Introduction to Solar Cells

Solar cells generate electrical energy upon exposure to solar light. This works on the principle of the photovoltaic effect which is a physical and chemical phenomenon. When the light is absorbed by a material (typically a semiconductor material with a bandgap less than the incident light photon energy), electron-hole pairs are generated. These generated electrons and holes are collected in an external circuit producing electricity.

Depending upon the type of solar cell, electron and hole collection mechanisms vary. Organic materials are widely used to collect these charge carriers (electrons and holes) in the external circuit. In dye-sensitized and perovskite solar cells, organic materials are used as electron and hole transport materials. In organic solar cells, the organic materials serve a two-fold purpose; generating electron-hole pair upon light exposure, and transporting the electrons and holes to the respective contacts connected to the external circuit.