Advanced Topic 718 of 1102 Inorganic Chemistry
Photovoltaic Materials
Semiconductors such as silicon convert sunlight to electricity.
In-depth explanation of Photovoltaic Materials
Photovoltaic materials are semiconductors that convert sunlight directly into electricity. A photon with energy above the band gap excites an electron across the gap and leaves behind a hole. A built-in field, usually from a p-n junction, separates the electron and hole so that they flow to external contacts. Silicon, with a band gap of about 1.1 eV, dominates the market because it is abundant, though its indirect gap makes it a weak absorber. The Shockley-Queisser limit gives a theoretical maximum efficiency of about 33 percent for a single-junction cell.
Going deeper: Photovoltaic Materials
Key ideas: Solar cells use p-n junctions in which absorbed photons with energy above the band gap create electron-hole pairs, separated by the built-in field. Si band gap is 1.12 eV (indirect), GaAs 1.43 eV (direct, strongly absorbing), CdTe 1.5 eV, and perovskites 1.5 to 1.6 eV. Shockley-Queisser limit is near 33 percent for a single junction; commercial Si modules reach 20 to 24 percent. Tandem cells stack different band gaps. Wavelength for gap: lambda in nm equals 1240 divided by E in eV.
Common mistakes and connections: Students think larger gap is always better; it raises voltage but reduces absorbed photons, giving an optimum near 1.3 to 1.4 eV. Photon energy above the gap is lost as heat. Cells output DC. Doping: phosphorus gives n-type, boron p-type. Links to semiconductors, band theory, perovskites and quantum dots.
Visualization of Photovoltaic Materials
Photoelectric picture of a silicon solar cell: photons above the band gap of about 1.1 eV free electrons and generate current. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Commercial silicon solar panels typically achieve efficiencies of about 20 to 23 percent.
Frequently asked questions about Photovoltaic Materials
What is Photovoltaic Materials?
Semiconductors such as silicon convert sunlight to electricity.
Is Photovoltaic Materials a beginner, intermediate or advanced topic?
Photovoltaic Materials is a advanced topic in Inorganic Chemistry. It builds on beginner and intermediate topics, so review those first if needed.
What should I learn before Photovoltaic Materials?
Study these earlier topics in Inorganic Chemistry first: Metal-Organic Frameworks, Nanomaterials, Quantum Dots.
What comes after Photovoltaic Materials?
The next topics in Inorganic Chemistry are Water Treatment and Inorganic Nomenclature.
Can I practise Photovoltaic Materials with quizzes?
Yes. The interactive lesson includes a self-check question on Photovoltaic Materials, and the Inorganic Chemistry quiz draws on every topic in this area.
Where Photovoltaic Materials fits in Inorganic Chemistry
Photovoltaic Materials is topic 103 of 113 in Inorganic Chemistry.