Role of new synthesized diethylenetriamine-based protic ionic liquids in organic semiconductor devices

Abstract

The charge carrier transport and related transport layers are extremely essential issue for obtaining high-efficient Organic Light Emitting Devices (OLEDs) and high-performance Organic Field Effect Transistor (OFETs). In an attempt to light on the effects of diethylenetriamine (DETA) based protic ionic liquids (PILs) on OLEDs and OFET, PILs were used as a hole transport layer and dielectric layer in OLEDs and OFETs, respectively. Charge transfer properties of synthesized two novel DETA based PILs (PIL1 and PIL2) on OLED device performance were investigated by spinning on poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) due to their ionic characteristics. The PIL2 based OLED device showed threefold luminance (1038 cd/m(2)) compared to reference device (360 cd/m(2)) without effecting its light output emission wavelength. When analyzed OFET performances, device with PIL1 possessed the highest performance in terms of low threshold voltage (VTh similar to 1.5 V), operating voltage (V similar to 5 V) and reproducibility in the ambient atmosphere in comparison to device without PILs. Moreover, Density Functional Theory (DFT) calculations and impedance spectroscopic analysis of ionic liquids (ILs) were investigated. The carrier transport properties and mobility measurement has been identified with impedance spectroscopy of the devices. PIL1 had p-type transport property with mobility up to 0.198 cm(2)/Vs while the device without PILs had mobility 0.0237 cm(2)/Vs.