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**Chapter 8** 

© 2012 Zarins et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2012 Zarins et al., licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**Synthesis and Physical Properties of Red** 

Elmars Zarins, Aivars Vembris, Valdis Kokars and Inta Muzikante

Additional information is available at the end of the chapter

emitting compounds have been introduced by us [28-32].

http://dx.doi.org/10.5772/53462

**1. Introduction** 

**Luminescent Glass Forming Pyranylidene and** 

**Isophorene Fragment Containing Derivatives** 

Low molecular mass organic compounds with internal charge transfer properties are widely adopted for organic photonics such as materials for the creation of molecular electronics elements, organic magnets, solar cells and organic light emitting diodes (OLEDs) for full display panels [1-3]. One of the most widely used red light-emitting materials contains pyranylidene (4*H*-pyran-4-ylidene) or isophorene (5,5-dimethylcyclohex-2-enylidene) fragments as backbone of the molecule (see Fig.1), which are conjugated in a system with electron acceptor and electron donor fragments [1,4-24]. In many cases the light-emitting layer from such commercially available compounds is prepared by thermal evaporation in vacuum [1-2, 25-27]. Some of them are used as dopants in a polymer matrix and spin-coated onto a hole transport layer from solution [1,12]. However the doping amount of luminescent compound is limited by self crystallization and photoluminescence quenching at higher concentrations which reduce the quantum efficiency of fabricated devices significantly [11- 12]. Therefore it is important to synthesize low molecular mass light-emitting organic compounds which do not crystallize and form thin amorphous solid films from volatile organic solvents. Such compounds, which can make a solid-state glassy structure prepared from solutions, could facilitate technological processes in the production of many devices in optoelectronics, for example, light emitting devices by low-cost deposition such as wet casting methods and easier light-emitting material synthesis. Some of these red light-

In this chapter we present complete synthesis, thermal, optical, photoelectrical and glass forming properties of new organic glass-forming pyranylidene and isophorene fragment containing derivatives with bulky trityloxy groups in their molecules. The optical properties, both in solution and solid state, are compared. The dependance of
