Effects of BPhen as Spacer Layer in Light Emitting Layer on Yellow OLED
We prepared yellow phosphorescent OLED devices,which used R 4B,GIrl as the green phosphorescent dopant,CBP as the main body material. We investigated the BPhen as spacer layer between the red and green emitting layers to regulate currieries recombination. The device structure was ITO Mo O3( 40 nm) /NPB( 40 nm) /TCTA( 10 nm) /CBP GIrl( 14% 20 nm) /BPhen( x nm) CBP: R 4B( 6% 10 nm) BCP( 10 nm) Alq3( 40 nm) /Li F( 1 nm) /Al( 1 000 nm) In this structure,x referred to six different thickness of BPhen in the devices. We studied its luminescent properties and controlled its spectra by adjusting the thickness of BPhen. The results show that appropriate thickness of BPhen can improve the performance of the device. When the thickness of BPhen is 6 nm,the performance of the device is the optimum. The maximum brightness is 11 270 cd m2 at 16 V,and the maximum efficiency is 24. 35 cd A. Meanwhile,the green and red peaks almost have the same intensity in the spectra which means the purest yellow of all devices,and the color coordinates close to( 0. 5,0. 5)