Triplet-triplet absorption of eosin Y in methanol determined by nanosecond excimer laser excitation and picosecond light continuum probing

Abstract

The absolute triplet-triplet absorption cross-section spectrum a T (X) of eosin Y in methanol at room temperature is determined in the wavelength region from 400 to 1000 nm and at 308 and 1054 nm. The triplet state is populated by XeCl excimer laser excitation to a singlet state and subsequent intersystem crossing. The triplet level population is determined by numerical simulation of the pump pulse absorption dynamics. The triplet-triplet absorption is probed with picosecond spectral light continua which are generated in a D 2 0 sample by a synchronized mode-locked Nd:glass laser. The decay of the triplet level population is studied by delayed picosecond light continua probing. Second order rate constants of hQ* =* i.l X10 9 dm 3 mol~l s~l for oxygen quenching, fc&> = i.3x 10 9 dm 3 mol~l s~l for triplet-triplet annihilation, and k$ ss4x 10 8 dm 3 mol~l s" 1 for triplet-singlet concentration quenching have been determined.

Eosin Y catalysed photoredox synthesis: a review

“…The organic dye eosin Y has been found more synthetic utility in photocatalysed organic reactions due to its better yield capacity in comparison to other organic dye of uorescein family. 50 The photochemistry of eosin Y is well investigated: upon excitation by visible light, eosin Y undergoes rapid intersystem crossing to the lowest energy triplet state, which has a life time of 24 ms. [25][26][27] Eosin Y absorbs green light; the UV-Vis spectrum shows a characteristic peak at 539 nm with a molar extinction coefficient 3 ¼ 60 803 M À1 cm À1 . Upon excitation eosin Y becomes more reducing and more oxidizing compared to in its ground state.…”

Luminescent Eosin Y–SiO2 hybrid nano and microrods prepared by sol–gel template method

“…7). The spectra can be understood based on electronic energy level diagram common to all organic dyes [23] being due to transition between singlet and tripled states of the Eosin-Y dye [24]. We noticed a very good agreement between the main absorption peak and luminescence peak in the Eosin Y-SiO 2 hybrid bulk (at 517 nm and 545 nm) and in the Eosin-Y water solution at (515 nm and 545 nm) [25].…”

Picosecond Transient Absorption of Xanthene Dyes

“…In correspondence with Refs. [9,12] we assign this absorption to the triplet-triplet absorption. The relatively fast occurrence of the triplet-triplet absorption (cp.…”

“…Up to now the properties of the first excited singlet and triplet states S1, T1 and the intersystem crossing starting from S1 are well known. Reported values of fluorescence quantum yields and lifetimes as well as triplet yields for the xanthene dyes rose bengal, eosin Y and erythrosin B are summarized in Table. Recently for rose bengal, erythrosin B and eosin Y a reverse intersystem crossing process from a higher excited triplet state to the singlet system was investigated by one-colour ps-double pulse excitation spectroscopy [7][8][9]. It was shown *The results of this paper were initially presented at The Jabłoński Centennial Conference on Luminescence and Phatophysics, July 29-27, 1998, Toruń, Poland.…”