Solar Cells convert sunlight (photons) into electricity (voltage). Just like computer chips solar cells have semiconducting material, when sun is absorbed by this material, the solar energy separates electrons from their atoms, which allows the electrons to flow through the material to produce electricity. This process is called photovoltaic effect. Solar cells convert energy as long as there is sunlight although they do not store energy. Energy is stored using batteries.
There is a less common way of using photovoltaics today, which is called concentrated photovoltaics (CPV), these cells are built into concentrating collectors that use a lens to focus the sunlight onto cells. CPV systems require more spending to focus on a small PV area because they would need concentrating optics, solar trackers and cooling systems. The fact that these systems cost more makes them less common today.