Organic light emitting devices (OLEDs) are provided. An exemplary OLED includes a substrate, a first electrode, a second electrode, and an organic layer between the first and second electrodes having a hole injection layer and an emissive layer. The emissive layer includes red, green and blue emissive layers. The organic layer further includes an auxiliary layer selected from a first auxiliary layer between the hole injection layer and the red emissive layer for adjusting the resonance cycle of red light, a second auxiliary layer between the hole injection layer and the green emissive layer for adjusting the resonance cycle of green light, and combinations thereof. The material of the auxiliary layer is different from the material of the hole injection layer. The organic light emitting device has low turn-on voltage, high current density, high luminance, high current efficiency, high power, long life-time, and excellent color purity.