Effect of Dimethyl Sulfoxide Additive on the Energy-Level Alignment of the PEDOT:PSS/C₆₀ Interface

Poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) has been extensively investigated as a polymeric electrode material for flexible, stretchable electronic devices.The addition of dimethyl sulfoxide (DMSO) increases the conductivity of PEDOT:PSS.However, the addition can also alter the surface electronic structure and affect its energy-level alignment with organic semiconductors, which is crucial for device performance.In this study, the impact of DMSO on the energy-level alignment of the PEDOT:PSS/C 60 interface was investigated.Insitu ultraviolet and X-ray photoelectron spectroscopy analyses revealed that DMSO increases the work function of PEDOT:PSS by 0.15 eV and alters the electron and hole-injection barriers to C 60 .In pristine PEDOT:PSS, the electron and hole-injection barriers were 0.72 and 1.53 eV, respectively.In DMSO-modified PEDOT:PSS, these barriers were 0.81 and 1.44 eV, respectively.These results highlight the effect of additive modifications on the energy-level alignment of PEDOT:PSS.