Free online coursePhysics of Solar Energy Conversion

Course Description

Solar energy technologies are often introduced through applications and device types, but their performance is ultimately determined by a set of core physical ideas. This course helps you develop that foundation, connecting fundamental physics to how solar cells and related devices generate voltage, current, and usable power. By the end, you should feel more confident reading energy band diagrams, reasoning about charge movement, and interpreting what limits real-world efficiency.

You will start by building an intuitive picture of energy levels and how they describe electronic behavior in materials. Concepts such as the Fermi level and work function are presented as practical tools: they explain why electrons move, how contact potentials form, and what a voltmeter is actually measuring. With these ideas in place, the course moves to surfaces and interfaces, where many key losses and opportunities originate. You will learn how absorption and emission relate to electronic states, and why the optical and electronic views of a material must be treated together when designing high-performance devices.

A major focus is understanding junctions, because junction physics is the backbone of photovoltaic operation. The course develops the equilibrium picture for semiconductor junctions and extends it to semiconductor–electrolyte interfaces that appear in electrochemical and photoelectrochemical systems. You will see how space charge forms, how electric fields are screened, and how these fields influence carrier motion. From there, transport mechanisms are introduced with clarity: drift and diffusion are treated as complementary processes that govern charge extraction, shaping device behavior under illumination and load.

To evaluate real devices, you will examine carrier injection and recombination, including trap-assisted pathways that commonly limit performance. These processes are tied directly to measurable outcomes such as photovoltage, photocurrent, and the current–voltage curve of a solar cell. As you progress, you will connect selective contacts, diode operation, and light-driven carrier populations to key metrics like open-circuit voltage, fill factor, and maximum power point. The course also emphasizes the link between bandgap choice and photon harvesting, helping you understand why some materials produce higher voltages while others deliver more current.

Throughout, the emphasis stays on the physical story behind efficiency: what sets the theoretical ceiling, why practical devices fall short, and which mechanisms most strongly degrade performance. You will also encounter principles of light management and strategies that can increase photocurrent by improving optical absorption and reducing losses. Combined with short conceptual exercises, this course is well suited for students and curious learners who want a rigorous, device-relevant pathway into the physics behind modern solar energy conversion.