Synthesis and Photophysical Properties of Pyrene-Based Multiply Conjugated Shaped Light-Emitting Architectures: Toward Efficient Organic-Light-Emitting Diodes

Since the pioneering works on the first double-layer thin-film Organic electroluminescence (EL) devices (OLEDs) by C. W. Tang and co-workers in the Kodak Company in 1987 (Tang  Vanslyke, 1987), OLEDs have attracted enormous attentions in the scientific community due to their high technological potential toward the next generation of full-color-flat-panel displays (Hung  Chen, 2002; Wu et al., 2005; Geffroy et al., 2006) and lighting applications (Duggal et al., 2007; So et al., 2008). In today’s developments of OLED technologies, the trends of organic EL devices are mainly focusing both on optimizations of EL structures and on developing new optoelectronic emitting materials. Obviously the key point of OLEDs development for fullcolor-flat display is to find out materials emitting pure colors of red, green and blue (RGB) with excellent emission efficiency and high stability. Numerous materials with brightness RGB emission have been designed and developed to meet the requirements toward the full-color displays. Among them, organic small molecules containing polycyclic aromatic hydrocarbons (PAHs) (e. g. naphthalene, anthracene, perylene, fluorene, carbazole, pyrene, etc.) are well known and are suitable for applications in OLEDs. Recently, naphthalene, anthracene, perylene, fluorene, carbazole, pyrene and their derivatives have been widely used as efficient electron-/hole-transporting materials or host emitting materials in OLED applications. In this chapter an overview is presented of the synthesis and photophysical properties of pyrenebased, multiply conjugated shaped, fluorescent light-emitting materials that have been disclosed in recent literatures, in which several pyrenes have been successfully used as efficient hole-/electron-transporting materials or host emitters or emitters in OLEDs, by which a series of pyrene-based, cruciform-shaped -conjugated blue-light-emitting architectures can be prepared with an emphasis on how synthetic design can contribute to the meeting of promising potential in OLEDs applications.