Comparison of light sources for use in a retinal scanning display

(TPD/AIQ,) (0.6%). Also for blue-emitting device with DPVBi as an emission layer, b-DPQX works as electron transporter and the efficiency was enhanced up to 0.35% from the value of 0.2% when AIQ, was used as an electron transport layer. When 0.5 wt. % of quinacridone (3) was doped in the AIQ, layer of a two-layer device with bis(di-tolylaminopheny1)cyclohexane (TAPC) as a hole transporter, its external effciency was enhanced to 2.0% from 0.8% of an undoped AlQ, device. Maximum luminance was up to 10,000 cdlm' without cooling. We also synthesized a new soluble quinacridone derivative showing strong fluorescence in solution. Its LED properties as a dopant will be discussed. In conclusion, we developed a quinoxaline derivative with good performance as an electron transporter in blue and green organic LED devices. These compounds may yield higher performance by optimizing their combination with emission layer. This work was supported by ONR through the MVRI Center CAMP. 1. N. Tessler, G. J. Denton, R. H. Friend, Nature 382,695 (1996). 2. F. Hide, M. A. Diaz-Garcia, B. J. Schwartz, M. R. Anderson, Q. Pei, A. Heeger, Science 273, 1833 (1996). S. Saito, T. Tsutsui, M. Era, N. Takada, C. Adachi, Y. Hamada, T. Wakimoto, Proc. SPIE 1910,212 (1993). T. Yamamoto, T. Inoue, T. Kanbara, Jpn. J. Appl. Phys. pt. 2,33, L250 (1994). 3.