Optimization of Eu-doped lanthanum tungstate nanophosphors via surface modification for superior red luminescence and photonic applications

• PVA-modified Eu3+-doped lanthanum tungstate nanophosphors achieve 99.6% color purity and CIE coordinates (0.6351, 0.3644), making them highly suitable for WLEDs and latent fingerprint detection. • Surface modification with PVA significantly enhances red luminescence at 616 nm by suppressing nonradiative recombination and improving surface passivation. • The optimized nanophosphors exhibit extended luminescence lifetimes and excellent biocompatibility, indicating potential for biomedical applications. • This work provides a facile hydrothermal-assisted solid-state synthesis route for high-performance red-emitting nanophosphors with tunable optical properties via surface engineering.