Large‐Area and Uniform Blade‐Coated Deep‐Blue Polymer Light‐Emitting Diodes Based on Triphenylethylene‐Encapsulated π‐Conjugated Polymer

Abstract Emerging large‐area flexible polymer light‐emitting diodes (PLEDs) are crucial for flat‐panel displays. The development of uniform, large‐area, flexible, and ultra‐deep‐blue PLEDs remains challenging owing to the lack of efficient and stable deep‐blue light‐emitting conjugated polymers with robust deep‐blue emission, excellent large‐scale solution‐processing capacity, and stable electrical properties. In this study, a multidimensional steric triphenylethylene (TPE) segment is introduced into the substitution side chain of polydiarylfluorenes (P‐F) for deep‐blue large‐area blade‐coated and flexible PLEDs. The encapsulation of backbone chains with extremely weak interchain π–π interactions facilitated the preparation of large‐area PLEDs via blade coating. Large‐area uniform P‐F films (16 cm 2 ) are fabricated. Flexible PLEDs are fabricated with efficient deep‐blue emission (CIE: 0.15, 0.07) and a maximum brightness of 2314 cd m −2 . Notably, the large‐area PLEDs exhibited a narrow‐band deep‐blue emission with a CIE of (0.15, 0.08) at ≈1000 mA cm −2 and an emitting area of 3.6 cm 2 . Furthermore, a preliminary patterned PLED array display with a pixel size of 800 × 1000 µm 2 is successfully created, which exhibited stable and uniform deep‐blue light‐emitting pixel performance (CIE: 0.15 0.08). These results demonstrated the effectiveness of the TPE encapsulation strategy for large‐area PLEDs.