Organic light-emitting diode (OLED) is a main stream display technology, which has been used for watch, cell phone, pad, laptop, TV, and AR/VR/MR applications. Among three primary colors, blue organic light-emitting diode (OLED) exhibits much shorter lifetime than red and green ones due to its wide bandgap nature. Although red and green phosphors are commercially available for display application, low-efficiency fluorophore is still used for a blue OLED which barely achieves acceptable operation lifetime in mass production. In this talk, we propose a device structure, which managed non-emissive triplet excitons in a blue OLED by improving the triplet-triplet fusion (TTF) process for higher efficiency and reducing exciton-polaron quenching for longer lifetime. ~20% increase in device efficiency was observed in this blue TTF-OLED. More interestingly, 4x increase in operation lifetime was achieved in this device, verified by an OLED mass production line.