Realizing the effect of s-block metals on a charge transfer crystal of indol-2-one for enhanced NLO responses with efficient energetic offsets

• Published in: Journal of molecular modeling Vol. 30; no. 5; p. 126
• Main Authors: Hassan, Abrar U., Sumrra, Sajjad H., Mohyuddin, Ayesha, Nkungli, Nyiang K., Alhokbany, Norah
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-05-2024; Springer Nature B.V
• Subjects: Alkali metals; Characterization and Evaluation of Materials; Charge transfer; Chemistry; Chemistry and Materials Science; Chromophores; Computer Appl. in Life Sciences; Computer Applications in Chemistry; Crystals; Dichloromethane; Electron density; Free electrons; Metals; Molecular Medicine; Nonlinear optics; Offsets; Optical materials; Optical properties; Optics; Optoelectronic devices; Original Paper; Softness; Stabilization; Theoretical and Computational Chemistry; NLO; Softness; NBO; DFT; Alkali metals
• ISSN: 1610-2940; 0948-5023
• DOI: 10.1007/s00894-024-05923-2

Context
Due to their unique photophysical properties, organic charge transfer crystals are becoming promising materials for next-generation optoelectronic devices. This research paper explores the impact of s-block metals on a charge transfer crystal of indol-2-one for enhanced nonlinear optical (NLO) responses with efficient energetic offsets. The study reveals that alkali metals can enhance NLO performance due to their free electrons.
Method
The Perdew-Burke-Ernzerhof functional of DFT with dispersion correction (D3) was used, and the
λ
max
values ranged between 596 and 669 nm, with the highest value for dichloromethane (DCM). Leveraging the unique properties of metals allowed for the development of nonlinear optical materials with improved performance and versatility. Softness (
σ
) values provide insight into electron density changes, with higher values indicating a greater tendency for changes and lower values indicating the opposite. The NLO results for the chromophores MMI1–MMI6 show varying linear polarizability (< 
α
0
 >) along with their first (
β
0
) and second (
γ
0
) hyperpolarizabilities. Chromophore MMI4 stands out with the highest NLO performance, having two potassium (K) atoms. Its < 
α
0
 > ,
β
0
, and
γ
0
values of 4.19, 7.09, and 17.43 (× 10
−24
e.s.u), respectively, indicate a significant enhancement in NLO response compared to the other chromophores. The transitions involving (O20)LP → (C3-N5)π* and (O19)LP → (N12-C13)π* exhibit the highest level of stabilization, followed by (O23)π → (C10-C11)π*, while (C6-N12)π → (C6-C7)π* shows the lowest level of stabilization for chromophore MMI4. The present research work is facile in its nature, and it can be helpful for synthetic scientist to design the new materials for uniting crystal properties with metal doping for efficient NLO devices.