- Long service life (15-25 years for Si)
- Silent, emission-free generation
- Modular sizing
Solar Cells in Türkiye
Turkish companies — TUSAŞ Space Systems, TÜBİTAK UZAY and several private firms — develop satellite solar arrays for indigenous spacecraft (GÖKTÜRK, İMECE, Türksat 6A).
Domestic terrestrial PV manufacturing has also grown rapidly under broader energy-policy goals, supporting some defense and infrastructure applications.
Quick Facts
- Category: Photovoltaic device
- Principle: Photovoltaic effect in p-n junction
- Typical efficiencies: ≈ 20 % (Si), ≈ 33 % (multi-junction GaAs)
- Defense uses: Satellites, UAVs, remote sensors
- Turkish stakeholders: TUSAŞ, TÜBİTAK UZAY, private firms
Frequently Asked Questions
Why use multi-junction cells in space?
Because mass and area are limited; higher efficiency means more power per kilogram and per square meter.
Can UAVs fly on solar power alone?
HALE-class solar-electric UAVs can stay aloft for weeks if their daytime solar power exceeds nighttime battery draw.
Are solar cells useful in tactical military applications?
Yes — for unattended ground sensors and remote stations they reduce battery resupply burden.
Does Türkiye produce solar cells for satellites?
Yes — domestic capability in satellite solar arrays has matured alongside Türkiye’s indigenous satellite programs.
