Photorefractive and nonlinear optical properties of indium(III) tetra(15-crown-5)phthalocyaninate-based composites

• Published in: Protection of metals and physical chemistry of surfaces 2014-07, Vol.50 (4), p.472-479
• Main Authors: Grishina, A. D., Gorbunova, Yu. G., Krivenko, T. V., Lapkina, L. A., Savel’ev, V. V., Vannikov, A. V., Tsivadze, A. Yu
• Format: Article
• Language: English
• Subjects: Beams (structural); Characterization and Evaluation of Materials; Chemistry and Materials Science; Coefficients; Constants; Corrosion and Coatings; Gain; Industrial Chemistry/Chemical Engineering; Inorganic Chemistry; Joining; Materials Science; Mathematical analysis; Metallic Materials; Nanoscale and Nanostructured Materials and Coatings; Polyvinyl carbazole; Quantum efficiency; Tribology
• ISSN: 2070-2051; 2070-206X
• DOI: 10.1134/S2070205114040054

Photoelectric, nonlinear optical, and photorefractive properties of hybrid composite materials based on polyvinylcarbazole (PVK) and indium(III) 2,3,9,10,16,17,23,24-tetra(15-crown-5)phthalocyaninate [(15C5) 4 Pc]In(OH) are studied in detail. Field dependence of the quantum efficiency in a 7.8 μm-thick layer containing 5 at % [(15C5) 4 Pc]In(OH) is measured. The best approximation of the quantum efficiency with Onsager’s equation corresponds to a quantum yield of thermalized electron-hole pairs φ 0 = 0.01 at initial separation r 0 = 9.8 Å. Z -scan measurements in a nanosecond range showed that the electric susceptibility of [(15C5) 4 Pc]In(OH) solution in tetrachloroethane (TCE) with a concentration of 7 × 10 −4 mol/L is χ (3) = 1.34 × 10 −9 esu. The maximum coupling gain coefficient found for the material composed of PVK and 5 wt % [(15C5) 4 Pc]In(OH) at an electric-field intensity of 200 V/μm is Γ = 80 cm −1 , and the difference between the coupling gain and absorption coefficients is Γ − α = 70 cm −1 . The dependence of the coupling gain coefficient on the intensity ratio of interfering beams 1 and 2 (β = I 1 (0)/ I 2 (0)) in a composite containing 3 wt % [(15C5) 4 Pc]In(OH) is measured. An increase in β was attained by decreasing intensity of the signal beam I 2 (0) at constant intensity of the pump beam I 1 (0) = 0.15 W/cm 2 and E 0 = 214 V/μm. Within the initial segment of the curve, the coupling gain coefficient increases from 30 to 60 cm −1 ; then, the coefficient drops almost to the initial value. The data obtained show that the composite materials studied can be used in practice for correcting faded images. The combined analysis of the results obtained and similar data for gallium and ruthenium tetra-15-crown-5-phthalocyaninate complexes revealed the regularities in the change of the quantum yield of thermalized electron-hole pairs and the photorefractive coupling gain coefficient in a series of complexing metals: gallium(III), ruthenium(II), and indium(III). An increase in the molecular weight of the central metal atom is found to result in a substantial decrease in Γ and φ 0 due to the increase in the spin-orbit coupling constant.