The Optoelectronic Characteristic Study Of Neutral Conjugated Polymers/LDHs Self-Assembly Systems

Conjugated polymer optoelectronic materials, compared with inorganic materials such as inorganic semiconductor, shows significant advantages,for example, light, flexible, solution-processed. Especially,the photoelectric properties can be controlled by simple chemical modification. This dominant advantages make it important application in organic/polymer photoelectric device, such as Light-Emitting Diode (LED), photovoltaic cells, field-effect transistor (FET), information storage, and biological and chemical sensors. The neutral conjugated polymers we described in this paper means these conjugated polymers which are water-insoluble. And it’s side chain does not contain any hydrolyzable functional groups or high electronegative atom,such as N, O, S.That is,it is totally different from the polyelectrolytes. We developed the ayer-by-layer self-assembly method and assembled Layered double hydroxides (LDHs) with neutral conjugated polymers or neutral composite guest to form a composite thin film. And the optical property,structure and morphology of the film were characterized. The fluorescence spectra of the (PFH-Ec/LDH)n film shows that the (PFH-Ec/LDH)n film can act as a fluorescence chemosensor to specifically recognize precious metal ions,such as PdⅠ,PtⅠ,PtⅣ,AuⅢ ion and Pd nanoparticles. We further studied the relationships between the fluorescence intensity of (PFH-Ec/LDH)n film and the concentration of PdⅡ. Combined with experimental data, the mechanism of fluorescence quenching is explored. The research on (PCBM-CP/LDH)n film shows that The composite films can be applied to organic solar cells.The main work is as follows:1、In this paper,we successfully assembled Layered double hydroxides (LDHs) with different neutral conjugated polymers or neutral composite guest(neutral conjugated polymers containing PCBM),and the different (CP-LDH)n or (PCBM-CP/LDH)n thin film formed are uniform and orderly. This paper, based on the previous research, developed a layer-by-layer self-assembly(LBL) method whose driving force,we deduce, is van der Waals force or novel hydrogen bond,which is completely different from the LBL based on electrostatic force or the conventional hydrogen bond. It is generally believed that LDHs can only assemble with anion. But this method push the boundaries and expand the application scope of inorganic supramolecular material. This self-assembly method may be applicable to all the above neutral conjugated polymers and the neutral small molecule-neutral conjugated polymers binary system we described.2 s By the method above,the (PFH-Ec/LDH)n film is prepared, as a fluorescence chemosensor, not only can specifically recognize precious metal ions,such as Pd Ⅱ,Pt Ⅱ,Pt Ⅳ,Au Ⅲ ion,but also show strong fluorescence response to Pd nanoparticles with a extremely high Stern-Volmer quenching constant of more than 3×108 M-1,which is much larger than the general quenching agent.For PdⅡ,the Stern-Volmer quenching constant Ksv is 5000 M-1,and within the range from 10-5 M to 10-2 M, there is a linear relationship between the fluorescence intensity and the negative logarithm of the concentration of PdⅡ, which can be applied to determine the concentration of PdⅡ. Based on the experimental fact,the mechanism of fluorescence sensing was reasoned. This chapter provides a new type of composite film,which can be applied to the detection of precious metals ions and nanoparticles.As to Pd nanoparticles, super fluorescence quenching occurred and the detection is very sensitive.3、In a similar way,we prepared the neutral small molecule-neutral conjugated polymers/LDH film,for example, (PCBM-P3HT/LDH)n, (PCBM-PFPC/LDH)n.The study of (PCBM-CP/LDH)n film demonstate that once the neutral conjugated polymers and PCBM were intercalated into the layers of LDHs, the two-dimensional fluorescence quenching generated. The two-dimensional photo-induced electron-transfer between the layers of LDHs shows the potential applications of (PCBM-CP/LDH)n film in organic solar cell. And the successful fabrication of (PCBM-CP/LDH)n film makes full preparation for the applications of LDHs in active layer of OSCs.