Photovoltaic effect is the phenomenon where light energy, typically from the sun, is converted directly into electricity at the atomic level in a material. This conversion occurs when photons, the particles of light, strike semiconducting materials such as silicon and excite electrons to a higher energy state, creating electron-hole pairs that generate an electrical current. This fundamental interaction is the cornerstone of solar cell technology.
The effect was first observed in 1839 by French physicist Edmond Becquerel, yet it was not until the mid-20th century that practical applications emerged. Modern solar cells harness this effect using layers of semiconductor materials with differing electronic properties to create a built-in electric field. When light energises these layers, the field drives the flow of electrons, creating a current and electrical power. Performance and efficiency of these cells are influenced by the material properties, such as band gap energy, and the quality of the semiconductor’s crystalline structure.
Advanced applications of the photovoltaic effect include development of multi-junction solar cells, which capture broader wavelengths of light, and the integration of transparent photovoltaic materials in windows and flexible substrates. These innovations aim to maximise energy capture while integrating seamlessly into various environments.
