First Principles Study of Linear and Nonlinear Optical Properties of 2-Aminofluorene ($ C_{13} %$ H_{11} $N)

Abstract In this study, electronic band structure, linear and nonlinear optical properties of crystalline 2-aminofluorene are calculated following the density functional theory. The exchange correlation effects are taken into account by generalized gradient approximation and modified Becke–Johnson p...
Ausführliche Beschreibung

Abstract In this study, electronic band structure, linear and nonlinear optical properties of crystalline 2-aminofluorene are calculated following the density functional theory. The exchange correlation effects are taken into account by generalized gradient approximation and modified Becke–Johnson potential. In order to show the excitonic effects, we have used the recently published bootstrap exchange–correlation kernel within time-dependent density functional theory (TDDFT). The TDDFT results show the enhanced low-energy transitions (compared to RPA) and this phenomenon is a clear signature of excitonic effects. Our results for partial density of states show that the higher valence bands and the lower conduction bands come predominantly from the amino group. Generally, the calculated band structure has small dispersions which is a sign of weak intermolecular interactions. The calculated energy loss spectra possess plasmon peaks at around 26 eV. There is sufficient anisotropy between the components of dielectric tensor, especially in the non-absorbing spectra range, which is important for second harmonic generation (SHG). We have shown that the title crystal has a good potential for SHG in the visible region. Furthermore, we have reported the 2ω/ω intra-band and inter-band contributions to the dominant nonlinear susceptibilities. Findings indicate that these contributions have opposite signs at higher energies and nullify each other. The behavior of dominant second-order susceptibilities are studied in comparison with the absorptive parts of linear susceptibilities, and it is found that the general form of nonlinear spectra can be deduced from combinations of ε2(ω) and ε2(ω/2). Ausführliche Beschreibung