Assistance of partially reduced MoO3 interlayer to hole-injection at iron phthalocyanine/ITO interface evidenced by photoemission study

► Pronounced gap states were yielded in partially reduced MoO3 (MoOx) interlayer. ► A barrier of 0.45 eV was derived for electron extraction from FePc to MoOx smaller than to MoO3. ► The energy level alignment diagrams were obtained for the FePc/MoO3 and FePc/MoOx interfaces. ► The nominal thickness was optimized to be 3 nm for MoO3 interlayer.