Ryu Gweon Young, Lee Sang Gu, Shin Sung Eui, Park Jong Jin, Park Seungho, Shin Dong Myung
Department of Mechanical and System Design, Hongik University, Seoul 121-791, Korea.
J Nanosci Nanotechnol. 2010 Oct;10(10):6805-10. doi: 10.1166/jnn.2010.2962.
Typical small red light-emitting molecules for organic light emitting diodes (OLEDs) were highly susceptible to fluorescence concentration quenching in solid state. Red fluorophores, (2Z, 2'Z)-3, 3'-[4,4"-bis(dimethylamino)-1,1':4',1"-terphenyl-29',5'-diyl]bis(2-phenylacrylonitrile) (ABCV-P), (2E, 2'E)-3,3'-[4,4"-bis(dimethylamino)-1,1':4',1"-terphenyl-2',5'-diyl]bis[2-(2-thienyl)acrylonitrile] (ABCV-Th) and (2Z, 2'Z)-3,3'-[4,4"-bis(dimethylamino)-1,1':4',1"-terphenyl-2',5'-diyl]bis[2-(2-naphthyl)acrylonitrile] (ABCV-Np), capable of preventing fluorescence concentration quenching were designed and synthesized. These compounds have intramolecular charge transfer (ICT) properties which were estimated by measurement of UV-Visible absorption and photoluminescence (PL) emission spectra with variation of solvent polarity (n-Hexane/Chloroform = 99/1, 1/1; Chloroform; Methylene chloride). The magnitude of ICT for ABCV-Th was measured to be the largest and that for ABCV-Np was slightly larger compared to that for ABCV-P. The magnitude of ICT resulted in a shift of peak wavelength of PL emission. Therefore, this result well supported substituent effect on the color change of PL emission. The peak wavelengths of photoluminescence for ABCV-P, ABCV-Np and ABCV-Th were observed to be 607.5, 611.5 and 617.5 nm, respectively, and those of EL spectra were measured to be 612.5, 619.5, 621.0 nm, respectively. The emission maxima of PL and EL spectra for these red fluorescent compounds were well correlated with substituent effect on ICT for them.
用于有机发光二极管（OLED）的典型红色小分子发光体在固态时极易发生荧光浓度猝灭。设计并合成了能够防止荧光浓度猝灭的红色荧光团，即(2Z, 2'Z)-3, 3'-[4,4"-双（二甲氨基）-1,1':4',1"-三联苯-29',5'-二基]双（2-苯基丙烯腈）（ABCV-P）、(2E, 2'E)-3,3'-[4,4"-双（二甲氨基）-1,1':4',1"-三联苯-2',5'-二基]双[2-(2-噻吩基)丙烯腈]（ABCV-Th）和(2Z, 2'Z)-3,3'-[4,4"-双（二甲氨基）-1,1':4',1"-三联苯-2',5'-二基]双[2-(2-萘基)丙烯腈]（ABCV-Np）。通过测量紫外可见吸收光谱和光致发光（PL）发射光谱随溶剂极性（正己烷/氯仿 = 99/1、1/1；氯仿；二氯甲烷）的变化，对这些化合物的分子内电荷转移（ICT）性质进行了评估。测得ABCV-Th的ICT幅度最大，ABCV-Np的ICT幅度比ABCV-P略大。ICT幅度导致了PL发射峰波长的移动。因此，该结果很好地支持了取代基对PL发射颜色变化的影响。观察到ABCV-P、ABCV-Np和ABCV-Th的光致发光峰波长分别为607.5、611.5和617.5 nm，电致发光光谱的峰波长分别为612.5、619.5、621.0 nm。这些红色荧光化合物的PL和EL光谱发射最大值与它们的ICT取代基效应有很好的相关性。
