Second harmonic generation on crystalline organic nanoclusters under extreme nanoconfinement in functionalized silica-benzil composites

Houda El Karout; Yaroslav Shchur; Anatoliy Andrushchak; Bouchta Sahraoui; Robert Wielgosz; Olha Kityk; Jarosław Jędryka; Yurii Slyvka; Andriy V Kityk

doi:10.1038/s41598-023-37147-4

Second harmonic generation on crystalline organic nanoclusters under extreme nanoconfinement in functionalized silica-benzil composites

Sci Rep. 2023 Jun 19;13(1):9943. doi: 10.1038/s41598-023-37147-4.

Authors

Houda El Karout^{1

2}, Yaroslav Shchur³, Anatoliy Andrushchak⁴, Bouchta Sahraoui¹, Robert Wielgosz⁵, Olha Kityk⁵, Jarosław Jędryka⁶, Yurii Slyvka⁷, Andriy V Kityk⁸

Affiliations

¹ University of Angers, LPhiA, SFR MATRIX, 2 Bd. Lavoisier, 49045, Angers Cedex 01, France.
² University of Angers, MOLTECH-Anjou-UMR CNRS 6200, SFR MATRIX, 49000, Angers, France.
³ Institute for Condensed Matter Physics, 1 Svientsitskii str., Lviv, 79011, Ukraine. shchur@icmp.lviv.ua.
⁴ Lviv National Polytechnic University, 12 S. Bandery str., Lviv, 79013, Ukraine.
⁵ Energia Oze Sp. z o.o., ul. Czȩstochowska 7, 42-274, Konopiska, Poland.
⁶ Faculty of Electrical Engineering, Częstochowa University of Technology, Al. Armii Krajowej 17, 42-200, Częstochowa, Poland.
⁷ Department of Inorganic Chemistry, Ivan Franko National University of Lviv, Kyryla i Mefodiya Str. 6, Lviv, 79005, Ukraine.
⁸ Faculty of Electrical Engineering, Częstochowa University of Technology, Al. Armii Krajowej 17, 42-200, Częstochowa, Poland. andriy.kityk@pcz.pl.

Abstract

We demonstrate a series of organic-inorganic nanocomposite materials combining the mesoporous silica (PS) and benzil (BZL) nanocrystals embedded into its nanochannels (6.0-13.0 nm in diameter) by capillary crystallization. One aims to design novel, efficient nonlinear optical composite materials in which inactive amorphous host PS-matrix provides a tubular scaffold structure, whereas nonlinear optical functionality results from specific properties of the deposited guest BZL-nanocrystals. A considerable contraction of the BZL melt during its crystallization inside the silica nanochannels results in a formation of the texture consisting of (221)- and (003)-oriented BZL nanoclusters (22 nm in length), separated by voids. Specificity of the textural morphology similarly to the spatial confinement significantly influences the nonlinear optical features of composite PS:BZL materials being explored in the second harmonic generation (SHG) experiment. The light polarization anisotropy of the SHG response appears to be considerably reduced at channel diameters larger than 7 nm apparently due to the multiple scattering and depolarization of the light on randomly distributed and crystallographically oriented BZL-nanoclusters. The normalized SHG response decreases nonlinearly by more than one order of magnitude as the channel diameter decreases from 13.0 to 6.0 nm and vanishes when spatial cylindrical confinement approaches the sizes of a few molecular layers suggesting that the embedded BZL clusters indeed are not uniformly crystalline but are characterized by more complex morphology consisting of a disordered SHG-inactive amorphous shell, covering the channel wall, and SHG-active crystalline core. Understanding and controlling of the textural morphology in inorganic-organic nanocrystalline composites as well as its relationships with nonlinear optical properties can lead to the development of novel efficient nonlinear optical materials for the light energy conversion with prospective optoelectronic and photonic applications.

Abstract

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