Synthesis And Optical Properties Investigation Of Aromatic Group Silane Derivatives

In this paper, diphenylfluoranthene and three novel silicon-cored diphenylfluoranthene derivatives were synthesized by convenient ways. The systematic properties and structures of four compounds were investigated and discussed. In contrast to diphenylfluoranthene, these silicone-cored diphenylfluoranthene derivatives show higher thermal stabilities and glass transition temperatures. These silicon-cored compounds with excellent thermal properties will be suitable to apply in organic opticelectric devices. The absorption spectra, fluorescence emission spectra and cyclic voltammetry (CV) spectra of four compounds in dilute solution were tested and it was found that they exhibited similar spectra in dilute solution, indicating that the silicon-cored structures did not change the conjugation length of diphenylfluoranthene and well retained the nature properties of diphenylfluoranthene. However, the silicon-cored derivatives exhibited better fluorescent emission properties in solid state than diphenylfluoranthene because these silicone-cored derivates exhibited weaker π-π interactions among molecules. Furthermore, it was found that the substituent groups on Si atom have great influence on the fluorescent emission properties in solid state. The silicon-cored methylphenyl diphenylfluoranthene derivative exhibited better fluorescence emission than dimethyl and diphenyl silicon-cored derivatives. And it showed similar fluorescence emission spectra in both solution and solid state which may be the most appreciate candidate for efficient solid-state emitter.A silicon-cored fluoranthene derivative named bis (7,10-diphenyl-fluoranthene) methylphenylsilane (BFMPS) was designed and synthesized as the donor. A perylene end-capped polydimethylsiloxane (PECP) with high orange emission, good solubility and film forming ability was synthesized and used as the acceptor for preparing the blending systems. A series of tunable luminescence was obtained by controlling the donor/acceptor ratios. The absorption spectrum of PECP showed a good overlap with the luminescent emission spectrum of BFMPS from400nm to550nm. This overlapping indicated the possibility of energy transfer from BFMPS to PECP. Efficient energy transfer was detected in these unique blending systems, which were composed of small molecules and fluorescence macromolecules. Based on the energy transfer, the BFMPS/PECP blending system showed tunable fluorescence emission colors in both solution and thin films. In particular, pure white emission was obtained when the adequate blending ratio was adopted. Further characterizations and investigations were carried out to examine the energy transfer from donor to acceptor in both solution and solid thin films. Two different energy transfer mechanisms were deduced from the investigation of the ultraviolet absorption and luminescence spectra. Radiative energy transfer was dominant in solution while Foster resonant energy transfer was dominant in thin films.Based on the energy transfer mechanism between BFMPS and perylene tetracarboxylic acid bisimide, functional materials were prepared. N,N-dicyclohexyl-perylene-3,4,9,10-tetracarboxylic acid bisimide (CH-PTCDI), a PTCDI derived from simple modification, was selected as the acceptor for preparing energy transfer system. a series of organic composte BFMPS/CH-PTCDI nanoparticles with different CH-PTCDI content by reprecipitation were obtained. To our knowledge, it was the first report that the silicon-containing molecules were used in orgainc composite nanoparticles. The composite nanoparticles exhibited good stability and thermal properties. The fluorescence emission of the perylene bisimide dye can be efficiently enhanced in composite nanoparticles based on efficient Foster resonant energy transfer. The composite nanoparticles exhibited tunable emission colors from blue to red by changing the concentration of perylene bisimide dye. White-light emission with CIE coordinates (0.327,0.339) was obtained as a good candidate for applications in white optoelectronic devices.The materials with aggregation induced emission (AIE) were important in luminescenct materials because they could fundamentally solve the aggregation caused quenching of chromophore. In this paper, a novel AIE system based on dendritic bezene was reported. Tetraphenyl benzene and its two derivates were synthesized and their optical behaviors were partically investigated. All the three compounds exhibited aggregation induced emission enhancement (AIEE) properties at a low concentration. The AIEE mechnism was investigated and indue to restricted intramolecular rotation and unique molecular packing modes. However, this kind of dendritic benzene derivatives exhibited interesting optical properties with increased concentration which is different from common AIE molecules. Furthermore, a new phenonmenon that the silicon-cored structure could efficiently enhance emission intensity and adjust emission colors of dendritic benzene was found. The phenomenon was called "silicon-cored effect." This effect may give some guidance to the design of new luminescent materials with AIE properties.