High ultraviolet stability red phosphorescent organic light-emitting diode based on fluorinated copper phthalocyanine interface modification

Abstract The outdoor application of organic light-emitting diodes (OLEDs), such as in automotive lighting and mobile phone screens, is limited by reliability degradation under ultraviolet (UV) irradiation, with the interface between the indium tin oxide anode and the hole transport layer being the most UV-sensitive region. To synergistically enhance interfacial stability and device performance, this study incorporates fluorinated copper phthalocyanine (F ₁₆ CuPc) as an interfacial functional layer into red OLEDs. An optimal 30 nm thickness of F ₁₆ CuPc achieves excellent optical performance by providing efficient UV shielding while maintaining high visible-light transmittance. The results demonstrate that the F ₁₆ CuPc layer exhibits intrinsic strong UV absorption, and its high molecular planarity promotes dense molecular stacking. Experiments confirm that its core chemical bonds remain highly inert under UV irradiation, effectively suppressing interfacial photo‐oxidation, while also improving hole injection efficiency. The resulting F ₁₆ CuPc‐based OLED achieved a maximum luminance of 26 554 cd m ² and a peak external quantum efficiency of 15.28%. More importantly, under continuous 365 nm UV irradiation at an intensity of 30 mW cm ⁻² , the operational lifetime of the device was extended from 2553 h to 2710 h. This work not only confirms F ₁₆ CuPc as a UV‐stabilizing interfacial modifier, but also reveals, across multiple scales, the underlying mechanism by which it enhances device reliability, thereby offering a novel interface‐engineering strategy for developing highly stable organic optoelectronic devices.