Effect of Self-Assembled Monolayer on Polymeric and Organic Light-Emitting Diodes

In this report, we discuss the effect of FSAM on both hole-injection and hole-transport functions. The thiophene derivative PEDOT:PSS is widely used as a hole-injection layer of conducting-polymer based LEDs (PLEDs). However, since PEDOT:PSS has some problems of strong acidity and metal cation impurities, a substitute material has been developed as a substitute. We used FSAM as a directly hole-injection layer of PLEDs and a single Alq3 layer. The introduction of FSAM lowered the driving voltage of devices and improved EL efficiency per current. In the former case, the EL properties of PLED with PEDOT:PSS is superior to those of PLED with FSAM. In the latter case, it was found the increase in hole injection contributed to high conduction of OLEDs. We reviewed the basic characteristics of polymer and OLED using FSAM.