Aqueous solution-processed InCl3 as an effective buffer layer to improve hole injection in simplified phosphorescent organic light emitting diodes

Abstract An effective anode buffer layer is demonstrated by aqueous solution-processed indium trichloride ( s InCl 3 ) in simplified phosphorescent organic light emitting diodes (PhOLEDs). The hole injection is improved in s InCl 3 based PhOLEDs exhibiting better performance with decreased driving voltage, increased power efficiency compared to the traditional ultraviolet-ozone (UV-Ozone) treated ones. Then, the mechanism for the enhanced hole injection is investigated. Better electrode contact is found in s InCl 3 based hole dominated devices. Higher work function (∼0.60 eV) is detected on the s InCl 3 -ITO anode and stable In Cl bonds are formed on its surface compared to the UV-Ozone treated one according to the photoelectron spectroscopy.