Metal oxides as a hole-injecting layer for an organic electroluminescent device

Abstract

We demonstrate that by using thin films of metal oxides, such as vanadium oxide (VOx), molybdenum oxide (MoOx) and ruthenium oxide (RuOx), as a hole-injecting layer for an organic electroluminescent (EL) device consisting of N,N'-diphenyl-N,N-bis(3-methylphenyl1)1,1'-biphenyl-4,4' diamine (TPD) and tris-(8-quinolinolato) aluminium (Alq), the EL device performance can be significantly improved. The `operating voltage' of the device is reduced with respect to a device with a well known indium - tin-oxide (ITO) electrode for hole injection. We consider that the improvement of the operating voltage is attributable to the lower energy barrier for hole injection at the metal oxide/TPD interface.

Space-charge-limited hole current in poly(9,9-dioctylfluorene) diodes

“…17,18 Specifically molybdenum trioxide ͑MoO 3 ͒ has proven to be an attractive material and has been used as a HIL in organic LEDs based on small molecules, [19][20][21][22] as buffer layer in organic solar cells 23,24 and as connecting layer in tandem organic LEDs. 25 The working mechanism of MoO 3 as HIL is generally ascribed to the formation of an interfacial dipole and consequently a reduction of the injection barrier.…”

Light-emitting Organic Photovoltaic Devices Based on Rubrene/PTCDI-C13 Stack

“…The ITO coated glass was thoroughly cleaned using the process of scrubbing, ultrasonication, and irradiation in an UV-ozone chamber. Firstly, molybdenum trioxide (MoO 3 ) [16][17][18] as an effective hole injection layer was deposited on ITO substrate. Absorption spectra of evaporated thin film materials were measured using a fiber optical spectrometer (Ocean Optics, S2000) and deuterium/tungsten lamps (Hamamatsu Photonics, L10671).…”

Bandgap Science for Organic Solar Cells

“…As acceptors, organic dopants such as F 4 -TCNQ [30,31] and inorganic dopants like MoO 3 , V 2 O 5 , etc. [32,33] were found. In terms of donors that are relatively stable in air, Harada et al found a Ru-complex and applied it to fabricate pn-homojunctions in zinc phthalocyanine [34,35] and pentacene [36].…”