Phase evolution and photoluminescence enhancement of CePO₄ nanowires from a low phosphate concentration system

Uniform CePO₄ nanowires have been successfully synthesized in a low phosphate concentration system through a single-step hydrothermal process. The low phosphate concentration might decrease the surface PO₄ ³⁻ adsorption of the as-synthesized CePO₄ nanowires efficiently and benefit their photoluminescence. The CePO₄ nanowires were identified to go through phase evolution from pure monoclinic to mixed hexagonal and monoclinic phase by only increasing the initial molar ratio of cerium and phosphate source (denoted as Ce/P). Interestingly, the strongest photoluminescence was observed in the CePO₄ nanowires synthesized with the initial Ce/P of 4:1, which proved to be the critical phase evolution point between the hexagonal and monoclinic CePO₄. Therefore, the strong photoluminescence could be explained by the existence of the structure-sensitive energy level in the CePO₄. This kind of photoluminescence enhancement would be a meaningful reference for design of other photoluminescent materials, in which the photoluminescent emission might be related to the structure-sensitive energy level. Additionally, the growth processes of CePO₄ nanowires based on related well-designed experiments were proposed.