title: First Example of Nonlinear Optical Materials Based on Nanoconjugates of Sandwich Phthalocyanines with Quantum Dots.
abstract: We report original, selective, and efficient approaches to novel nonlinear optical (NLO) materials, namely homoleptic double- and triple-decker europium(III) complexes 2 and 3 with the A3B-type phthalocyanine ligand (2,3-bis[2'-(2''-hydroxyethoxy)ethoxy]-9,10,16,17,23,24-hexa-n-butoxyphthalocyanine 1) bearing two anchoring diethyleneglycol chains terminated with OH groups. Their covalently linked nanoconjugates with mercaptosuccinic acid-capped ternary CdSeTe/CdTeS/ZnSeS quantum dots are prepared in the presence of an ethyl(dimethylaminopropyl)carbodiimide activating agent. Optical limiting (OL) properties of the obtained low-symmetry complexes and their conjugates with quantum dots (QDs) are measured for the first time by the open-aperture Z-scan technique (532 nm laser and pulse rate of 10 ns). For comparison, symmetrical double- and triple-decker EuIIIocta-n-butoxyphthalocyaninates 5 and 6 and their mixtures with trioctylphosphine oxide-capped QDs are also synthesized and studied. It is revealed that both lowering of molecular symmetry and expansion of the π-electron system upon moving from double- to triple-decker complexes significantly improves the OL characteristics, making the low-symmetry triple-decker complex 3 the most efficient optical limiter in the studied family of sandwich complexes, affording 50 % lowering of light transmittance below 0.5 J cm-2input fluence. Conjugation (both covalent and noncovalent) with QDs affords further enhancement of the OL properties of both double- and triple-decker complexes. Altogether, the obtained results contribute to the development of novel nonlinear optical materials for future nanoelectronic and optical device applications.
authors.affiliation: Department of Chemistry, Rhodes University, Grahamstown, 6140, South Africa.
authors.forename: David O
authors.initials: DO
authors.lastname: Oluwole
authors.affiliation: A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr., 31, bldg. 4, Moscow, 119071, Russia.|Dmitry Mendeleev University of Chemical Technology of Russia, Miusskaya sq., 9, 125047, Moscow, Russia.
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Yagodin
authors.affiliation: Department of Chemistry, Rhodes University, Grahamstown, 6140, South Africa.
authors.forename: Nhlakanipho C
authors.initials: NC
authors.lastname: Mkhize
authors.affiliation: Department of Chemistry, Rhodes University, Grahamstown, 6140, South Africa.
authors.forename: Kutloano E
authors.initials: KE
authors.lastname: Sekhosana
authors.affiliation: A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr., 31, bldg. 4, Moscow, 119071, Russia.
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Martynov
authors.affiliation: A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr., 31, bldg. 4, Moscow, 119071, Russia.|Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii pr., 31, Moscow, 119991, Russia.
authors.forename: Yulia G
authors.identifier: http://orcid.org/0000-0002-2333-4033
authors.initials: YG
authors.lastname: Gorbunova
authors.affiliation: A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr., 31, bldg. 4, Moscow, 119071, Russia.|Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii pr., 31, Moscow, 119991, Russia.
authors.forename: Aslan Yu
authors.initials: AY
authors.lastname: Tsivadze
authors.affiliation: Department of Chemistry, Rhodes University, Grahamstown, 6140, South Africa.
authors.forename: Tebello
authors.identifier: http://orcid.org/0000-0002-4590-9926
authors.initials: T
authors.lastname: Nyokong
keywords: nonlinear optics; phthalocyanines; quantum dots; sandwich complexes; two-photon absorption