In this work, The authors optimized blue phosphorescent OLEDs using a dual emitting layer structure and employed two different approaches. Significant improvements were achieved in both EQE and luminance. The maximum EQE values reached 17.49% and 18.99%, while the luminance increased to 15,890 cd m⁻². Additionally, the concept of incorporating a hole-blocking layer into the middle of the emissive layer to create a dual emitting layer structure is highly innovative. This dual emitting layer approach provides a new strategy for fabricating high-efficiency and high-brightness OLEDs. I suggest publish this paper in the Journal of Materials Chemistry C after minor revisions. The following recommendations are made for consideration.
1. Figure 3(c) analyzes the energy transfer diagram within the emitting layer. It is recommended to indicate the specific values of the triplet and singlet states in the figure.
2. In Figure 8(e), the image size is inconsistent. It is recommended to redraw Figure 8.
3. For TPBi as the hole-blocking layer in the emitting layer, both its thickness and position within the emitting layer affect the device. The article only conducted experiments related to thickness but did not investigate the effect of position. It is recommended to supplement this aspect.
4. The second method did not include device lifetime testing, and device lifetime should be supplemented.

accept as it is