Fig. 4

Experimental and simulated Fermi level shift and conductivity upon doping. a Shift of the Fermi level with respect to the HOMO onset, \(\Delta E_{\mathrm{F}}^{{\mathrm{onset}}}\), in the center of a 15 nm doped organic film with ε = 4 and various magnitude of the intrinsic disorder (σ_int) in comparison with UPS measurements²⁷ of MeO-TPD doped with fluorinated fullerene C₆₀F₃₆. Simulated curves are shifted down by 0.3 eV to account for the difference in surface and bulk polarization energies¹⁴. b Shift of the Fermi level with respect to the HOMO onset, \(\Delta E_{\mathrm{F}}^{{\mathrm{onset}}}\), computed for a bulk material. c, Conductivity as a function of the DMR in doped bulk systems with ε = 4 and various intrinsic disorder strengths in comparison with experimental data^{16, 28} for low and highly disordered materials at an electric field strength of 0.04 V nm⁻¹. In the moderate doping regime (10⁻³ < DMR < 10⁻¹), the conductivity increases either sublinearly (low disorder) or superlinearly (high disorder) upon doping