Fig. 1.

CT-EL at disordered organic heterointerfaces. (A) CT-EL spectra are typically only weakly current-density J dependent, as shown for MDMO-PPV:PC₆₁BM (1:4). (B) Schematic showing the higher-energy DOS sites sampled by the recombining carriers during the CT-EL experiment. CT-EL from adjacent lowest-energy DOS sites (dashed circles) is unlikely since such CT states are extremely rare. (C) Spatial DOS site distribution over a fraction (20 × 20 × 20 nm³) of a simulated volume (90 × 90 × 146 nm³) obtained by 3D kMC for MDMO-PPV:PC₆₁BM (1:4). Sites (light gray) with close-to-equilibrium energies (σ²/kT ± σ below DOS center) are highlighted by red and blue open circles (donor HOMO and acceptor LUMO, respectively). (D) Higher-energy sites relevant for charge transport and recombination (DOS site energies higher than σ²/kT + σ below DOS center; see the corresponding DOS schematic).