Phosphorescence energy diagram

Figure Bl.1.3. State energy diagram for a typical organic molecule. Solid arrows show radiative transitions A absorption, F fluorescence, P phosphorescence. Dotted arrows non-radiative transitions.

Figure 3.1 Schematic energy diagram for phosphorescence and fluorescence.

Figure 12.1—Energy diagram comparing fluorescence and phosphorescence. Short arrows correspond to internal conversion without the emission of photons. Fluorescence is an energy transfer between states of the same multiplicity (spin state) while phosphorescence is between states of diiferent multiplicity. The situation is more complex than that shown by this Jablonski diagram.

Figure 23-14 Potential energy diagram for the ground state S0 and the first excited singlet S, and triplet Tj states of a representative organic molecule in solution. G is a point of intersystem crossing Sj —> T,. For convenience in representation, the distances r were chosen rS() < rSj < rT thus, the spectra are spread out. Actually, in complex, fairly symmetric molecules, rS(. rs < rT and the 0-0 absorption and fluorescence bands almost coincide, but phosphorescence bands are significantly displaced to the lower wavelengths. From Calvert and Pitts,2 p. 274.

Fig. 15. (A) Absorption, fluorescence and phosphorescence spectra of BChl a in vitro at 77 K spectra scaled for convenient presentation also note break of horizontal scale (B) Phosphorescence spectrum of quinone-depleted (-Q) and quinone-containing (+Q) Rb. sphaeroides reaction centers in polyvinyl-alcohol film at 22 K (C) Energy diagram for the components involved in triplet-triplet energy transfer with carotenoids. (A) and (B) and numerical values for the triplet-state energies of BChls a and b and the primary-donors of Rb. sphaeroides and Rp. viridis, i.e., [BChl a and [BChl bjj, respectively, are taken from Takiff and Boxer (1987) Phosphorescence spectra ofbacteriochlorophylls. J Am Chem Soc 110 4425.

Figure 11.2 Energy diagram comparingfluorescenceandphosphorescence.Theshoitaxiowscoue-spond to mechanisms of internal conversion without emission ofphotons. The fluorescence results from transfers between states of the same multiplicity (same spin state) while the phosphorescence results from transfers between states of different multiplicity. The state Tj produces a delay in the return to the fundamental state, which can last several hours. The Stokes shift corresponds to the energy dissipated in the form of heat (vibrational relaxation) during the lifetime of the excited state, prior to photon emission. The real situation is more complex than this simplified Jablonski diagram suggests. To our scale, a compound can be both fluorescent and phosphorescent for, at the molecular scale individual species do not all exhibit the same behaviour.

Figure 7. Generic energy diagrams for a strong-field Crm complex. Phosphorescence is P, from the double Dy and the fluorescence Fl from the quartet Qv...

Figure 4.4 Jablonski-type energy diagrams for possible excited energy states when light interacts with matter, (a) Three possible transition pathways for return to ground state without radiation, (b) Two possible transition pathways with fluorescent light emission as final step on return to ground state, (c) Two possible transition pathways with phosphorescent light emission as final step on return to ground state.

Figure 2.24 Energy diagram for both fluorescence and phosphorescence in a molecule (Following absorption of radiation, an electron is promoted into the excited singlet state. Following radiationless loss of energy, the electron moves by inter-system crossing (ISC) to the excited triplet state, from where it can phosphoresce. As can be seen from the diagram, internal conversion (1C) and other ISC transitions are possible between states).

Show by means of an energy diagram the reason that the energy of light emitted from an excited electronic state by fluorescence or phosphorescence... 

Draw a molecular-energy diagram showing the transitions involved in the phosphorescence of anthracene, which occurs at 680 nm. 

Fig. 11.9 The Structure and energy diagram of a high-efficiency phosphorescent OLED made with several organic layers. The energy diagram on the upper right shows the non-radiative population of the triplet state of lr(ppy)3, from which the electroluminescence is emitted. The diagram is drawn for an applied voltage of V = -Vg/. After [10].

Figure 2.14. The potential energy diagram of the lower states of trivalent chromium. At left the state energies vs. the position of the nuclei of the metal and the ligands. Arrows denote optical transitions a means absorption, / is fluorescence, p is phosphorescence (the dashed line is spin-forbidden). Laser function can also be represented in a diagram as shown on the right.

On the basis of the overall results, an energy diagram for CT-allowing AN-s-BPDA-AN can be depicted as shown in Fig. 19. In the proposed mechanism, the intermolecular CT fluorescence emission occurs via two different pathways first, the photoinduced electron transfer from a local excited state at the biphenyldiimide unit to the spatially adjacent ground-state PDA residue, and second, the direct excitation at the CT absorption band. The first process is possible even at very low CTC concentration as in the PI film cured at a low temperature such as 200°C. Such a photoinduced electron transfer mechanism will be theoretically discussed again later. In fully aromatic s-BPDA-PDA, both the fluorescence from Si (tt, tt ) and phosphorescence from Ti (tt, tt ) are not observed practically. The results are probably attributed to the considerably fast CT process from Si (it, tt ). 

Figure 1 State energy diagram representing possible photochemical and photophysical processes triggered by absorption of a photon A, absorption VR, vibrational relaxation F, fluorescence IC, internal conversion P, phosphorescence 1ST, intersystem crossing R, reaction.

Fig. 7.1 Simplified energy diagram of the lanthanide organic complex system. Abs. absorption, Fluor, fluorescence, Phosph. phosphorescence, EM lanthanide (Ln ) ion emission, ISC intersystem crossing, ET energy transfer, S singlet, T triplet. Non-rad. nonradiative transitions (Reproduced from Ref. [18] by permission of the Royal Society of Chemistry)...

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