DFT study of alkali and alkaline earth metal-doped benzocryptand with remarkable NLO properties

Nimra Maqsood; Areeba Asif; Khurshid Ayub; Javed Iqbal; Ashraf Y Elnaggar; Gaber A M Mersal; Mohamed M Ibrahim; Salah M El-Bahy

doi:10.1039/d2ra02209e

DFT study of alkali and alkaline earth metal-doped benzocryptand with remarkable NLO properties

RSC Adv. 2022 May 27;12(25):16029-16045. doi: 10.1039/d2ra02209e. eCollection 2022 May 23.

Authors

Nimra Maqsood¹, Areeba Asif¹, Khurshid Ayub², Javed Iqbal¹, Ashraf Y Elnaggar³, Gaber A M Mersal⁴, Mohamed M Ibrahim⁴, Salah M El-Bahy⁵

Affiliations

¹ Department of Chemistry, University of Agriculture Faisalabad-38000 Pakistan Javedkhattak79@gmail.com Javed.iqbal@uaf.edu.pk.
² Department of Chemistry, COMSATS University, Islamabad, Abbottabad Campus Abbottabad 22060 Pakistan.
³ Department of Food Science and Nutrition, College of Science, Taif University Taif 21944 P. O. Box 11099 Saudi Arabia.
⁴ Department of Chemistry, College of Science, Taif University P. O. Box 11099 Taif 21944 Saudi Arabia.
⁵ Department of Chemistry, Turabah University College, Taif University P. O. Box 11099 Taif 21944 Saudi Arabia.

Abstract

Strategies for designing remarkable nonlinear optical materials using excess electron compounds are well recognized in literature to enhance the applications of these compounds in nonlinear optics. In this study, density functional theory simulations are performed to study alkali and alkaline earth metal-doped benzocryptand using the B3LYP/6-31G+(d, p) level of theory. Vertical ionization energies (VIEs), reactivity parameters, interaction energies, and binding energies exposed the thermodynamic stability of these complexes. FMO analysis revealed that HOMO is located on alkali metals having polarized electrons, which are easy to excite. The doping strategy enhanced the charge transfer with low bandgap energy in the range of 0.68-2.23 eV, which is lower than that of the surface BC (5.50 eV). Also, the lower transition energies and higher oscillator strength indicate that these complexes exhibit excellent electronic and optical properties. Non-covalent interaction analysis suggested the presence of van der Waals interactions between dopants and surface. IR analysis provided information about the frequencies of stretching vibrations present in the complexes due to different bonds. UV-vis analysis revealed that all the newly designed excess electron complexes are transparent in the UV region and possessed maximum absorption in the visible and NIR region, ranging from 753.6 to 2150 nm, which is higher than the surface (244 nm). Thus, these complexes have a potential for high-performance NLO materials in the applications of optics. Natural bond orbital analysis (NBO), transition density matrix (TDM), electron density difference map (EDDM), and density of state (DOS) analyses were also performed to study the charge transfer properties. Moreover, these complexes possessed remarkable optoelectronic properties due to a significant increase in the isotropic linear polarizability (α _iso) in the range of 629.59-1423.23 au. Further, these systems demonstrated an extraordinary large total first hyperpolarizability (β _tl) in the range of 3695.55-910 706.43 au. The rationalization of hyperpolarizability by the two-level model reflected a noteworthy increase in β _tl because of low transition energies (ΔE) and high transition dipole moment (Δμ). Thus, our results showed that alkali and alkaline earth metal-doped BC might be a competitor for efficient nonlinear optical properties with practical applications in the area of optoelectronics.