Synthesis, Characterization And Properties Of Spiro - Fluorene Organic Small Molecule Photoelectric Functional Materials

Because of three-dimensional structure, special electronic effect and excellent thermal stability, spirobiflurene compounds have become one of the research hotspots in the field of organic functional materials in recent years. It has been widely used in the field of organic photoelectric functional materials, such as organic light emitting devices (OLED), organic photovoltaic cells (OPV), organic thin film transistor (OTFT), nonlinear optical materials, etc.Currently, most of the spirobifluorene compounds reported in the literatures are the "left-right" asymmetric spirobifluorene compounds. Due to the difficulty in synthesis, there are few research about the "top-down" asymmetric spirobifluorene compounds and other asymmetric structures. In this paper, a series of "top-down" asymmetric and other asymmetric spirobifluorene compounds were synthesized, and the related photoelectric properties was studied. In addition, the influence on three-dimensional structure of9,9’-spirobifluorene to the thermal stability of small organic molecule functional materials was also studied. Some further study about the influence of spiroconjugation effect in photoelectric properties of small organic molecule functional materials were carried out as well.The work of this paper is mainly divided into the following three parts:1. TM-1which is a kind of "top-down" asymmetric spirobiflourene compounds was synthesized. Its uv-vis absorption spectrum, fluorescence emission spectrum under the environment of pH dependent is also studied. It was proved that TM-1has excellent performance of fluorescent probe under the environment in interval pH5-7. The possible mechanism was also proposed.2. SPF-D2which is a kind of "top-down" asymmetric spirobifluorene compounds was synthesized, showing good thermal stability (Tg:266℃,Td:466℃). It was verified that using9,9’-spirobifluorene structure as the conjugated π bridge could greatly improve the thermal stability of compounds. Its spectral properties and electrochemical properties were studied, and the performance in electroluminescent was also studied by making light-emitting devices which was used SPF-D2. The experimental results show that SPF-D2could be used as both hole-transporting material and luminescent material. The light-emitting device could emit pure blue light (CIE coordinate0.15,0.10). And it has good performance in electroluminescent (starting voltage:3.2V, maximum brightness:3013cd/m2, current efficiency:1.71cd/A, energy efficiency:1.79lm/W).3. SPF-D1, SPF-D1A1, SPF-D2A1and other reference compounds were synthesized. The two-photon absorption cross section of SPF-D2, SPF-D1A1, SPF-D2A1were measured by Z-scanning, and the value was162.5GM,268.3GM,635.4GM, respectively. Its optical properties, electrochemical properties and two-photon absorption properties were also studied. It was found that substituent and the spiroconjugation effect has the influence to the performance of two-photon absorption of spirobifluorene compounds.