We report on the synthesis, characterization, and photophysical investigation of a new nine-coordinate Eu 3+ complex containing three tridentate ligands and exhibiting one of the highest emission quantum yields (Φ = 85 %) so far reported in solution. Ligand field theory (LFT) and semiempirical calculations were employed to predict the energies of the 7 F JM J stark levels of the ion with the aim to find the best geometry[a] São Carlos

Aiming at the design of new luminescent host-guest materials with minimized aggregation effects, two classes of sol-gel derived mesoporous materials were explored as hosts for Rhodamine 6G (Rh6G) dye: The first consists of pure (SiO2) and phenyl-modified silica (Ph0.17SiO1.915) xerogels, prepared via sol-gel reaction using an ionic liquid as catalytic agent. The second consists of mesoporous sodium aluminosilicate glasses with Si to Al ratio in the range of 6 ≤ Si/Al ≤ 9. Characterization through high resolution solid state NMR proved the successful obtention of the designed host matrices. Following Rh6G-loading in various concentrations, the resulting materials were characterized by their luminescence and excitation spectra, excited state lifetimes, and quantum yields. The dye doped silica xerogels presented high quantum yield values (up to 87%), with no substantial decrease in efficiency with increasing dye concentration. At suitable Rh6G contents, all the final materials presented laser action under 532 nm excitation from a Q-switched frequency doubled Nd:YAG laser. The phenyl silicate sample presents the highest laser photostability with a half-life of 6560 pulses, under 2 mJ/pulse pump power, and 10 Hz repetition rate. The laser experiments provided further insights on the photodegradation mechanisms of such organic species.

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This work presents the design, preparation, and characterization of a very efficient solid state luminescent material based on a cationic bis-cyclometalated Ir(III) complex [Ir(dfptrBn)2(dmbpy)]+ (dfptrBn = 1-benzyl-4-(2,4-difluorophenyl)-1H-1,2,3-triazole; dmbpy = 4,4′-dimethyl-2,2′-bipyridine) encapsulated in sodium aluminosilicate mesoporous sol–gel glasses via the ion exchange process. The optical properties of the Ir(III) complex were fully characterized in solution and in the mesoporous solid host. The employed approach resulted in irreversible encapsulation of the complex and superior photophysical properties, such as increased photoluminescence lifetime values. Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations were carried out to understand how the chemical environment around the Ir(III) complex influences its photophysical properties. In particular, we show that in low-polarity media (ε < 20) the coupling between the cationic Ir(III) complex and the counterion appreciably affects its electronic structure.

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Pectin-based membranes with different salts such as

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