基于嵌段共聚物的发蓝绿光聚合物发光电池的制备和表征

Fabrication and Characterization of Blue-Green Light-Emission LEC Based on a Block Copolymer with DMSN and TEO Segments

基于一种嵌段共聚物DMSN TEO制备出了发蓝绿光的聚合物发光电池 (LEC) ,并对其光谱性质、电致发光特性和界面性质进行了表征。LEC结构为ITO/DMSN TEO +PEO(LiCF3 SO3 ) /Al,起亮电压为 2 5V ,最大电致发光效率为 4 2cd/A ,最大流明效率 4 7lm/W ,响应时间小于 5s。交流阻抗谱研究这种LEC的界面性质表明 。

The polymer light emitting electrochemical cell (LEC) provides a novel approach for light emission from the conjugated luminescent polymers. However, a phase separation occurs intrinsically in the electroluminescent (EL) device due to the addition of polymer electrolyte. To reduce or eliminate the phase separation, a novel block copolymer was presented as the luminescent polymer for the fabrication of the LEC in this work. The block copolymer is composed of the rigid segments, 1,5 di(3,5 dimethoxystyrylene)naphthalene (DMSN) and the flexible segments, tri(ethylene oxide) (TEO). Optical and electrochemical properties of DMSN TEO were studied firstly by the absorption, photoluminescence spectra and cyclic voltammetry measurements, and the data show that this copolymer is a typical p type material with a blue emission in solution. The polymer LEC was fabricated successfully by sandwiching a blend film composed of DMSN TEO, PEO and lithium triflate between an ITO and an Al electrode, and characterized by current voltage luminance characteristics, d.c. response and a.c. impedance measurements. Efficient blue green light emission of the LEC was demonstrated with an onset voltage at 2 5V and the maximum EL efficiency of ～4 2cd/A at 2 8V. The response time of the LEC is less than 5s. All the results suggest that an improved morphology of the blend film is achieved in the LEC due to the presence of TEO segments in the copolymer. The a.c. impedance data indicate the electrochemical doping mechanism of the LEC.