An organic solar cell converts light into electrical output using organic <semiconductors>, such as conjugated molecular or polymeric absorbers. Light absorption commonly produces a bound <exciton>, so useful charge generation requires more than simply creating an excited molecule.

In a donor–acceptor design, an <exciton> reaches an interface where charge transfer can separate its <electron> and <electron hole>. Selective contacts collect the separated <charge carriers> before they undergo <recombination>. A <bulk heterojunction> distributes donor–acceptor interfaces throughout the absorber, shortening the distance an <exciton> must travel. Its morphology must also supply connected transport pathways to the contacts. Absorption, <exciton diffusion length>, separation and charge collection therefore constrain performance together.


 Organic solar cell (source code)