Red Quantum Dot Light‐Emitting Diodes With 31.3% EQE Enabled by a Pyridyl‐Triazine Electron Transport Material

ABSTRACT Quantum dot light‐emitting diodes (QLEDs) represent a leading technology for future display applications. However, interfacial non‐radiative losses and charge injection imbalance remain critical challenges limiting device performance. Here, a pyridyl‐triazine electron transport layer (ETL) based on 2,4,6‐Tris(3’‐(pyridine‐3‐yl) biphenyl‐3‐yl)‐1,3,5‐triazine (TmPPPyTz) is introduced to suppress the interfacial non‐radiative recombination driven by Zn 2+ ‐related surface defects on red quantum dots. Concurrently, combined with an optimized hole‐transporting layer comprising poly(9‐vinylcarbazole) (PVK) blended with 25 wt.% tris(4‐carbazoyl‐9‐ylphenyl)amine (TCTA), balanced carrier injection is achieved. The resulting red QLEDs with all‐organic charge transport layers exhibit unprecedented performance metrics: an external quantum efficiency of 31.3%, a current efficiency of 39.0 cd A −1 , a power efficiency of 35.3 lm W −1 , and a T 50 lifetime of 7513 h at 100 cd m −2 . These efficiency values correspond to improvements of 42%, 35% and 104% over conventional ZnMgO‐ETL devices (22.0%, 28.8 cd A −1 , and 17.3 lm W −1 ). This work establishes a new design strategy for high‐performance QLEDs through molecular engineering of electron transport materials.