Ace the NABCEP PV Associate Exam 2026 – Shine Bright in Solar Success!

The photovoltaic effect occurs in the p-n junction of the solar cell. This effect is fundamental to how solar cells convert sunlight into electricity. In a solar cell, two types of semiconductor materials are used: p-type and n-type. The p-type semiconductor has an abundance of holes (positive charge carriers), while the n-type semiconductor has an excess of electrons (negative charge carriers). When these two materials are joined, an electric field is created at the interface, or junction, between them.

When sunlight strikes the solar cell, photons from the light excite electrons in the semiconductor, allowing them to jump from the valence band to the conduction band. This creates electron-hole pairs. The electric field at the p-n junction then drives the freed electrons toward the n-type side and the holes toward the p-type side, generating a flow of electric current.

This process takes place specifically at the p-n junction, making it the critical area for the photovoltaic effect. Other layers, such as the protective glass or the surface layer of the solar panel, may serve protective or structural roles but do not participate in the generation of electricity through the photovoltaic effect. Similarly, the outer layer of the semiconductor may not be where the primary interaction with light and generation of charge carriers occurs.