Low-Temperature Evaporable Re2O7: An Efficient p-Dopant for OLEDs
Jia, Y; Duan, L; Zhang, D; Qiao, J; Dong, G; Wang, L; Qiu, Y
| HERO ID | 3576384 |
|---|---|
| In Press | No |
| Year | 2013 |
| Title | Low-Temperature Evaporable Re2O7: An Efficient p-Dopant for OLEDs |
| Authors | Jia, Y; Duan, L; Zhang, D; Qiao, J; Dong, G; Wang, L; Qiu, Y |
| Journal | Journal of Physical Chemistry C |
| Volume | 117 |
| Issue | 27 |
| Page Numbers | 13763-13769 |
| Abstract | Transition-metal oxides (TMOs) are one of the most promising kinds of p-doping materials for organic semiconductors. However, to be compatible with organic materials, low-temperature evaporable TMOs are highly desirable. Rhenium(VII) oxide with a very low melting temperature of only 225 degrees C, which is the lowest among all TMO dopants, is first investigated as a p-dopant in N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4-diamine (NPB). Systematic studies are performed compared with ReO3, a different valence state oxide of rhenium. Hole mobility improvement from 5.38 X 10(-4) to 5.88 x 10(-3) cm(2)/(V s) at an electric field of 3 x 10(5) V/cm is achieved by doping Re2O7 into NPB. Lower valence states of Re species in Re2O7-doped NPB than ReO3 are observed by XPS study, indicating stronger charge transfer between Re2O7 and NPB. Temperature-dependent I-V study reveals lower hole injection barrier of Re2O7 than ReO3 in hole-only devices. Crystallinity of NPB flints is found to be the same before and after doping by XRD study. Absorption spectrum study reveals higher stability of R2O7-doped NPB than ReO3 in air. Hole current is enhanced by three orders of magnitude at 2 V when utilizing both rhenium-oxide-doped NPBs in hole-only devices. OLED devices with both rhenium-oxide-doped NPBs as hole injection layer (HIL) show a similar efficiency of 3.3 Cd/A at 300 mA/cm(2). Also, driving voltage is reduced from 2.6 V for pure NPB to 2.5 and 2.4 V for Re2O7 and ReO3 doped NPB, respectively. |
| Doi | 10.1021/jp400003m |
| Wosid | WOS:000321883600001 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |