We fabricated a single-EML WOLED to further simplify the device by co-doping green and red phosphors into Bepp2[62], as shown in Fig. 10a. TAPC was used as the HTL, green Ir(ppy)2(acac) and red Ir(PPQ)2(acac) co-doped into Bepp2 as the EML and ETL. The strategy of doping concentration regulation was also applied to the hybrid WOLED. A maximum power efficiency of 46.8 lm/W and EQE of 16.5% were achieved. The power efficiency still reached 30.3 lm/W even at 1000 cd/m2. The spectra are shown in Fig. 10b. Although the CRI values are more than 88, the white emission in the single-EML device is not stable, which could result from the complicated emission processes. However, the simple device structure is favored for reducing the fabrication processes and thus lowering the manufacturing cost.