Photoluminescent emission

Gorer S, Penner RM (1999) Multipulse electrochemical/chemical synthesis of CdS/S core/sheU nanocrystals exhibiting ultranarrow photoluminescence emission lines. J Phys Chem B 103 5750-5753... 

UV photoluminescence Emission bands at 495 and 430 nm with the corresponding excitation bands at 250 and 300 nm, respectively... 

The photoluminescence emission maxima (measurements in dichlor-omethane) for styryl derivatives 360-363 are given (97AM233). 

The /3-diketonate [Nd(dbm)3bath] (see figs. 41 and 117) has a photoluminescence quantum efficiency of 0.33% in dmso-7r, solution at a 1 mM concentration. It has been introduced as the active 20-nm thick layer into an OLED having an ITO electrode with a sheet resistance of 40 il cm-2, TPD as hole transporting layer with a thickness of 40 nm, and bathocuproine (BCP) (40 nm) as the electron injection and transporting layer (see fig. 117). The electroluminescence spectrum is identical to the photoluminescence emission the luminescence intensity at 1.07 pm versus current density curve deviates from linearity from approximately 10 mA cm-2 on, due to triplet-triplet annihilation. Near-IR electroluminescent efficiency <2el has been determined by comparison with [Eu(dbm)3bath] for which the total photoluminescence quantum yield in dmso-tig at a concentration of 1 mM is Dpi, = 6% upon ligand excitation, while its external electroluminescence efficiency is 0.14% (3.2 cdm-2 at 1 mAcm-2) ... 

Figure 1. Photoluminescence emission and excitation spectrum for benitoite showing Ti + luminescence.

Figure 5. Triboluminescence Spectrum of Uranyl Nitrate Hexa-hydrate. The photoluminescence excitation spectrum is shown for comparison the photoluminescence emission has been...

Figure 3. Hot photoluminescence intensity vs. time from GaAs. The pulse on the left is a calibrating 0.53 pulse arriving at the camera prior to the photoluminescence emission from GaAs.

Interest surged in studies of fluorescence after the discovery of electroluminescence from PPV (Burroughes et al., 1990), because of its potential for practical application in light emitting devices (LEDs). Electroluminescence is fluorescent emission produced by the recombination of electrons and holes injected into a thin film of conjugated polymer, and will be discussed in the next section. If photoluminescent emission from a polymer is weak, then the electroluminescence is unlikely to be of practical significance, and consequently studies of photoluminescence and photoluminescent quantum efficiency have been used as a means of selecting polymers likely to be useful in LEDs. 

Figure 1. Photoluminescence emission (A =441nm)spectra of in SrBP05. 0.04Pr,...

Rare earth hydroxides themselves find scarce applications, because of their instability in the presence of CO2. In addition, the presence of OH introduces deterioration effects for photoluminescence emissions. However, rare earth hydroxides can be easily converted into a number of other rare earth compounds through dry and solution chemical routes, therefore, they are often taken as intermediates for the s)mthesis of rare earth oxides, sulfides, and fluorides. 

The modem silicon-based microelectronics led to the miniaturization of electronic devices. However, delays caused by metallic intercoimec-tions became a bottleneck for the improvement of their performances. One possible solution of this problem is to use optical intercoimections for the transfer of information, and, therefore, silicon compatible materials and devices that are able to generate, guide, amplify, switch, modulate, and detect light are needed. Rare earth silicates with luminescent rare earths and compatibility with silicon may be a good choice for these applications (Miritello et al., 2007). Miritello et al. presented the study on nanocrystalline erbium silicate thin films fabricated on silicon/silica substrates. The obtained films exhibit strong photoluminescence emission around 1540 nm with room temperature excitation by 488 ran Ar laser. 

The photoluminescence emission based on the terbium ion peaks at 491, 549, 582, and 618 nm correspond to the f-felectronic transitions 4 Fe, D4 ->- F5, D4 F4, and D4 ->- F3, respectively (Figure 11.16). Among them, D4 -> F5 is dominant, hence a bright green emission can be observed when terbium complexes are used as emission materials. 

F ure 3 Absorption (open triangles) and photoluminescence emission (open circles) spectra for a poly( p-phenylenevinylene) film at low temperature (75 K). 

UV absorption and photoluminescence emission maxima of compounds 5 - 8 are listed in Table 2 together with the corresponding data for dodecamethylcyclohexasilane. The first maxima appearing at the low-energy side of the absorption spectra are shifted bathochromically with increasing number of siloxy groups because of enhanced a(Si-Si)—>n(0) conjugation. 

For these purposes different spectral methods have been widely used, among them the UV-visible absorption and emission spectroscopy proved to be very informative [2, 3], The investigation of the ground-state absorption and photoluminescence emission spectra of adsorbed probe molecules have been successfiil in the study of the electron-and charge-transfer reactions within zeolites. 

The observed n-n transition is therefore the result of an optical excitation with the dipole moment parallel to the PPP chains. The above-described anisotropy of the optical absorption is also valid for photoluminescence emission and can be used to obtain polarized electroluminescence (EL) spectra from Langmuir-Blodgett... 

Another absorbing species present both in photo excited and electrically excited para-phenylenes are polarons. In Fig. 8.9, we have summarized the absorption and emission spectra encountered in para-hexaphenyl (1) the triplet absorption, (2) the stimulated emission observed in time-resolved experiments with a 200-fs resolution, (3) the polaron absorption, and (4) the continuous-wave photoluminescence emission. A clearer picture for the polaronic state can be derived from experiments on the ladder-type PPPs. 

Stokes shift. Another possibility is that the optical excitation occurs from a negatively charged (D ) gap state to a D gap state, where there is initial non-radiative loss of energy to a stable D configuration. Photoluminescent emission takes place bringing the electron back to the D centre. This is illustrated in Figure 8.16 schematically. This type of... 

Figure 1. Photoluminescence emission spectra (PL) and photoluminescence excitation spectra (PLE) of CdSiMn nanocrystals embedded in a polymer film.

Photoluminescent emission takes place bringing the electron back to the D centre. This is illustrated in Figure 8.16 schematically. This type of... 

Fig. 5 Comparison between application of (18) to tin dioxide and experimental data - obtained by photoluminescence emission and particle radius by TEM measurements (from Eee et al. [79]). The inset in the figure shows an scheme of the photoluminescence emission (adapted from [82])...

Fig. 8. Photoluminescence emission efficiency as a function of temperature for three representative layered films from the same series as in Fig. 4 with a-Si H layer thickness L, 40(A). 12 ( ), and 8 A (O).

A series of ZnSe quantum dots was prepared of a range of sizes, with diameters from approximately 1.5 to 4.5 nm, and the photoluminescence emission spectra were recorded. Were the lowest energy emission bands produced by the largest or smallest quantum dots Explain. (See V. V. Nikesh, A. D. Lad, S. Kimura, S. Nozaki, S. Mahamuni, J. Appl. Phys., 2006,100, 113520.)... 

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