Unusual White Electroluminescence of Organic Light Emitting Diodes Based on Imidazoles Compounds

In this work, imidazoles derivatives as luminescent materials have been investigated. In continuation, light-emitting diodes (OLEDs) were prepared using these compounds in a guest environment containing PVK as a hole transport material and PBD as an electron transport material. A device with the structure of ITO/PEDOT:PSS (60 nm)/PVK:PBD:‌‌ Guest (80 nm)/Al (180 nm) was fabricated. The electroluminescence spectrum of device red-shifted respect in PVK:PBD. The overlap between the absorption spectrum of the imidazoles and the emission spectrum of PVK:PBD caused a redshift. By variation of functional groups on these compounds, a shift in wavelength toke placed in the electroluminescence spectrum. By mixing imidazoles derivatives, a white light-emitting devices was prepared. This happened due to the rare electroplex phenomena in the emitting layer.