are forbidden by spin-selection rules. Triplets have much longer lifetimes than singlets because their decay back to the ground state is inefficient (phosphorescence). Exciton Diffusion
) in inorganic crystals, and the LUMO acts similarly to the conduction band edge ( Eccap E sub c
: When light is absorbed, it creates a bound electron-hole pair called an . Because of high binding energies ( physics of organic semiconductors pdf
can overcome the reorganization energy. In these rare cases, the material transitions from localized hopping to true , where mobility increases as temperature decreases. 3. Excited State Dynamics: Photophysics and Excitons
Several authoritative textbooks and review chapters are available as PDF samples or through institutional repositories: Physics of Organic Semiconductors | Wiley Online Books are forbidden by spin-selection rules
Organic semiconductors have revolutionized the field of electronics, offering a flexible, lightweight, and low-cost alternative to conventional inorganic materials like silicon. The resources often detail how these materials—typically conjugated polymers or small molecules—bridge the gap between insulators and conductors through -electron conjugation.
). The energy difference between the HOMO and LUMO defines the fundamental electronic bandgap ( Egcap E sub g Because of high binding energies ( can overcome
ket=J2ℏπλkBTexp(−(ΔG∘+λ)24λkBT)k sub e t end-sub equals the fraction with numerator cap J squared and denominator ℏ end-fraction the square root of the fraction with numerator pi and denominator lambda k sub cap B cap T end-fraction end-root exp open paren negative the fraction with numerator open paren cap delta cap G raised to the composed with power plus lambda close paren squared and denominator 4 lambda k sub cap B cap T end-fraction close paren
Instead of separating immediately into free charges, they form a tightly bound, neutral quasiparticle called an . Frenkel vs. Wannier-Mott Excitons
In perfectly ordered organic single crystals (e.g., ultra-pure rubrene) at low temperatures, charges can move via , where wavefunctions are delocalized and mobility ( ) decreases as temperature rises due to phonon scattering.