Theoretical Insights on the Electronic Properties of Eosin Y, an Organic Dye for Photovoltaic Applications

Abstract

A theoretical analysis, based on density functional theory, has been carried out on the electronic properties of eosin yellowish (2',4',5',7'-tetrabromofluorescein), a dye used for photovoltaic applications. In particular different oxidation states of the bare molecule as well as its complexes with a Zn dication have been considered, with the aim to gain some insights on its electro- and photochemical behavior. The calculations have been carried out both in the gas phase and in solution, this last modeled by a continuum model. Besides the agreement with the experimental data, our results allow for a better interpretation of the spectroscopic properties of this dye and their tuning by interaction with the solvent or metal atom in aqueous solution.

Reactivity and Mechanistic Insight into Visible‐Light‐Induced Aerobic Cross‐Dehydrogenative Coupling Reaction by Organophotocatalysts

“…Upon laser excitation by 532 nm light, a strong negative bleach of the ground-state absorption of TBA-eosin Y at ap- proximately 530 nm and characteristic absorptions at 580 nm were observed immediately, the decay of which throughout the absorption region and the recovery of the bleach occurs on the same timescale and can be thoroughly described by a monoexponential function with a lifetime of 16 ms, which is consistent with that of the triplet excited state of eosin Y derivatives in the literature. [11] Figure 2 displays the time-resolved absorption difference spectra for TBA-eosin Y and for TBA-eosin Y with 1 a, respectively. When 1 a was introduced into the solution of TBA-eosin Y, the absorptions were immediately replaced by a series of new absorptions with a maximum at 370 nm in addition to the strong triplet-state absorptions of TBA-eosin Y in the region of 500-650 nm.…”

“…When 1 a was introduced into the solution of TBA-eosin Y, the absorptions were immediately replaced by a series of new absorptions with a maximum at 370 nm in addition to the strong triplet-state absorptions of TBA-eosin Y in the region of 500-650 nm. Following from spectroscopic studies of eosin Y derivatives, [11] the transient species that absorbed at 370 nm is ascribed to the reduced TBA-eosin Y radical anion. From the kinetics probed at 370 nm, a fast rise phase followed by a slow decay suggest that the photoinduced electron transfer from 1 a to the triplet state of TBA-eosin Y led to the formation and disappearance of the TBA-eosin Y radical anion.…”

“…[10] Moreover, the rich spectroscopic properties of eosin Y are expected to allow for the detection of the intermediate during irradiation. [11] With this system, we were able to achieve the oxidative coupling products of Naryl tetrahydroisoquinolines with either nitroalkanes or dimethyl malonate and even acetone in good to excellent yields under mild conditions. Spectroscopic study and product analysis demonstrate for the first time that photoinduced electron transfer from N-aryl tetrahydroisoquinolines to eosin Y takes place to generate eosin Y radical anions, which can subsequently react with nitroalkanes and molecular oxygen.…”

Photocatalytic hydrogen evolution under visible light irradiation by the polyoxometalate α-[AlSiW11(H2O)O39]5− -Eosin Y system

“…Thus, the decrease of the activity and stability can be ascribed to debromination of EY. However, when EY is coordinated with AlSiW 11 , the atomic charges of bromine atoms would reduce greatly due to coordination effect by the Al 3þ of AlSiW 11 , which would be similar to the case of Zn-complexed EY [36]. As a result, the debromination reaction is suppressed.…”

Wavelength-tunable photoconductivity of dye-sensitized TiO_2 nanoparticle films

“…Eosin-Y, a brominebased metal free organic dye, has also been used in the dye-sensitized solar cell, due to its LUMO and HOMO [21] matching well with the CB of TiO 2 and ZnO. Photoconductivity properties for this dye-modified TiO 2 film is shown in Figs.…”