Chemical modifications of red phosphor LaPO4:Eu3+nanorods to generate white light

Abstract

In this work, we report on white light generation by chemical modification of red phosphor LaPO₄:Eu³⁺ nanorods. The method includes an initial hydrothermal crystallization of single hexagonal phase LaPO₄:Eu³⁺ nanorods with surface hydration layers, followed by the deprotonation of oleic acid when reacted with surface hydroxyls adjacent to the oxygen vacancies for chemical bonding of oleic acid species. The resulting oleic acid/LaPO₄:Eu³⁺ surface complexes exhibited a synergy of the relevant interface mid-gap states and red emission of Eu³⁺ which led to surprisingly tunable colors from purplish pink through green-blue to white when simply varying the excitation lines to longer wavelengths. As a consequence of the tunable colors, an intense white light emission was readily achieved at optimum excitation wavelengths of 380 and 395 nm. The findings reported in this work may open up new avenues for simplified white light generation and its relevant technologies.