Poly photoluminescence efficiency

Whereas in solution the photoluminescence efficiency (Of) of poly(3-alkylthiophenes) (PATs) is 3(Mf)%, it drastically drops to 1-4% and lower in the solid state due to the increased contribution of nonradiative decay via interchain interactions and ISC caused by the heavy-atom effect of sulfur (97MM4608). Optoelectronic devices of this type of compounds have been studied (98SCI(280)1741 06SM(156)1241). Fibers of poly(3-hex-ylthiophene) for photovoltaic applications have been described (07MI1377). Poly(3-octylthiophene) showed a TTA band at 800 nm (96JPC15309). The photophysical properties of some alkyl and aryl polythiophenes have been studied (03JCP(118)1550). The absorption maximum of poly(3-octylthiophene) is at 438 nm, while the fluorescence was... 

Figure 11.7 depicts typical absorption and luminescence spectra for polysilanes. Absorption peak energies are within the range 3 to 4 eV and are determined mainly by backbone conformation. Photoluminescent efficiencies are high (10% to 50%) and the apparent Stokes shift increases with the breadth of the absorption spectrum. Whenever a single screw-sense helical structure pertains, the absorption and emission bands are narrow and the Stokes shift is small. Such a polymer is poly[decyl-(5)-2-methylbutylsilane], the chiral center within the (S)-2-methylbutyl substituent determining the screw sense. Such... 

Staring EGJ, Demandt RCJE, Braun D, Rikken GLJ, Kessener YARR, Venhuizen AHJ, et al. Electroluminescence and photoluminescence efficiency of poly(p-phenylenevinylene) derivatives. Synth Met 1995 71(l-3) 2179-80. 

Zinc sulfide, with its wide band gap of 3.66 eV, has been considered as an excellent electroluminescent (EL) material. The electroluminescence of ZnS has been used as a probe for unraveling the energetics at the ZnS/electrolyte interface and for possible application to display devices. Fan and Bard [127] examined the effect of temperature on EL of Al-doped self-activated ZnS single crystals in a persulfate-butyronitrile solution, as well as the time-resolved photoluminescence (PL) of the compound. Further [128], they investigated the PL and EL from single-crystal Mn-doped ZnS (ZnS Mn) centered at 580 nm. The PL was quenched by surface modification with U-treated poly(vinylferrocene). The effect of pH and temperature on the EL of ZnS Mn in aqueous and butyronitrile solutions upon reduction of per-oxydisulfate ion was also studied. EL of polycrystalline chemical vapor deposited (CVD) ZnS doped with Al, Cu-Al, and Mn was also observed with peaks at 430, 475, and 565 nm, respectively. High EL efficiency, comparable to that of singlecrystal ZnS, was found for the doped CVD polycrystalline ZnS. In all cases, the EL efficiency was about 0.2-0.3%. 

Many of the linear conjugated tricyclic systems have interesting fluorescence or other electrophysical properties. Bis-pyrazolepyridines such as compound 30 have been incorporated into polymers as fluorescent chromophores <1999JMC339>, and used in doped polymer matrices <1997JMC2323>. They are electroluminescent at 425 nm and photoluminescent at 427 and 430 nm in a poly(vinylcarbazole) matrix with a quantum efficiency of 0.8. 

Z. Peng, J. Zhang, and B. Xu, New poly(p-phenylene vinylene) derivatives exhibiting high photoluminescence quantum efficiencies, Macromolecules, 32 5162-5164, 1999. 

M. Ariu, D.G. Lidzey, M. Sims, A.J. Cadby, P.A. Lane, and D.D.C. Bradley, The effect of morphology on the temperature-dependent photoluminescence quantum efficiency of the conjugated polymer poly(9,9-dioctylfluorene), J. Phys. Condens. Matter, 14 9975-9986, 2002. 

C. Weder and M.S. Wrighton, Efficient solid-state photoluminescence in new poly(2,5-dialkoxy-/j-phenylene ethynyleness, Macromolecules, 29 5157-5165, 1996. 

Gu Z, Bao Y-J, Zhang Y, Wang M, Shen Q-D (2006) Anionic water-soluble poly(phenyle-nevinylene) alternating copolymer high-efficiency photoluminescence and dual electroluminescence. Macromolecules 39 3125-3131... 

Copolymers containing alternating l,4-bis(phenylethenyl)benzene, l,4-bis(phenylethenyl)-2,5-dimethoxybenzene or l,5-bis(phenylethenyl)naphthalene chromophores, and dibenzo-24-crown-8 spacers within the polymer backbone, best represented by 87, showed blue light emission in solution, and tunable photoluminescence and electroluminescence depending on the structure of the chromophore. Blends of these copolymers with a small amount of poly(ethylene oxide), and lithium salt as active layers, form efficient light-emitting electrochemical cells <2003JMC800>. 

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