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

Cesium pivalate ((CH₃)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)/Alq₃ (50 nm)/EIL/Al was used to evaluate the electron injection efficacy of (CH₃)₃CCOOCs, the results showed (CH₃)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/cm². More interestingly, in the typical three layer OLED structure ITO/2-TNATA (60 nm)/NPB (10 nm)/Alq₃:2% C545T (40 nm)/MADN (15 nm)/(CH₃)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/cm², 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.