利用两种颜色的发光层制备了光谱稳定的高效混合WOLED。其中蓝光发光层用14%质量分数的BNE掺杂在BePP2中，橙光发光层用1%质量分数的Ir(bt)2(acac)掺杂在49.5%质量分数的NPB和49.5%质量分数的BePP2组成的混合主体中。在不利用任何光耦合技术的条件下，器件在亮度为100 cd/m2时，功率效率可以达到39 lm/W；当亮度提高到1 000 cd/m2时，效率仅发生轻微滚降至27.5 lm/W。器件的光谱稳定，亮度在1 000 cd/m2和10 000 cd/m2时，CIE坐标分别为(0.37, 0.48) 和(0.37, 0.47)。良好的光谱稳定性归结于设计的双极性中间层平衡了其两侧激子的产生。

Highly efficient hybrid white organic light-emitting diode (WOLED) with stable emission spectrum was fabricated by using two separately monochromatic emission layers (EML). The blue emissive layer was based on 14%(mass fraction) trans-1,2-bis(6-(N,N-di-p-tolylamino)-Naphthalene-2-yl)ethene (BNE) doped in BePP2, and the orange emissive layer was based on 1%(mass fraction) Ir(bt)2(acac) doped in a mixed-host of 49.5%(mass fraction) NPB and 49.5%(mass fraction) BePP2. Without the use of any outcoupling techniques, this device can achieve a power efficiency of 39 lm/W at brightness of 100 cd/m2, and slightly rolls off to 27.5 lm/W at brightness of 1 000 cd/m2. There is nearly no color shift with the bias voltages as the Commission Internationale de L’Eclairage (CIE) coordinates are (0.37, 0.48) and (0.37, 0.47) at 1 000 cd/m2 and 10 000 cd/m2, respectively. The stable emission spectrum can be contributed to the well designed ambipolar interlayer which successfully balances the exciton generation evenly on its both sides.