Effect of the Interface Improved by Self-Assembled Aromatic Organic Semiconductor Molecules on Performance of OLED

Abstract

This work focuses on characterization the performance of enhanced interface of organic light emitting diode (OLED) device by Self-assembled Monolayer (SAM) technique. SAM technique is popular in order to overcome the weak bonding at the organic/inorganic interface in OLED. New generation of SAM molecules, phenyl-benzoic-acid (PBA, 4-(9H-carbazol-9-il) benzoic acid (MZ39), 4-(2,5-di-2thienyl-1H-pyrrol-1-il) benzoic acid (MZ25) were coated on between Indium Tin Oxide (ITO). The two configuration of ITO/SAM/TPD/Al and ITO/TPD/Al diode were fabricated as hole-only device to show the contribution of SAM layer on the hole mobility calculated by Space Charge Limited Current (SCLC) technique. The optical characterization of OLED devices with configuration ITO/TPD/Alq3/Al and ITO/SAM/TPD/Alq3/Al was performed to see the effect of aromatic SAM molecules on the luminance and quantum efficiency. Especially, the SAM modified OLED has a maximum luminance of 397 cd m−2. All devices containing SAM layer showed better performance than reference one.