To solve serious efficiency roll-off of phosphorescent organic light-emitting devices (OLEDs) that still hinders further development of OLEDs, ultrasonic spray coating poly(3, 4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) films were proposed as transparent electrode for fabricating red, green and blue OLEDs. The water-soluble PSS molecular chain, which is insulating, was retained in the PEDOT:PSS transparent electrode by utilizing the high utilization rate of ultrasonic spraying materials, resulting in hole buffer effect of such PEDOT:PSS transparent electrode. Dual functions of this type of PEDOT:PSS transparent electrode is used to improve carrier balance under high current density, reduce the polaron density in the red, green and blue emitting layers, and finally improve the efficiency roll-off of these OLEDs. From the luminance of maximum current efficiency to the luminance of 10 000 cd/m², efficiency roll-off of red, green and blue devices is only 14.9%, 12.4% and 16.0%, respectively. The results show that the introduction of dual functional electrode significantly improves carrier balance in organic luminescent devices, and is universal to reduce efficiency roll-off of three primary color devices, which is of great significance to achieve high brightness efficienct OLEDs.