Asymmetric anthracene derivatives as electron transport materials for high performance OLEDs

An asymmetric anthracene material, 2-phenyl-1-(4-(10-(6-phenylpyridin-3-yl) anthracen-9-yl)phenyl)-1H-benzo[d] imidazole (BPA), was functionalized by naturally occurring xanthine derivatives as benign biomaterials for application as exceptional electron transport layers (ETLs) in organic light emitting diodes (OLEDs). In these structures, five xanthine derivatives were attached onto the phenyl rings existing on the right and left sides of the BPA core so that ten functionalized compounds were obtained and their structural, physico-chemical, optoelectronic, and electron mobility characteristics were examined through density functional theory (DFT) studies. For all ETLs, the LUMO energies were higher compared to the conduction band of PhtBuPAD used as conventional fluorescent dopant in the emitter mixture layer, leading to easy electron injection from ETLs toward the emitter layer. All functionalized BPA materials revealed high electron mobility values in the range of 0.027 to 0.411 cm²V⁻¹s⁻¹, which were bigger than that of pure BPA (0.026 cm²V⁻¹s⁻¹). These results confirmed that the functionalized BPA samples could be suitable ETL materials for efficient OLEDs.