High efficiency phosphorescent white organic light-emitting diodes (PHWOLEDs) were developed by using a spirofluorene based phosphine oxide (SPPO1) as a host material in blue emitting layer. A stack structure of red:green/blue with an interlayer was used and the device performances of PHWOLEDs were investigated according to host composition in red green emitting layer and the interlayer thickness. The use of SPPO1 as a host in the blue emitting layer resulted in a high quantum efficiency of 13.5% and a current efficiency of 27.6 cd/A with a color coordinate of (0.37, 0.43). (C) 2010 Elsevier B.V. All rights reserved.