Phase evolution and photoluminescence enhancement of CePO_4 nanowires from a low phosphate concentration system

摘要

Uniform CePO_4 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 PO_4 ~(3-) adsorption of the as-synthesized CePO_4 nanowires efficiently and benefit their photoluminescence. The CePO_4 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 CePO_4 nanowires synthesized with the initial Ce/P of 4:1, which proved to be the critical phase evolution point between the hexagonal and monoclinic CePO_4. Therefore, the strong photoluminescence could be explained by the existence of the structure-sensitive energy level in the CePO_4. 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 CePO_4 nanowires based on related well-designed experiments were proposed.