Lecture

Solar Cells: Band Diagrams and Efficiency

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Description

This lecture discusses the principles of a single solar cell, focusing on its band diagrams under different illumination conditions. The instructor explains the structure of a solar cell, including the p-n junction and the role of the load. The lecture covers how illumination generates electron-hole pairs, affecting the depletion region and the built-in voltage. The impact of weak and strong light on the solar cell's performance is analyzed, highlighting the relationship between current and voltage. The instructor compares monocrystalline and amorphous silicon, detailing their respective efficiencies and the trade-offs between current and voltage output. The lecture concludes with a discussion on the maximum efficiency of solar cells, emphasizing the importance of photon energy and thermal losses. Practical applications, such as solar calculators, are also mentioned, illustrating the relevance of solar cell technology in everyday devices.

Official source

Ontological neighbourhood

Energy engineering

Solar power: Topics in solar power

Physics

Condensed matter physics: Solid-state physics

Related concepts (32)

P–n junction

A p–n junction is a boundary or interface between two types of semiconductor materials, p-type and n-type, inside a single crystal of semiconductor. The "p" (positive) side contains an excess of holes, while the "n" (negative) side contains an excess of electrons in the outer shells of the electrically neutral atoms there. This allows electric current to pass through the junction only in one direction.

Solar energy

Solar energy is radiant light and heat from the Sun that is harnessed using a range of technologies such as solar power to generate electricity, solar thermal energy (including solar water heating), and solar architecture. It is an essential source of renewable energy, and its technologies are broadly characterized as either passive solar or active solar depending on how they capture and distribute solar energy or convert it into solar power.

Depletion region

In semiconductor physics, the depletion region, also called depletion layer, depletion zone, junction region, space charge region or space charge layer, is an insulating region within a conductive, doped semiconductor material where the mobile charge carriers have been diffused away, or have been forced away by an electric field. The only elements left in the depletion region are ionized donor or acceptor impurities. This region of uncovered positive and negative ions is called the depletion region due to the depletion of carriers in this region, leaving none to carry a current.

Multi-junction solar cell

Multi-junction (MJ) solar cells are solar cells with multiple p–n junctions made of different semiconductor materials. Each material's p-n junction will produce electric current in response to different wavelengths of light. The use of multiple semiconducting materials allows the absorbance of a broader range of wavelengths, improving the cell's sunlight to electrical energy conversion efficiency. Traditional single-junction cells have a maximum theoretical efficiency of 33.16%.

Solar cell

A solar cell, or photovoltaic cell, is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical phenomenon. It is a form of photoelectric cell, defined as a device whose electrical characteristics, such as current, voltage, or resistance, vary when exposed to light. Individual solar cell devices are often the electrical building blocks of photovoltaic modules, known colloquially as solar panels.

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