Yellow emitters

Fig. 4 Steady-state excitation and emission spectra for live distinct ssDNA encapsulated Ag clusters, (a) Blue emitters created in 5 -CCCTTTAACCCC-3, (b) green emitters created in 5 -CCCTCTTAACCC-3, (c) yellow emitters created in 5 -CCCTTAATCCCC-3, (d) red emitters created in 5 -CCTCCTTCCTCC-3, and (e) near-IR emitters created in 5 -CCCTAACTCCCC-3. (f) Pictures of emissive solutions in (a)-(d) [46]...

In order to enhance the device performance of PWLEDs, novel PWLEDs were developed through double doping of blue emitter (FIrpic) and yellow emitter (iridium complexes) (Fig. 7.5A) into PVK (host material) with the presence of electron transporting material l,3-bis[(4-tertbutylphenyl)-l,3,4-oxadiazolyl]phenylene (OXD-7) (Wu et al., 2009). The... 

EL experiments showed that the yellow-emitting LEDs prepared from LPPP 12 exhibit quite remarkable characteristics (single layer construction ITO/LPPP 12/Ca quantum efficiency ca. 1.0%, applied voltage 4-6 V 135]). These figures are in the range of the best values described hitherto for polymeric emitters in a single layer arrangement, for example, poly(pcira-phenylenevinylene) PPV and PPV derivatives. 

The optical properties can be tuned by variations of the chromophores (e.g. type of side-chains or length of chromophorc). The alkyl- and alkoxy-substituted polymers emit in the bluc-gnecn range of the visible spectrum with high photolu-inincsccncc quantum yields (0.4-0.8 in solution), while yellow or red emission is obtained by a further modification of the chemical structure of the chromophores. For example, cyano substitution on the vinylene moiety yields an orange emitter. 

Because luciferyl adenylate emitted a red chemiluminescence in the presence of base, coinciding with the red fluorescence of 5,5-dimethyloxylucferin, the keto-form monoanion Cl in its excited state is considered to be the emitter of the red light. Thus, the emitter of the yellow-green light is probably the enol-form dianion C2 in its excited state, provided that the enolization takes place within the life-time of the excited state. Although the evidence had not been conclusive, especially on the chemical structures of the light emitters that emit two different colors, the mechanism shown in Fig. 1.12 was widely believed and cited until about 1990. 

According to Branchini et al. (2004), luciferase modulates the emission color by controlling the resonance-based charge delocalization of the anionic keto-form of oxyluciferin in the excited state. They proposed the structure C5 as the yellow-green light emitter, and the structure C6 as the red light emitter. 

It should be pointed out that the structure C5 (yellow-green emitter) is identical to the structure Cl that was previously assigned to the red light emitter. 

Yellow and Red Dopants Phosphorescent Emitters Creating White Light Creating Polarized Light... 

The oxidizer s positive ion (cation) must not adversely affect the desired flame color. Sodium, for example, is an intense emitter of yellow light, and its presence can ruin attempts to generate red, green, and blue flames. 

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