Photoluminescence stability

Li et al. studied the thermal dehydration of boronic acids (Fig. 9.23(a), [54]). Crosslinking considerably improved the photoluminescence stability. Multilayer capabilities were demonstrated. 

Boukherroub R, Morin S, Wayner DDM, Lockwood DJ (2000b) Thermal route for chemieal modification and photoluminescence stabilization of porous sihcon. Phys Status Solidi A-Appl Res 182 117-121... 

Remarkably enough, 47 is a blue dye with a high photoluminescence quantum yield and, nevertheless, a high photochemical stability. Figure 7 shows the spectra of the different rylenetetracarboxdii-mide oligomers. 

J.-I. Lee, G. Klaemer, and R.D. Miller, Oxidative stability and its effect on the photoluminescence of poly(fluorene) derivatives end group effects, Chem. Mater., 11 1083-1088, 1999. 

We also examined the preservation stability of the photoimmobilized antibodies. Although the reactivity of the antibodies dropped away over a period of 10 days when they were stored at room temperature, it was maintained for about 2 months when stored at 4°C. This result is acceptable in terms of commercial viability, though further increase in stability would be preferable. We next examined the sensitivity for the immunochips. An immu-nochip usually has a two-dimensional surface, so the detection limit for antigens can be estimated from the amount of immobilized antibodies that are present. It was difficult to increase the sensitivity of a detection system which uses a photoluminescence probe. However, we succeeded in obtaining higher sensitivity for an immunochip in which we adopted a chemiluminescence detection system using an enzyme reaction. 

Depending on the kind of synthesis, these quantum dots can be prepared or size separated into batches covering almost the entire visible spectral range from 400 to 750 nm with, in part, high photoluminescence quantum efficiencies (some stable in air [106], others not [107]). Weller et al. reported on a very efficient synthesis for hydrophilic, thiol-capped CdTe quantum dots [108,109], which can be transformed to lipophilic, alkanethiol-stabilized CdTe quantum dots using a place exchange reaction similar to that for metal nanoparticles described above [110]. A related strategy has also been successfully employed to produce hydrophobic or otherwise functionalized CdS [111] or CdSe quantum dots [112] (Fig. 1). 

The =Si-0-0 radicals stabilized on the solid surface are stable up to the temperature 650 K. During further temperature increase their dissociation starts accompanied by a quantitative formation of the =Si-0 radicals and appearance of molecular oxygen in a gas phase. The formation of oxy radicals during this process was controlled by two methods (1) the EPR method (the appearance of a broad anisotropic signal, see Figure 7.16a (2) the photoluminescence method (the growth of characteristic red photoluminescence (/imax = 1.95 eV) under UV irradiation of the sample). Thus, a thermal decomposition of peroxy radicals proceeds according to the scheme ... 

The mechanistic route followed for the reduction process was different in the case of Ag/mycelium and Ag/media. In media, glucose was found mainly responsible for the reduction whereas in the case of mycelium, it was mainly the S-H group responsible for the same. The photoluminescence spectrum of these protein-stabilized silver nanoparticles also showed much enhanced fluorescence emission intensity. 

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