Enhanced efficiency and brightness in organic light-emitting devices with MoO₃ as hole-injection layer

Abstract

The organic light-emitting devices (OLEDs) using 4,4’,4”-tris{N-(3-methylphenyl)-N-phenylamin}triphenylamine (m-MTDATA) and MoO₃ or 1,3,5-triazo-2,4,6-triphosphorine-2,2,4,4,6,6-tetrachloride (TAPC) and MoO₃ as the hole-injection layer (HIL) were fabricated. MoO₃ can be expected to be a good injection layer material and thus enhance the emission performance of OLED. The highest occupied molecular (HOMO) of MoO₃ is between those of m-MTDATA or TAPC and N,N’-bis-(1-naphthyl)-N,N’-diphenyl-1,1’-biphenyl-4,4’-diamine (NPB), which reduces the hole-injection barrier and improves the luminance of the OLEDs. The current efficiency is improved compared with that of the device without the MoO₃ layer. The highest luminous efficiency of the device with 2-nm-thick MoO₃ as HIL is achieved as 5.27 cd/A at 10 V, which is nearly 1.2 times larger than that of the device without it. Moreover, the highest current efficiency and power efficiency of the device with the structure indium-tin oxide (ITO)/TAPC (40 nm)/MoO₃ (2 nm)/TcTa:Ir(ppy)₃ (10%, 10 nm)/ tris-(8-hydroxyquinoline) aluminium (Alq) (60 nm)/LiF (1 nm)/Al are achieved as 37.15 cd/A and 41.23 lm/W at 3.2 V and 2.8 V, respectively.

References

[1] JabbourG E, KippelenB, ArmstrongN R, PeyghambarianN. Applied Physics Letters, 1998, 73: 1185

[2] KidoJ, MatsumotoT. Applied Physics Letters, 1998, 73: 2866

[3] BenorA, TakizawaS Y, Perez-BolivarC, AnzenbacherP. Applied Physics Letters, 2010, 96: 243310

[4] HungL S, TangC W, MasonM G. Applied Physics Letters, 1997, 70: 152

[5] QiuC F, WangL D, ChenH Y, WongM, KwokH S. Applied Physics Letters, 2001, 79: 2276

[6] QiuY, GaoY D, WeiP, WangL D. Applied Physics Letters, 2002, 80: 2628

[7] LiF, TangH, AndereggJ, ShinarJ. Applied Physics Letters, 1997, 70: 1233

[8] HuW, ManabeK, FurukawaT, MatsumuraM. Applied Physics Letters, 2002, 80: 2640

[9] XieG, ZhangZ, XueQ, ZhangS, ZhaoL, LuoY, ChenP, QuanB, ZhaoY, LiuS. Organic Electronics, 2010, 11: 2055

[10] WenX, YinY, LiY, LiuS, ZhangL, MaN, ShanG, XieW. Organic Electronics, 2014, 15: 675

[11] CaiC, SuS-J, ChibaT, SasabeH, PuY-J, NakayamaK, KidoJ. Organic Electronics, 2011, 12: 843

[12] SunJ W, LeeJ-H, MoonC-K, KimK-H, ShinH, KimJ-J. Advanced Materials, 2014, 26: 5684

[13] HuW, MatsumuraM. Applied Physics Letters, 2002, 81: 806

[14] ChanI M, HsuT Y, HongE C. Applied Physics Letters, 2002, 81: 1899

[15] WenX, YinY, LiY, LiuS, ZhangL, MaN, ShanG, XieW. Organic Electronics, 2014, 15: 675

[16] LiuY-F, FengJ, ZhangY-F, CuiH-F, YinD, BiY-G, SongJ-F, ChenQ-D, SunH-B. Organic Electronics, 2014, 15: 478

[17] YANGH-s, WUL-s, WUJ-m, WUZ-w. Journal of Optoelectronics·Laser, 2015, 26: 1273

[18] WANGR-x, FANC-j, YANGX-H. Journal of Optoelectronics·Laser, 2015, 26: 649