Space-charge-limited charge injection from indium tin oxide into a starburst amine and its implications for organic light-emitting diodes

Abstract

We have investigated the hole-injection characteristics from indium tin–oxide (ITO) into 4,4′,4″-tris{N,-(3-methylphenyl)-N-phenylamino}triphenylamine (m-MTDATA) and have measured the hole-carrier drift mobility of this compound in single-layer ITO/m-MTDATA/Au structures. We have found that ITO is able to provide trap-free space-charge-limited currents over a wide range of film thicknesses and have established unambiguously that the ITO/m-MTDATA is an ideal Ohmic contact at high electric fields. Our observations clarify the role of m-MTDATA as a voltage-lowering hole-injecting buffer layer in organic light-emitting diodes.

High Efficiency Red Phosphorescent Organic Light-Emitting Diodes with Simple Structure

“…As seen from the results of Fig. 14(a) (Giebeler et al, 1998) at ITO and m-MTDATA interface was reported. Whereas, the NPB hole only device had reported to have the injection limited current behavior.…”

The Effect of Annealing of Organic Thin Films on Charge Injection in Organic Electroluminescent Devices.

“…The hole-drift mobilities of of 2-TNATA and p-BPD are also similar to those of m-MTDATA (2.7 X 10"5 cm2V"is"1) and TPD (1.1 X 10"3 cm2V"is"1) [15].…”

Organic light emitting diodes (OLEDS) and OLED-based structurally integrated optical sensors

“…It was not only attributed to failure of the Ohmic contact presumption at the electrode/organic interface, but also to the energy barriers between the organic layers. On the contrary, the SCLC model is easily accepted in much simpler structures, such as polymer LEDs [32] and single layer hole-only small molecular devices [33].…”

“…They are inherently advantageous as lowvoltage [32], miniaturizable [33], and flexible light sources [34,35]. Electrophosphorescent green and blue OLEDs with an external quantum efficiency of ~20% and ~12%, respectively, have been reported [35].…”