Photovoltaics: Converting solar energy into electrical power

Our sun provides us with an enormous amount of energy that exceeds the energy demand of mankind several times. Today's solar power plants, built in deserts with an extent of one seventh part the size of Germany, would be sufficient to cover the energy demand of mankind – not only in terms of electrical energy, but also including heat power and mobility.1

Tracking photovoltaic system
Concentrating sunlight, using its heat for solar thermal power generation

Solar energy can be utilized in different technical ways. In solar thermal power plants, the energy is utilized directly, or converted to electricity with the aid of steam power plants, like e.g. solar power towers. In photovoltaics, the sunlight is directly converted into electricity by appropriate semiconductors.

A solar cell absorbs sunlight, converting it into electrical power.

Two steps are necessary in organic solar cells to convert solar energy:


  1. Light absorption → creation of excitons
  2. Exciton separation → creation of electrons and holes
Conventional inorganic solar cell
Flexible organic solar cell

1: This estimation considers only the amount of energy. It does consider neither the energy for converting sunlight, nor the energy for transportation and storage. Energy storage, in particular, could double the necessary area.

2012 by OES, Johannes Widmer