Thermally activated delayed fluorescence as a cycling process between excited singlet and triplet states: application to the fullerenes.

In efficient thermally activated delayed fluorescence (TADF) the excited chromophore alternates randomly between the singlet and triplet manifolds a large number of times before emission occurs. In this work, the average number of cycles n is obtained and is shown to have a simple experimental meaning: n+1 is the intensification factor of the prompt fluorescence intensity, owing to the occurrence of TADF. A new method of data analysis for the determination of the quantum yield of triplet formation, combining steady-state and time-resolved data in a single plot, is also presented. Application of the theoretical results to the TADF of [70]fullerenes shows a general good agreement between different methods of fluorescence analysis and allows the determination of several photophysical parameters.

[1]  Sandrina P. Barbosa,et al.  Radiation propagation time broadening of the instrument response function in time-resolved fluorescence spectroscopy , 2006 .

[2]  K. Koike,et al.  Temperature effect on inverse intersystem crossing of anthracenes , 1988 .

[3]  M. Berberan-Santos,et al.  A study of thermally activated delayed fluorescence in C60 , 1997 .

[4]  J. B. Birks,et al.  Photophysics of aromatic molecules , 1970 .

[5]  M. Berberan-Santos,et al.  Photophysical Properties of Pseudo-Dihydro Derivatives of C70 , 1999 .

[6]  M. Berberan-Santos,et al.  Effect of halogenated compounds on the photophysics of C70 and a monoadduct of C70: Some implications on optical limiting behaviour , 2001 .

[7]  B. Valeur,et al.  Molecular Fluorescence: Principles and Applications , 2001 .

[8]  S. K. Lam,et al.  Time-resolved spectroscopic study of phosphorescence and delayed fluorescence of dyes in silica-gel glasses , 1997 .

[9]  M. Okamoto,et al.  Pressure and temperature dependences of the rate constant for S1-T2 intersystem crossing of anthracene compounds in solution , 1995 .

[10]  M. Berberan-Santos,et al.  Unusually Strong Delayed Fluorescence of C70 , 1996 .

[11]  M. Berberan-Santos,et al.  Diels-Alder adducts of C-60 and resin acid derivatives: Synthesis, electrochemical and fluorescence properties , 1999 .

[12]  W. Dawson,et al.  RADIATIONALESS DEACTIVATION OF TRIPLET CORONENE IN PLASTICS. , 1967 .

[13]  M. Berberan-Santos,et al.  A linear response approach to kinetics with time-dependent rate coefficients , 1992 .

[14]  A. Maciejewski,et al.  Thermally activated delayed S1 fluorescence of aromatic thiones , 1986 .

[15]  B. Nickel,et al.  Photophysical triplet state processes of 4-H-1-benzopyrane-4-thione in a perfluoroalkane. Part 1.—Temperature dependence of unimolecular triplet decay , 1996 .

[16]  B. Nickel,et al.  The lowest triplet state of azulene-h8 and azulene-d8 in liquid solution.: II. Phosphorescence and E-type delayed fluorescence , 1993 .

[17]  B. Nickel,et al.  The lowest triplet state of azulene-h8 and azulene-d8 in liquid solution. I. Survey, kinetic considerations, experimental technique, and temperature dependence of triplet decay , 1993 .

[18]  Sergey M Borisov,et al.  Optical sensing and imaging of trace oxygen with record response. , 2007, Angewandte Chemie.

[19]  K. D. Legg,et al.  Photophysical studies on the benzophenones. Prompt and delayed fluorescences and self-quenching , 1975 .

[20]  D. Webb,et al.  Photoluminescence of solutions , 1969 .

[21]  S. Bachilo,et al.  Time-Resolved Thermally Activated Delayed Fluorescence in C70 and 1,2-C70H2 , 2000 .

[22]  Mário N. Berberan-Santos,et al.  Diffusion‐influenced excimer formation kinetics , 1991 .

[23]  R. Austin,et al.  ROTATIONAL DIFFUSION OF BIOLOGICAL MACROMOLECULES BY TIME‐RESOLVED DELAYED LUMINESCENCE (PHOSPHORESCENCE, FLUORESCENCE) ANISOTROPY , 1981, Annals of the New York Academy of Sciences.

[24]  H. Kono,et al.  On the role of low-frequency modes in the energy or temperature dependence of intersystem crossing , 1988 .

[25]  Ya‐Ping Sun,et al.  Fluorescence spectra and quantum yields of [60]fullerene and [70]fullerene under different solvent conditions. A quantitative examination using a near-infrared-sensitive emission spectrometer , 1996 .

[26]  Sergey M Borisov,et al.  An optical thermometer based on the delayed fluorescence of C70. , 2007, Chemistry.

[27]  W. E. Graves,et al.  Temperature Dependence of Phosphorescence Characteristics of Aromatic Hydrocarbons in Poly(methylmethacrylate) , 1972 .