Side Chain Effects on High‐Performance PPIAn2N‐Derived Dual‐Functional Devices for Balanced Blue Light Emission and UV Detection

Abstract Dual‐function devices are being used in smart wearable electronics and human‐machine interaction because of their special functions. In this study, three modified PPIAn2N‐based emitters— PPIAn2N‐CH ₃ , PPIAn2N‐CN , and PPIAn2N‐F —are synthesized and applied them in dual‐functional devices, specifically organic light‐emitting diodes (OLEDs) and UV organic photodetectors (UVOPDs). Each of these molecules exhibits hybridized local and charge transfer (HLCT) excited states, which results in blue emission both in solution and in thin films. However, the proportion of local excited (LE) states to charge transfer (CT) states differs among the molecules. The non‐doped OLED using PPIAn2N‐F displayed outstanding performance, emitting deep blue light at 456 nm, with a Commission Internationale de l'Éclairage (CIE) coordinate of (0.14, 0.14), and achieving a maximum external quantum efficiency (EQE) of 8.52%. Additionally, the PPIAn2N‐F ‐based OLED‐UVOPD demonstrated excellent UV detection capabilities, with a detectivity ( D ^* ) of 8.60 × 10 ¹⁰ Jones. The device achieved a well‐balanced EQE/ D ^* ratio, indicating an optimal combination of luminescence efficiency and detection sensitivity. These findings underscore the potential of multifunctional devices operating in the blue emission spectrum, paving the way for advancements in dual‐functional OLED and UV detection technologies.