The term photovoltaics can be traced back to phos (Greek: light) and volt (unit for electrical potential). Photovoltaics is therefore the direct conversion of solar radiation into electrical energy.

Light absorption: HEAT FROM LIGHT

Photons enter the material and stay there. They are neither reflected nor transmitted (emitted), but instead heat up the material. A black surface warms up more than a white surface.

Photovoltaic effect:  ELETRICITY FROM LIGHT

When light contacts a solar cell, electrons are stimulated to move and electrical voltage is induced between the side facing the light and the side turned away from the light. If the circuit is closed, electrical current flows.