Ye Kaiqi, Wang Jia, Sun Hui, Liu Yu, Mu Zhongcheng, Li Fei, Jiang Shimei, Zhang Jingying, Zhang Hongxing, Wang Yue, Che Chi-Ming
Key Laboratory for Supramolecular Structure and Materials of Ministry of Education, College of Chemistry, Jilin University, Changchun 130012, People's Republic of China.
J Phys Chem B. 2005 Apr 28;109(16):8008-16. doi: 10.1021/jp0444767.
The synthesis and single-crystal X-ray structures of two quinacridone derivatives, N,N'-di(n-butyl)quinacridone (1) and N,N'-di(n-butyl)-1,3,8,10-tetramethylquinacridone (2), are reported, and the 1H NMR, absorption, photoluminescent (PL), and electroluminescent (EL) characteristics are presented. Both these crystal structures are characterized by intermolecular pi...pi and hydrogen bonding interactions. The intermolecular pi...pi interactions lead to the formation of molecular columns in the solids of 1 and 2, and the interplanar contact distances between two adjacent molecules are 3.48 and 3.55 angstroms, respectively. Crystals of 1 display shorter intermolecular pi...pi contacts and higher density than 2. These results suggest that tighter intermolecular interactions exist in 1. The 1H NMR, absorption, and PL spectra of 1 and 2 in solutions exhibit concentration-dependent properties. The PL quantum yields of 1 in solutions decrease more quickly with the increase of concentration compared to that of 2 in solutions. For solid thin films of Alq3:1 (Alq3 = tris(8-hydroxyquinolinato)aluminum), emission intensities dramatically decrease and obvious red shifts are observed when the dopant concentration is above 4.2%, while for films of Alq3:2, a similar phenomenon occurs when the concentration is above 6.7%. EL devices with Alq3:1 as emitting layer only show high efficiencies (20.3-14.5 cd/A) within the narrow dopant concentration range of 0.5-1.0%. In contrast, high efficiencies (21.5-12.0 cd/A) are achieved for a wider dopant concentration range of 0.5-5.0% when Alq3:2 films are employed as emitting layer. The different PL and EL concentration-dependent properties of the solid thin films Alq3:1 and Alq3:2 are attributed to their different molecular packing characteristics in the solid state.
报道了两种喹吖啶酮衍生物N,N'-二正丁基喹吖啶酮（1）和N,N'-二正丁基-1,3,8,10-四甲基喹吖啶酮（2）的合成及单晶X射线结构，并给出了它们的1H NMR、吸收、光致发光（PL）和电致发光（EL）特性。这两种晶体结构均以分子间的π…π和氢键相互作用为特征。分子间的π…π相互作用导致在1和2的固体中形成分子柱，两个相邻分子之间的面间距分别为3.48和3.55埃。1的晶体显示出比2更短的分子间π…π接触和更高的密度。这些结果表明1中存在更紧密的分子间相互作用。1和2在溶液中的1H NMR、吸收和PL光谱表现出浓度依赖性。与2在溶液中的情况相比，1在溶液中的PL量子产率随浓度增加下降得更快。对于Alq3:1（Alq3 = 三（8-羟基喹啉）铝）的固体薄膜，当掺杂剂浓度高于4.2%时，发射强度显著降低并观察到明显的红移，而对于Alq3:2薄膜，当浓度高于6.7%时会出现类似现象。仅以Alq3:1作为发光层的EL器件仅在0.5 - 1.0%的窄掺杂剂浓度范围内显示出高效率（20.3 - 14.5 cd/A）。相反，当采用Alq3:2薄膜作为发光层时，在0.5 - 5.0%的更宽掺杂剂浓度范围内可实现高效率（21.5 - 12.0 cd/A）。固体薄膜Alq3:1和Alq3:2不同的PL和EL浓度依赖性特性归因于它们在固态下不同的分子堆积特征。
