Synthesis And Properties Of New Single Polymer With Linearly Polarized White Fluorescence

Single polymer linearly polarized white-light-emitting diodes are self-luminous, which can replace the background light source, polarizers, as well as liquid crystal cell of traditional liquid crystal displays, but also to greatly reduce the light loss, simplify the device structure, improve the brightness and viewing angle of display. Based on characteristics of liquid crystals and conjugated polymer, two series of five liquid crystalline conjugated polymers had been designed and synthesised. The polymer structure, relative molecular weight, liquid crystal properties and optical properties were characterized.1. According to optical theory, blue and yellow complementary colors can give white light when mixed with various compositions. However, different colors light-emitting materials is a large difference, and the device prepared by this way is prone to phase separation to affect the device stability. This problem can be solved by using a single polymer with white-light-emitting which synthesized by connecting the blue, yellow chromophore to the same polymer. The polymer with linearly polarized white light-emitting can be obtained if the polymer is in the orientation of the external force. Poly(p-phenylene)s is a good blue light-emitting materials, and poly(p-phenylene vinylene)s is a fine yellow light-emitting materials. In this paper, The novel liquid crystalline cross-conjugated (p-phenylene)s-poly-(p-phenylenevinylene)s hybrids were synthesized through Gilch polymerization in order to develop a kind of the polymer available for linearly polarized white-light-emitting from single chain. The P1main chain had been aligned by the virtue of orientation of side chain on the surface of rubbed polyimide and the cross-conjugated structure between mesogenic units of side chain and the polymer main chain also been destroyed. The alignment of the polymer main chain with yellow light emission was accompanied with orientation of the LC side chains with blue light emission and gave rise to a notable linearly polarized white fluorescence. The dichroic ratio (R) is3.2. Small organic molecules can easily form aggregation morphology (excimers, exciplexes, or aggregates) in the solid state. The blue emission materials with yellow emission of aggregation morphology can give white emission when the aggregation extent is large. Yellow emission come from the same blue emission materials can be simplified synthetic steps and can reduce the problem of the color changes caused by aging at different speeds due to the different structure of the materials, improve the life of the device. Such a method is introduced into the system of liquid crystal conjugated polymer, in order to achieve the goal of the preparation of a single polymer with linearly polarized white light emitting. Polyfluorenes have good planarity and high quantum efficiency, which are easy to form the aggregation morphology and blue emission materials. In this paper, the polyfluorene derivatives with different carapace densities of side group have been synthesized by Yamamoto and Suzuki metal coupling reaction. To drop the P5into the orientation microgroove of aligned polyimide annealed film, some part of the polymer main chain reverses to form spiral structure, showing blue emission, meanwhile, the other part of the polymer main chain form excimers, showing yellow emission, which was given rise to a notable linearly polarized white fluorescence. The dichroic ratio is2.4.