Solar Energy

Learn the physics of energy harvesting from our most renewable source, the Sun.

The Essential Energy of Sunlight

EM Basics

Quantum Light: Enter the Photon

Spectral Properties of Sunlight

Solar Availability

Solar Intensity

Conservation of Etendue

Directionality of Sunlight

Solar Thermal Basics

High-Temperature Solar Thermal

Efficiency of Solar Thermal Systems

Spectral Selectivity

Performance of Spectral Selectivity

What Are Photovoltaics?

Band Gap

Photon Absorption


Collecting Charge Carriers

Doped Semiconductors

Current in Illuminated p-n Junctions

IV Curve

Course description

This course was written in collaboration with Lee Weinstein. Lee earned his Ph.D. in Mechanical Engineering at MIT, where he conducted research in solar thermal energy generation In this course we'll examine the principal methods of harvesting energy from sunlight—concentrated solar power and photovoltaic cells—starting from fundamental physics principles. By the end of this course, you’ll be able to answer practical engineering questions surrounding multi-junction cells, materials design, and considerations in servicing utility scale electrical grids.

Topics covered

  • Absorption and Emission
  • Carnot Efficiency
  • Concentrated Solar Power
  • Detailed Balance
  • Electromagnetic Waves
  • Energy Markets
  • Photons
  • Photovoltaic Cells
  • Semiconductor Physics
  • Shockley Diode Equation
  • Solar Availability
  • Solar Spectrum

Prerequisites and next steps

You should have a basic understanding of Newtonian mechanics and the second law of thermodynamics. A working knowledge of the Boltzmann distribution would help but is not necessary.


  • Classical Mechanics