Analysis of the phosphorescence of thianthren crystals

Abstract

The room temperature phosphorescence of crystalline thianthren in the 1.6-3.3 eV energy region has been measured using time delays going from 0.03 to 9.5 ms. The time dependence of the emission spectra which show the presence of three resolved bands, was analysed by means of a numerical best-fitting procedure, and the results obtained have been compared with those predicted by means of ab initio and semiempirical molecular orbital calculations.PACS 33.50 -Fluorescence and phosphorescence; radiationless transitions (intersystem crossing, internal conversion). PACS 72.80 -Conductivity of specific semiconductors and insulators.

Observation of Dual Room Temperature Fluorescence–Phosphorescence in Air, in the Crystal Form of a Thianthrene Derivative

“…Three components are identified in photoluminescence decay: prompt and delayed fluorescence and phosphorescence (Figure a and b). Indeed a similar observation was previously reported for thianthrene crystals, but not fully explained. In thianthrene, the prompt fluorescence decays with τ PF1 = 2.3 ± 0.1 ns and τ PF2 = 8.2 ± 0.5 ns, followed by delayed fluorescence decaying with τ DF1 = 160 ± 20 ns and τ DF2 = 15 ± 3 μs.…”

“…Three components are identified in photoluminescence decay: prompt and delayed fluorescence and phosphorescence (Figure 4). Indeed a similar observation was previously reported for thianthrene crystals, 34 (Figure 4 c). This is in contrast with the delayed fluorescence of thianthrene, which appears at slightly lower energy than the prompt fluorescence (Figure 4 d).…”

Dual‐Emission of Fluorescence and Room‐Temperature Phosphorescence for Ratiometric and Colorimetric Oxygen Sensing and Detection Based on Dispersion of Pure Organic Thianthrene Dimer in Polymer Host

“…Although these TA analogues were primarily investigated in terms of electrochemical and chemical properties in previous works, [ 25 ] the studies on their photophysical properties are still inadequate, [ 26 ] especially for their RTP properties. [ 27 ] For TA dimers, all TA units maintain the folded conformations in the crystal structures (Figures S2–S4, Supporting Information), inheriting the mechanism of folding‐induced SOC enhancement. [ 24 ] Theoretical calculations on all molecules reveal the sizable SOC coefficients between the lowest singlet (S 1 ) and the triplet (T n ) manifolds (Figures S11,S12, Table S2, Supporting Information), indicating that they have great potential as efficient RTP materials.…”

The Properties, Synthesis, and Materials Applications of 1,4-Dithiins and Thianthrenes

“…Thianthrene ( 3 ) has long been known to exhibit room-temperature phosphorescence (RTP) in the solid state. 115 Several theories have been put forth on the origin of the RTP of 3 , but recent literature indicates that it stems from folding-induced spin-orbital coupling enhancement. 115 116 Briefly, when 3 is in the solution state, the S 1 and T 1 states adopt planar geometries that give very small spin-orbit couplings.…”

“…115 Several theories have been put forth on the origin of the RTP of 3 , but recent literature indicates that it stems from folding-induced spin-orbital coupling enhancement. 115 116 Briefly, when 3 is in the solution state, the S 1 and T 1 states adopt planar geometries that give very small spin-orbit couplings. 116 In rigid media, such as the crystalline state or in a matrix, 3 cannot adopt a planar geometry upon excitation.…”