Preparation, Properties And Applications Of Nanomaterials Based On Organic Optoelectronic Molecules

Much attention has been paid to nanomaterials based on small organic molecules due to their diversity structure and unique properties. Nanomaterials based on small organic molecules are promising materials in different fields. Unlike their inorganic and macromolecular counterparts, nanomaterials based on small organic molecules have been the subject of research interest only in recent years. The research on nano organic materials is still in its infancy, and much remains to be done. Due to their structural diversity and complexity of organic molecules, individual differences become prominent. For example, the theory applied to this class of compounds may not be fit for other types of compounds. However, the challenge and opportunity are coexsisted in studing the nanomaterials based on small organic molecules, because of their special optical properties and structural diversity and complexity of the organic materials.∧-shaped twisted configuration of TB analogues are not easy to formπ-πclose stacking, therefore, such kind of compounds may be good candidates for luminescent application since less fluorescence quenching existed in their solid state. Based on this idea, a new∧-shaped TB based host red light materials DMCEM is designed, synthesized and its photophysical properties are examined in detail. This compound exhibits strong red fluorescence in the solution and solid states. Nanocrystals of DMCEM with well-defined spherical morphology are prepared by a simple reprecipitation method. We find that the DMCEM naoparticles possess special size dependence in their optical properties. Such an evolution of the optical properties of the fluorescent organic nanoparticles as a function of particle size provide another strategy to tune the color of the luminescent materials only by the variation of the particle size, which holds promise for application in optoelectronic devices.Two∧-shaped TB analogues TBFB-BP and TBFB-TPA containingπ-conjugated biphenyl and triphenylamine substituted fluorene groups were selected as model compounds and the stable suspensions of TBFB-BP and TBFB-TPA nanoparticles of different sizes were prepared through the reprecipitation protocol leading to highly monodisperse nanocrystals with well-defined morphology. A strong size dependence of continuous bathochromic absorption and significant enhanced emission were observed with the increase of the TBFB-BP particle size, which may be attributed to the increased rigidification of the crystal lattice and the associated decrease of vibrational relaxation of this compound. But for more polar TBFB-TPA molecule, the emission spectra exhibit obvious hypsochromic shift due to the effect of solvate effects. This is the first report on the size-dependent optical properties of new fluorescent A-shaped organic nanoparticles and the influence of molecular polarity on the size-dependent optical properties. Such an optical size effects observed in the TBFB-BP and TBFB-TPA nanoparticles may provide an alternate approach for achieving color modulation for electroluminescent materials.Doping based on fluorescence resonance energy transfer has been widely used in electroluminescent (EL) devices because the luminescence efficiency and emission colors can be improved by such method. BFB-TPA and red light AIE materials 1DPAFO,2DPAFO are selected as model compounds and the stable suspensions of TBFB-TPA/1DPAFO and TBFB-TPA/2DPAFO hybrid nanoparticles are prepared. And their photophysical properties were examined in detail. We found that fluorescence emission from the prepared nanoparticles can be tuned simply by changing the content of 1DPAFO,2DPAFO in the hybrid nanoparticles respectively.There is a tendency to combine the nanomaterials with biomolecule. But the vast majority of previous studies are focused on inorganic and metal nanomaterials, very few organic bio-nanomaterials are prepared. In this paper, the lysozyme has been used in the synthesis of TKPVB nanoparticles to design bio-nanomaterials whose photophysical properties was affected by the interaction of TKPVB nanoparticles with lysozyme. The morphology and photophysical properties of TKPVB nanoparticles were studied in lysozyme or lysozyme-free solution. Well-defined TKPVB nanowires were formed in both solutions but with shorter length in the presence of lysozyme due to the hydrophobic interaction of lysozyme with TKPVB molecules on the surface. Lysozyme prevent the further association of TKPVB molecules and slow down the process of self-assembly at the initial stage, which maybe also responsible for the more obvious bathochromically shifted J-aggregate absorption bands and emission peak together with recovered fluorescence intensity observed in the lysozyme solution. With increasing the concentration of TKPVB nanoparticles, the continuous blue shifted of tryptophan emission in TKPVB/lysozyme bioconjugate suggest conformational changes for lysozyme occurred at tertiary structure levels. The fluorescence properties of the TKPVB/lysozyme bioconjugate can be controlled by pH changes. Dual-colored emission was observed by exposing the bioconjugate under neutral and acidic environments.ξ-potential measurements indicate electrostatic interaction play an important role between the two components. The bioconjugate might find great potential in probing the pH in complicated environments, and have the potential to be used in bioanalysis and the in vivo transfer of small molecules. The research on the fluorescent organic nanoparticles and its bioconjugate will expand their applications in the chemical and biological fields.In summary, our work focuses on the organic nanomaterials. A series of organic nanoparticls has been prepared and special size dependent optical properties are found. Bioconjugated nanomaterials have been prepared and their application in biological fields is explored.