Orange emitters

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. 

White emission can also be achieved by directly combining a blue emitter and an orange-red emitter as codopants. The combination of blue and orange-red emission generates white emission. 

For over 50 years the phosphors of choice for luminescent lighting have been based on activated calcium halophosphates, Ca3(PO )3X (where X = F, Cl), the usual activators being Sb " and Mn ". When Sb " is used as the dopant the phosphor is a very efficient blue emitter under 254 nm excitation, whilst Mn shows an orange... 

The SrCl molecule emits a series of bands in the 620-640 manometer region - the "deep red" portion of the visible spectrum. Other peaks are observed. Strontium monohydroxide, SrOH, is another substantial emitter in the red and orange-red regions [1,11]. The emission spectmm of a red flare is shown in Figure 7.1. 

Duan, J.-P. Sun, P.-P. Cheng, C.-H. (2003). New Iridium Complexes as Highly Efficient Orange-Red Emitters in Organic Light-Emitting Diodes. Advanced Materials, Vol. 15, pp. 224-228. 

The family of cyanine (Cy) fluorochromes includes orange -and red-emitters (13, 14). The red-emitting cyanine 3.18, for example, which was shown to give a significantly brighter image than TRITC, lissamine rhodamine, Texas Red, or fluorescein under specific conditions of microscopy (7), provides a useful alternative to the rhodamines. Other useful substitutes for rhodamines include the Cy3 and 3.5, BODIPY TMR and TR, and... 

HOMO-LUMO gap of CN-PPV XIII is about 2.1 eV (590 nm) and two-layer electroluminescent devices made of ITO/PPV (as a hole transporting layer)/CN-PPV (as emitter)/Al or Ca, exhibit a red electroluminescence with a peak at 710 nm and a i7ext) of about 1 % [31]. The same two-layer configuration devices based on MEH-CN-PPV XIV exhibit a red-orange electroluminescence peaking at ca. 600 nm, a rjext = 2.5%, a luminous effiency of 2.5 lm/W, and a luminance of 1000 cd/m2 at 6 V [166,189]. The blue-shifted emission of MEH-CN-PPV in comparison with that of CN-PPV has been ascribed to a steric effect of the branched ethylhexyl side-chain, which induced a slight twisting of the polymer backbone. 

Duan, J.-R, Sun, P.-R, and Cheng, C.-H. 2003. New iridium complexes as highly efficient orange-red emitters in organic light-emitting diodes. Adv. Mater. 15 224. 

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