Chalcone-based molecules: Experimental and theoretical studies on the two-photon absorption and molecular first hyperpolarizability

Quah

Phys. Chem. Chem. Phys.

et al. 2022

Section: Introductionmentioning

confidence: 99%

“…Several chalcone derivatives have been investigated theoretically and experimentally for their NLO properties. 6–12…”

Section: Introductionmentioning

confidence: 99%

A comprehensive study on the photophysical and non-linear optical properties of thienyl-chalcone derivatives

Quah

Phys. Chem. Chem. Phys.

et al. 2022

“…Chalcone derivatives are found to exhibit noteworthy nonlinear optical (NLO) properties accompanied by an ultrafast (picosecond–femtosecond) response. − Owing to this, chalcones have been widely studied for their possible uses in frequency conversion, two-photon absorption (2PA) spectroscopy, optoelectronics, optical power limiting (OPL), and all-optical switching (AOS) applications. − The electron donors and acceptors with π-conjugated molecular systems (D−π–A type) were often used to design molecules for larger values of first and second hyperpolarizabilities (β and γ). ,, These molecular systems of the materials depict strong charge transfer characteristics between electron donor and acceptor groups, which usually enhance the NLO properties. Therefore, it is important to know the structure–property relationships of newly prepared chalcones.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast Nonlinear Optical and Structure–Property Relationship Studies of Pyridine-Based Anthracene Chalcones Using Z-Scan, Degenerate Four-Wave Mixing, and Computational Approaches

Maidur¹,

Patil

Katturi

et al. 2021

J. Phys. Chem. B

The structural, thermal, linear, and femtosecond third-order nonlinear optical (NLO) properties of two pyridine-based anthracene chalcones, (2E)-1-(anthracen-9-yl)-3-(pyridin-2-yl)prop-2-en-1-one (2PANC) and (2E)-1-(anthracen-9-yl)-3-(pyridin-3-yl)prop-2-en-1-one (3PANC), were investigated. These two chalcones were synthesized following the Claisen–Schmidt condensation method. Optically transparent single crystals were achieved using a slow evaporation solution growth technique. The presence of functional groups in these molecules was established by Fourier transform infrared and NMR spectroscopic data. The detailed solid-state structure of both chalcones was determined from the single-crystal X-ray diffraction data. Both crystals crystallized in the centrosymmetric triclinic space group P1̅ with the nuance of unit cell parameters. The crystals (labeled as 2PANC and 3PANC) have been found to be transparent optically [in the entire visible spectral region] and were found to be thermally stable up to 169 and 194 °C, respectively. The intermolecular interactions were investigated using the Hirshfeld surface analysis, and the band structures (highest occupied molecular orbital–lowest unoccupied molecular orbital, excited-state energies, global chemical reactivity descriptors, and molecular electrostatic potentials) were studied using density functional theory (DFT) techniques. The ultrafast third-order NLO properties were investigated using (a) Z-scan and (b) degenerate four-wave mixing (DFWM) techniques using ∼50 fs pulses at 800 nm (1 kHz, ∼4 mJ) from a Ti:sapphire laser amplifier. Two-photon-assisted reverse saturable absorption, self-focusing nonlinear refraction, optical limiting, and optical switching behaviors were witnessed from the Z-scan data. 3PANC demonstrated a stronger two-photon absorption coefficient, while 2PANC depicted a stronger nonlinear refractive index among the two. The time-resolved DFWM data demonstrated that the decay times of 2PANC and 3PANC were ∼162 and ∼180 fs, respectively. The second hyperpolarizability (γ) values determined by DFT, Z-scan, and DFWM were found to be in good correlation (with a magnitude of ∼10–34 esu). The ultrafast third-order NLO response, significant NLO properties, and thermal stability of these chalcones brands them as potential candidates for optical power limiting and switching applications.

“…However, most of these investigations are purely computational and report predictions of these properties obtained by means of quantum simulations. , One of the few experimental works performed to measure two-photon absorption as well as second hyperpolarizability (γ) by four-wave mixing spectroscopy deals with only one investigated organic dye . Only more recently, several research works have reported both two-photon absorption and first hyperpolarizability (β) obtained either computationally , or by a joint computational and experimental effort , in a series of organic systems. It is noteworthy that in all of these studies, the molecular dye exhibiting the largest two-photon absorption of the series never matched the one exhibiting the largest hyperpolarizability.…”

Section: Introductionmentioning

confidence: 99%

Uncovering Structure–Property Relationships in Push–Pull Chromophores: A Promising Route to Large Hyperpolarizability and Two-Photon Absorption

et al. 2020

In this investigation, we report the first hyperpolarizabilities and two-photon absorption cross sections of a large series of 12 push–pull cationic chromophores. All of these dyes show a dipolar acceptor+–π–donor structure, where the nature of the donor and acceptor units and π-bridge was synthetically tuned to allow insightful comparisons among the molecules. The hyperpolarizability was obtained through a solvatochromic method, by exploiting the rare negative solvatochromism exhibited by the investigated compounds. The two-photon absorption cross sections were determined through two-photon excited fluorescence measurements by means of a tunable nanosecond laser system for sample excitation. The nonlinear optical properties were discussed relatively to the photoinduced intramolecular charge transfer occurring in these donor–acceptor systems, investigated by femtosecond transient absorption experiments. We found a strong increase in hyperpolarizability upon increasing the molecular conjugation. Unexpectedly, the hyperpolarizability is almost unaffected by an increase in donor/acceptor strength and intramolecular charge transfer degree. Differently, the two-photon absorption cross sections of these dyes are enhanced by an increase in both molecular conjugation and intramolecular charge transfer efficiency. Several recent literature works have reported at the same time scattered information about the hyperpolarizability and two-photon absorption of small organic molecules. Our investigation is, to the best of our knowledge, the first attempt to uncover detailed structure–property relationships for these two nonlinear optical properties. Our results represent a promising route to achieve large hyperpolarizability and two-photon absorption in push–pull dyes and may drive the design of new efficient nonlinear optical materials.