Substrate dependent charge injection at the V_2O_5/organic interface

摘要

Charge injection at the interface between V_2O_5 and N,N'-diphenyl-N,N'-bis-(1-naphthyl)-1-1'-biphenyl-4,4'-diamine (α-NPD) was studied. It is found that the energy-level alignment at the V_2O_5/α-NPD is dependent on the underlying substrate, in contrast to previous reports. This phenomenon is consistent with interface dipole theory for weakly pinning interfaces. V_2O_5 is found to weakly pin the Fermi level, such that the underlying substrate still influences the dipole between V_2O_5 and α-NPD. The charge neutrality level of V_2O_5 is also found to be 5.35 eV.