PV Gap

Harvey Said:

What on earth is a photovoltaic cell?!?!?!?!?

We Answered:

A solar cell (or a "photovoltaic" cell) is a semiconductor device that converts photons from the sun (solar light) into electricity. In general a solar cell that includes both solar and non-solar sources of light (such as photons from incandescent bulbs) is termed a photovoltaic cell. Fundamentally, the device needs to fulfill only two functions: photogeneration of charge carriers (electrons and holes) in a light-absorbing material, and separation of the charge carriers to a conductive contact that will transmit the electricity. This conversion is called the photovoltaic effect, and the field of research related to solar cells is known as photovoltaics.

Solar cells have many applications. They are particularly well suited to, and historically used in, situations where electrical power from the grid is unavailable, such as in remote area power systems, Earth orbiting satellites, handheld calculators, remote radiotelephones and water pumping applications. Assemblies of solar cells (in the form of modules or photovoltaic arrays) on building roofs can be connected through an inverter to the electricity grid, often in a net metering arrangement.

Jared Said:

what is the importance of the sun in a photovoltaic cell?

We Answered:

Not necessarily the sun, but any suitable light source, will allow a photovoltaic cell, as its name suggests, to convert light energy into electicial energy.
The advantage of sunlight is that it's abundant and free... :-)

Keith Said:

Given a standard photovoltaic cell, what are the optimal wavelengths of light in terms of energy conversion?

We Answered:

Spectral response curve for silicon cells? See the link below.

Note that shorter wavelength light will generate electricity, too, but since we can only harvest the electron falling the last step into the lowest quantum state, all the extra energy is lost as heat.

Vivian Said:

What is a photovoltaic cell and a photocell?

We Answered:

It's the same thing, either generates an electrical current when exposed to light.

However, when someone says photocell, they mean something meant to just sense the presence of light, like the tiny sensor that turns lights on at dusk and off at dawn.

When they say photovoltaic cell, or solar cell, they mean something that is used to generate usable energy. That usually ends up being a larger device.