An organic white light electroluminescent device with high performances is designed and fabricated. In this work

the efficiency of blue light emitting was improved only by designing the device structure

which increase the performances of the white light emitting device. Using a hole blocking material (BCP) to controlling the light emitting zone based on NPB layer

we obtained blue light emitting

which comes from excited NPB molecules. Similarly

we obtained yellow light emitting by doping in NPB layer with rubrene. Base on the above

through partly doped NPB layer with rubrene

in which the doped part of NPB layer emits orange light and the undoped part contributes to blue light

we can obtain white light emitting. Because the undoped part of NPB is near the interface of NPB/BCP and this layer is very narrow

only about 3nm

the efficiency of blue light emission is increased

which results the improvement of the performances of white light emitting device. The device has a maximum brightness of 17000cd/m

2

(at a driving voltage of 22V)

and the maximum electroluminescent and power efficiency are 3.05cd/A and 1.92lm/W (at a drive voltage of 5V

the current density of 0.5mA/cm

2

)

respectively. At drive voltage of 5V

the CIE coordinate of the device is (x =0.317

y =0.328)

which is very close to the equi energy point.