Fabrication of Lanthanide Phosphate Nanocrystals with Well-Controlled Morphologies by Layer-by-Layer Adsorption and Reaction Method at Room Temperature

Here we report the preparation of crystallized lanthanide phosphate (LnPO4) nanostructures at room temperature on solid substrates by the layer-by-layer adsorption and reaction method comprising repetitive adsorption of lanthanide ions and subsequent reaction with phosphate ions. Taking the fabrication of LaPO4, for instance, the morphology of the nanostructured LaPO4 can be controlled between three-dimensional dandelion-like nanoarchitectures composing of single-crystalline one-dimensional nanoneedles and one-dimensional nanoneedles lying on the substrates by tailoring the concentration of the deposition solutions. This fabrication method can be extended to prepare other kinds of crystallized nanostructures of LnPO4 such as CePO4 and rare-earth-doped luminescent LaPO4. The formation of the single-crystalline nanoneedles under such a mild condition originates from the successive interfacial reaction of lanthanide and phosphate ions and the intrinsic anisotropic growth habit of hexagonal LnPO4.The present study is meaningful in developing new methodologies to fabricate single-crystal nanostructures deposited directly on solid substrates without the requirement of high reaction temperature and tedious procedures.