Low sublimation temperature cesium pivalate complex as an efficient electron injection material for organic light-emitting diode devices

Abstract

Cesium pivalate ((CH 3) 3CCOOCs) has been synthesized and applied as an electron injection material for organic light-emitting diodes, which showed low sublimation temperature of 180 °C. Typical bilayer structure of ITO/NPB (60 nm)/Alq 3 (50 nm)/EIL/Al was used to evaluate the electron injection efficacy of (CH 3) 3CCOOCs, the results showed (CH 3) 3CCOOCs/Al exhibits better electron injection than LiF/Al cathode and the power efficiency was improved by about 19% at current density of 50 mA/cm 2. More interestingly, in the typical three layer OLED structure ITO/2-TNATA (60 nm)/NPB (10 nm)/Alq 3:2% C545T (40 nm)/MADN (15 nm)/(CH 3) 3CCOOCs (2 nm)/Al, the maximum current efficiency is up to 20 cd/A with Commission Internationale d’Eclairage (CIE x , y ) color coordinates of ( x = 0.30, y = 0.65) at current density of 140 mA/cm 2, which indicates that the non-aromatic alkali metal complex can also have good match with the chemically stable compound and exhibit good electron injection properties.