MD/QC Simulation of the Structure and Spectroscopic Properties of α‐NPD–BAlq Exciplexes at an α‐NPD/BAlq Interface in OLEDs
By Igor Anger, Elena Rykova, Alexander Bagaturyants.
The structure and spectroscopic properties of exciplexes formed at an interface between a hole‐transporting layer of N,N′‐di(naphthalen‐2‐yl)‐N,N′‐diphenyl‐benzidine (α‐NPD) and an electron transporting layer of bis(2‐methyl‐8‐quinolinato)(4‐phenylphenolato)‐aluminum (BAlq) in an OLED are investigated by multiscale (molecular dynamics, MD, and quantum chemistry, QC) simulations. Four α‐NPD–BAlq pairs with different orientations of components are selected from the central 5‐nm slab with the interface for subsequent QC calculations. Calculations for these pairs are performed within DFT/PBE0 and DFT/BHandHLYP approaches for the ground state and TDDFT/PBE0 and TDDFT/BHandHLYP approaches for the excited state with inclusion of D3BJ dispersion corrections. The calculated binding energies of the complexes are in the range from –19.0 to –24.7 kcal/mol in the ground state and from –21.9 to –34.1 kcal/mol in the excited state. The calculated S1 excited states are characterized by strong intermolecular charge transfer, and the corresponding S1→S0 transition energies are in good agreement with the available experimental data.