Blue top-emitting organic light-emitting devices using Alq₃ as phase shift adjustment layer

Abstract

Blue top-emitting organic light-emitting devices (TEOLEDs) are demonstrated by employing Alq₃ as phase shift adjustment layer (PSAL) to increase the phase shift on reflection of the top electrode within a range, which also improves the light out-coupling. By adjusting the thickness of PSAL, the CIE_x,y of devices, which utilize 2, 7-Di-pyrenyl-9, 9-spiro-bifluorene (DPSF) as emitting layer, changes from (0.16, 0.50) to (0.18, 0.37). The maximum current efficiency of 7.1 cd/A is acquired under 4.5 V with an increasing luminance of 139 cd/m². Compared with adjusting the total thickness of organic layer, it is more beneficial for achieving blue TEOLEDs with high efficiency.

Keywords

Phase Shift / Resonance Wavelength / Resonant Wavelength / Metallic Electrode / Triphenylamine

References

[1] ChenC.-W., LinC.-L., WuC.-C.. Appl. Phys. Lett., 2004, 85: 2469

[2] LeeC. J., PodeR. B., HanJ. I.. Appl. Phys. Lett., 2006, 89: 253508

[3] MoonD. G., PodeR. B., LeeC. J., HanJ. I.. Mat. Sci. Eng. B-Solid, 2005, 121: 232

[4] HanS., HuangC., LuZ.-H.. J. Appl. Phys., 2005, 97: 093102

[5] PengH. J., SunJ. X., ZhuX. L., YuX. M., WongM., KwokH. S.. Appl. Phys. Lett., 2006, 88: 073517

[6] WuF., MengY., XieG., ChenP., ZhaoY.. Journal of OptoelectronicsLaser, 2008, 19: 1287

[7] SunS., TakeshiF., CaoJ., ZhuW.-q., JiangX., ZhangZ.-l., WeiB.. Journal of OptoelectronicsLaser, 2009, 20: 609

[8] HsuS. F., LeeC. C., HuA. T., ChenC. H.. Current Applied Physics, 2004, 4: 663

[9] HsuS.-F., LeeC.-C., HwangS.-W., ChenH.-H., ChenC. H., HuA. T.. Thin Solid Films, 2005, 478: 271

[10] DjurišicA. B., RakicA. D.. Appl. Opt., 2002, 41: 7650

[11] BurinA. L., RatnerM. A.. J. Phys. Chem. A, 2000, 104: 4704

[12] MengY., XieW., XieG., ZhangL., ZhaoY., HouJ., LiuS.. Optics Express, 2009, 17: 5364

[13] WuZ., GuoH., WangJ.. J. Phys. D: Appl. Phys., 2006, 39: 5160