When an organic semiconductor absorbs a photon, it doesn't immediately create a free electron and hole. Instead, it creates an —a bound electron-hole pair held together by strong electrostatic (Coulombic) attraction.
. Because organic materials have a low dielectric constant, these excitons have high binding energy ( physics of organic semiconductors pdf
Mobility typically increases with temperature (unlike metals). When an organic semiconductor absorbs a photon, it
– Physics of Organic Semiconductors (Ed. Wolfgang Brütting) physics of organic semiconductors pdf