摘要
通过溶胶反应在乙醇溶液中合成了60nm的SiO2纳米粒子,将其与聚乙烯咔唑(PVK)共混,得到了不同质量分数的PVK/SiO2复合体系。利用荧光光谱、吸收光谱,研究了PVK/SiO2复合体系的荧光效应,光致发光的研究表明在PVK与SiO2纳米粒子之间存在界面能量传递过程,这种能量传递的必要条件是PVK的发射谱与SiO2纳米粒子的吸收谱有重叠。以上研究表明PVK/SiO2复合体系存在较强的界面效应,是研究有机与无机纳米体系界面效应的良好模型。
Poly(9vinylcarbazole) (PVK) is a typical holetransporting polymer and is often used as a host in electroluminescence devices.In this paper, Frster energy transfer from organic molecules (PVK) to inorganic nanoparticles ( SiO2) was discussed. SiO2 nanoparticles, which are confirmed to be 60nm using transmission electron microscope (TEM), have been synthesized by sol. The structure scheme of poly (9vinylcarbazole) (PVK) molecule is shown firstly. The emission of luminescence is the result from π*π transition of π electrons. Photoluminescence (PL) spectra of the PVK/SiO2 composite film on Si substrates were employed to study the interface effect. In the PL spectra of PVK molecules, three obvious peaks (417, 458, 495nm ) can been seen. The emission of 417nm comes from free exciton. The emission of 458nm comes from bound exciton. And the emission around 495nm is correlated to surface defect states. The intensity of shortwavelength emission (about 400nm) is higher than that of visible luminescence (about 495nm). Two luminescence peaks can be observed in the PL spectra of 60nm SiO2 nanoparticles. In contrast to the PL spectra of PVK molecules, the luminescence intensity about 495nm is higher than that about 400nm in SiO2 nanoparticles PL spectra. Furthermore, UV/Visible absorption spectroscopy of 60nm SiO2 nanoparticles was measured. The spectrum indicates that the scale of absorption is wide enough from 200nm to 500nm. The ratio of PVK to SiO2 in the composite was increased orderly in weight. In the PL spectra of different concentration composite films, we found that Frster energy transfer occurred between PVK and SiO2 nanoparticles. Overlap is observed between the UVVisible absorption spectrum of the SiO2 nanoparticles and the emission spectrum of PVK molecules. We suggest that this overlap is the necessary condition of Frster energy transfer. Further investigation indicates that 40% (the content of PVK in composite in weight) is regarded as an optimized content for Frster energy transfer from PVK molecules to SiO2 nanoparticles. The reason maybe is the surfaces of SiO2 nanoparticles are modified successfully and the disperse of SiO2 nanoparticles is unified in this concentration.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2002年第6期590-594,共5页
Chinese Journal of Luminescence
基金
国家自然科学基金资助项目(19974048)
