Excited states of mixed-ligand chelates of ruthenium(II). Quantum yield and decay time measurements

1981 ◽  
Vol 103 (10) ◽  
pp. 2683-2687 ◽  
Author(s):  
W. H. Elfring ◽  
G. A. Crosby
Keyword(s):  
Quantum Yield ◽  
Excited States ◽  
Decay Time ◽  
Mixed Ligand

scholarly journals Modulation of charge transfer by N-alkylation to control photoluminescence energy and quantum yield

2020 ◽  
Vol 11 (27) ◽  
pp. 6990-6995 ◽  
Author(s):  
Andrew T. Turley ◽  
Andrew Danos ◽  
Antonio Prlj ◽  
Andrew P. Monkman ◽  
Basile F. E. Curchod ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Quantum Yield ◽  
Excited States

A versatile N-alkylation strategy controls the presence of charge-transfer excited states and the emission colour of N-heterocyclic chromophores.

scholarly journals P∩N Bridged Cu(I) Dimers Featuring Both TADF and Phosphorescence. From Overview towards Detailed Case Study of the Excited Singlet and Triplet States

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3415
Author(s):  
Thomas Hofbeck ◽  
Thomas A. Niehaus ◽  
Michel Fleck ◽  
Uwe Monkowius ◽  
Hartmut Yersin
Keyword(s):  
Quantum Yield ◽  
Decay Time ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Photo Luminescence ◽  
Delayed Fluorescence ◽  
Spin Lattice Relaxation ◽  
Zero Field ◽  
Triplet States ◽  
Spin Lattice

We present an overview over eight brightly luminescent Cu(I) dimers of the type Cu2X2(P∩N)3 with X = Cl, Br, I and P∩N = 2-diphenylphosphino-pyridine (Ph2Ppy), 2-diphenylphosphino-pyrimidine (Ph2Ppym), 1-diphenylphosphino-isoquinoline (Ph2Piqn) including three new crystal structures (Cu2Br2(Ph2Ppy)3 1-Br, Cu2I2(Ph2Ppym)3 2-I and Cu2I2(Ph2Piqn)3 3-I). However, we mainly focus on their photo-luminescence properties. All compounds exhibit combined thermally activated delayed fluorescence (TADF) and phosphorescence at ambient temperature. Emission color, decay time and quantum yield vary over large ranges. For deeper characterization, we select Cu2I2(Ph2Ppy)3, 1-I, showing a quantum yield of 81%. DFT and SOC-TDDFT calculations provide insight into the electronic structures of the singlet S1 and triplet T1 states. Both stem from metal+iodide-to-ligand charge transfer transitions. Evaluation of the emission decay dynamics, measured from 1.2 ≤ T ≤ 300 K, gives ∆E(S1-T1) = 380 cm−1 (47 meV), a transition rate of k(S1→S0) = 2.25 × 106 s−1 (445 ns), T1 zero-field splittings, transition rates from the triplet substates and spin-lattice relaxation times. We also discuss the interplay of S1-TADF and T1-phosphorescence. The combined emission paths shorten the overall decay time. For OLED applications, utilization of both singlet and triplet harvesting can be highly favorable for improvement of the device performance.

‘Excimer’ fluorescence I. Solution spectra of 1:2-benzanthracene derivatives

1963 ◽  
Vol 274 (1359) ◽  
pp. 552-564 ◽  
Keyword(s):  
Quantum Yield ◽  
Crystal Lattice ◽  
Excited States ◽  
Concentration Dependence ◽  
Fluorescence Spectra ◽  
Excimer Fluorescence ◽  
Relative Quantum Yield ◽  
Relative Quantum ◽  
Different Types ◽  
Excimer Formation

Observations have been made of the concentration dependence of the fluorescence spectra of solutions of 1:2-benzanthracene and fifteen of its hydrocarbon derivatives. All of the compounds, except the 9,10-dim ethyl derivative, exhibit dim er emission at higher concentrations. The lower excited states, 1 L b and 1 L a , satisfy Förster’s conditions for fluorescent dim er formation. The factors determining the relative quantum yield of excimer fluorescence are discussed. The different types of crystal fluorescence spectra shown by the compounds are explained in terms of excimer formation in the crystal lattice.

Die Abklingdauer der Fluoreszenz von Naphthalin-Kristallen

1967 ◽  
Vol 22 (8) ◽  
pp. 1242-1246 ◽  
Author(s):  
T. B. El-Kareh ◽  
H. C. Wolf
Keyword(s):  
Simple Model ◽  
Quantum Yield ◽  
Temperature Dependence ◽  
Electronic State ◽  
Oscillator Strength ◽  
Short Duration ◽  
Decay Time ◽  
Fluorescence Decay ◽  
Sample Thickness ◽  
Fluorescence Decay Time

The fluorescence decay time of naphthalene crystals has been measured as a function of sample thickness (1 μ-1 cm) and temperature (4.2°K-300°K) when excited in the first electronic state with UV pulses of short duration. A simple model is proposed to explain the decay mechanism, assuming constant quantum yield and oscillator strength and taking into account both Davydov-levels A and B. The reabsorption is found to be directly proportional to the temperature. The decay time of the lower Davydov-component can be measured directly as τA = (115 ± 5) nsec. The decay time of the higher level B is calculated from the dependence on the thickness as τB = (20 ± 10) nsec, and from the temperature dependence as TB= (30 ± 10) nsec.

Photolysis of Thiolane Vapor

1971 ◽  
Vol 49 (8) ◽  
pp. 1316-1320 ◽  
Author(s):  
Silvia Braslavsky ◽  
Julian Heicklen
Keyword(s):  
Quantum Yield ◽  
Excited States ◽  
Room Temperature ◽  
Major Product ◽  
Unstable Product

The photolysis of thiolane vapor [Formula: see text] was studied at room temperature with 2139 Å radiation. The major product was C2H4, whose quantum yield decreased as the pressure was increased. Next in importance were 1-C4H8, C3H6, and C2H6. Also produced were CH4, c-C3H6, 1,3-C4H6, CH2CHSH, [Formula: see text], 1-C4H9SH, H2, C3H8, n-C4H10, c-C4H8, polymer, and an unstable product tentatively identified as 1-butene-1-thiol. All products were initial products of the reaction. Experiments with added C3H6 showed the absence of sulfur atoms. The results are interpreted in terms of two excited states and an intermediate which might be the diradical •CH2CH2CH2CH2S•.

Sign in / Sign up

Export Citation Format

Share Document