Engineering B‒N Covalent Bond‐Fused Naphthalene Derivatives for Narrowband Yellow Emission and Power‐Efficient White OLEDs

and Commission Internationale de l'Éclairage (CIE) coordinates of (0.342, 0.542). Further device optimization leads to a standard white electroluminescence with CIE coordinates of (0.334, 0.342). The unprecedented performance indicates the great potential of B‒N covalent bond-fused naphthalene derivatives in power-efficient white OLEDs.