Owing to their merits like solid-state self-emission, wide viewing angle, facile color tunability and processability, organic light-emitting devices (OLEDs) have been considered as quite competitive candidates in flat-panel display applications. At present, the performance of red OLEDs with good chromaticity is still unsatisfactory. Hence, it is highly demanded to exploit novel high performance standard-red electroluminescent (EL) materials. 1,8-Naphthalimide is a widely-used electron-accepting subunit for constructing high performance green and yellow D-A-structured EL materials, however, quite limited success has been achieved in terms of high performance orange and red ones.1-3 In this study, we designed and synthesized three red-emissive 1,8-naphthalimide derivatives bearing D-π-A skeleton, and the neat films of those compounds showed emission peaks in 656-679nm. When used as doping guest compound, one of them exhibits saturated red emission and moderate efficiency in a heavily blended film (14 wt%) with a host1 reported by our group recently. Further TGA characterization results indicated that this compound displays good thermal-stability. Using this compound as dopant, a standard-red device was obtained at doping level of 14 wt% with its EL emission peak located at 654 nm. The Commission Internationale de L’Eclairage (CIE) coordinates, maximum external quantum efficiency (EQE) and maximum current efficiency of this OLED are (0.67,0.32), 1.78% and 0.68 cd A-1, respectively. All these preliminary results indicated that through rational molecular design, 1,8-naphthalimide derivatives could act as promising standard-red light-emitting materials in OLED applications.
Acknowledgement We acknowledge National Natural Science Foundation of China (Project Nos. 21372168 and 21432005) for financial support.
References
1. J. Zhou, P. Chen, X. Wang, Y. Wang, F. Li, M. Yang, Y. Huang, J. Yu, Z. Lu, Chem. Commun., 2014, 50, 7586-7589
2. J. Liu, Y. Li, Y. Wang, H. Sun, Z. Lu, H. Wu, J. Peng, Y. Huang, Opt. Mater., 2012, 34, 1535-1542
3.J. Liu, Y. Wang, G. Lei, J. Peng, Y. Huang, C. Yong, M. Xie, X. Pu, Z. Lu, J. Mater. Chem., 2009, 19, 7753-7758
Corresponding author’s Email: luzhiyun@scu.edu.cn