Theoretical Assessment of Corannulene-Based Aggregates as High-Performance Nonlinear Optical Materials

Abstract

The growing use of nonlinear optical (NLO) materials in various fields has generated interest in designing innovative smart NLO materials. This study focuses on enhancing the nonlinear optical response through doping of alkali metals on the corannulene (C20H10) dimer through Density Functional Theory (DFT) calculations. The interaction energies calculated computationally confirm the stability of the newly designed alkali metal-doped cncx dimers. Alkali metal doping, particularly with Li, Na, and K, leads to a significant reduction in the E(H–L) gap, and the lowest energy gap of 3.17 eV is observed in K-doped cncx dimer. The TD-DFT study shows that these alkali metal doped complexes have λmax in the visible regions(568-576nm). Total density of states (TDOS) spectra support the involvement of dimer in forming new Highest Occupied Molecular Orbital (HOMO). Natural Bond Orbital (NBO) analysis validates substantial charge transfer from alkali metals to dimer, with the highest charge transfer (0.938 |e|) observed in the K@cncx complex. Doping with alkali metals enhances the first hyperpolarizability, and Li@cncx exhibits the highest value (9.3×104 au). The study also determines frequency-dependent Second Harmonic Generation (SHG), Electric-Optical Pockels Effect (EOPE), electro-optic dc-Kerr effect (EOKE). The value of 3.4×104 au is observed for SHG, while for EOPE the value is 4.6×105 au. A significantly enhanced EOKE value (1.0 × 1010 au) is shown by Na@cncx. Additionally, these structures exhibit a high nonlinear quadratic refractive index (a maximum value of 9.9×10-18cm2 W-1). In conclusion, the study provides guidelines for computationally designing efficient and thermodynamically stable complexes for optical and optoelectronic technologies.