LAUSR

In this study, PAP‐1‐Ch is presented, a novel anthracene‐based host material, designed specifically for high‐efficiency and stable blue fluorescent organic light‐emitting diodes (OLEDs). The unique molecular architecture of PAP‐1‐Ch integrates a chrysene substituent of anthracene, achieving an optimal balance between steric hindrance and molecular linearity. This balance plays a critical role in minimizing π–π stacking, which effectively prevents fluorescence quenching while promoting favorable horizontal molecular orientation of up to 91.5% and enhancing the photoluminescence quantum yield (PLQY) up to 93.1%, thereby significantly improving the out‐coupling efficiency. Furthermore, the finely tuned structure of PAP‐1‐Ch results in superior charge carrier mobility and a more balanced electron/hole injection current. Devices fabricated with PAP‐1‐Ch as the host material demonstrated remarkable performance metrics, achieving blue color purity with Commission Internationale de l'Eclairage (CIE) coordinates of (0.136, 0.130), a luminance efficiency of 13.2 cd A−1, a maximum external quantum efficiency (EQE) of 12.6%, and an operational lifetime (LT95) of over 12 000 h at 100 cd m−2. These results represent a substantial advancement in the development of high‐efficiency, stable blue fluorescent OLEDs, paving the way for their application in next generation of high‐end displays.