This study investigated the electro-optic properties of organic light-emitting diode (OLED) devices with the addition of an interlayer. A device with the perfluorododecyl-1H,1H,2H,2H-triethoxysilane–perfluorotetradecyl 1H,1H,2H,2H-triethoxysilane mixture (hybrid solution) membrane applied to the hole injection layer (HIL) using a self-assembled monolayer (SAM), along with N,N’-Bis (naphtha-len-1-yl)-N,N’-bis(phenyl)-2,2’-dimethylbenzidine (α-NPD) applied to the hole transport layer (HTL), was fabricated and subsequently assessed. Compared to the device without an HIL, the device with HIL using SAM showed a luminance of 1630.16 (Cd/m2) at the maximum cut-off voltage of 11 V, and the efficiency was increased to ≥200% from the initial turn-on voltage of 3 V to the maximum cut-off voltage. These results suggest that adding an interlayer and the consequent carrier ladder effect led to more efficient injection and transport, possibly lowering the hole injection barrier and allowing excellent power efficiency.