Intermediate Topic 1064 of 1102 Biochemistry, Environment & Industry

Solar Cells

Devices converting sunlight to electricity using semiconductors.

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In-depth explanation of Solar Cells

Solar cells convert sunlight into electricity using semiconductor p-n junctions. When photons with energy greater than the band gap are absorbed, they excite electrons from the valence band to the conduction band, creating electron-hole pairs. The built-in electric field at the junction separates these charges and drives them through an external circuit as current. Commercial silicon modules typically reach 20 to 23 percent efficiency, and perovskite-silicon tandem cells have exceeded 30 percent in laboratories. Dye-sensitised cells use molecular dyes on titanium dioxide to absorb light instead.

Going deeper: Solar Cells

Key ideas: A p-n junction in silicon: light with energy above the band gap (1.1 eV for Si) creates electron-hole pairs, the junction field separates them, giving current. Doping silicon with phosphorus gives n-type, with boron p-type. Commercial module efficiency about 20 to 23 percent; Shockley-Queisser limit about 33 percent for one junction. Perovskite and tandem cells exceed 30 percent in labs.

Common mistakes and connections: Mistake: thinking photons of any energy work equally; below the gap they pass through and above it excess energy is lost as heat. Output falls with temperature. Dye-sensitized cells mimic photosynthesis. Links to semiconductors, band theory and photoelectric effect.

Visualization of Solar Cells

A silicon cell absorbs photons with energy above its 1.12 eV band gap, lifting electrons from the valence to the conduction band to create current. The interactive lesson shows this as a live animation or chart.

Worked example and use case

A silicon cell, with a band gap of about 1.1 eV, absorbs visible and near-infrared sunlight.

Frequently asked questions about Solar Cells

What is Solar Cells?

Devices converting sunlight to electricity using semiconductors.

Is Solar Cells a beginner, intermediate or advanced topic?

Solar Cells is a intermediate topic in Biochemistry, Environment & Industry. It builds on the vocabulary of beginner topics in this area.

What should I learn before Solar Cells?

Study these earlier topics in Biochemistry, Environment & Industry first: Waste Management, Carbon Capture, Renewable Energy Chemistry.

What comes after Solar Cells?

The next topics in Biochemistry, Environment & Industry are Green Hydrogen and Nuclear Power.

Can I practise Solar Cells with quizzes?

Yes. The interactive lesson includes a self-check question on Solar Cells, and the Biochemistry, Environment & Industry quiz draws on every topic in this area.

Where Solar Cells fits in Biochemistry, Environment & Industry

Solar Cells is topic 89 of 127 in Biochemistry, Environment & Industry.