Temperature Dependence of Crystalline Tetracene Fluorescence

Abstract

A 100-fold increase in the fluorescence emission of crystalline tetracene is observed on cooling from room temperature to 4°K. Phase transformations and lattice distortions are reflected in a drastic change of the emission spectra: the high-temperature modification has an emission that resembles closely tetracene dimer fluorescence while the low-temperature modification fluorescence is nearly a mirror image of the absorption spectrum. The changes in the quantum yields are interpreted on the basis of the Dexter–Fowler model which predicts a considerable difference in the rates of radiationless transitions from different vibronic states.

Effect of Magnetic Field on the Fluorescence of Tetracene Crystals: Exciton Fission

“…There is evidence that the fluorescenceemitting state in crystalline tetracene is a dimer. 12 The fluorescence increases exponentially with decreasing temperature; in the temperature range 160-298°K, the activation energy is 0.16 eV. For temperatures <160°K, the activation energy is 0.006 eV.…”

On dimers and complexes of tetracene and the Kasha's molecular excitonic model

“…Among the multiple absorption spectra of the tetracene aggregates published, none reproduces the spectrum shown in Figure (a), which is assigned to the dimer spectrum; for example, the aggregate spectrum shown by Katul and Zahkan in Figure (b) of their work does not resemble ours. It is important to point out that the closest spectra to that of Figure (a) are those recorded with tetracene samples generated by vacuum‐deposited film .…”

“…It shows a clear maximum at 537 nm. We should note that the fluorescence spectra assigned to the dimeric form of tetracene by Katul and Zahlan is centered around 570 nm in the mixture diethyl ether(five parts by volume) plus ethyl alcohol (two parts) at 77 K and at 568 nm in the glass. Fournie et al .…”

“…Theoretical efforts to analyse the structure of the dimers formed by these polyacenes have been made both theoretically as spectroscopically and have focused mainly on anthracene and tetracene . Information on the spectral behaviour of tetracene as essential for the design of electronic devices is insufficient, and therefore, it needs to be further studied.…”

“…[26] Theoretical efforts to analyse the structure of the dimers formed by these polyacenes have been made both theoretically [27,28] as spectroscopically and have focused mainly on anthracene [27,[29][30][31][32][33][34][35][36] and tetracene. [37][38][39][40][41][42][43][44][45][46][47] Information on the spectral behaviour of tetracene as essential for the design of electronic devices is insufficient, and therefore, it needs to be further studied. The analyses previously made do not yield evidence that demonstrates that two polyacene molecules form a dimer, and the corresponding kinetics of the dimer or other molecular complexes have been scarcely investigated.…”