Construction of NaYF₄ Library for Morphology‐Controlled Multimodality Applications

Abstract Morphology and size of the nanoparticles are highly related to the properties; establishing a library to summarize the relationship between the morphology/size and property is very helpful for associated applications. However, the NaYF₄ library and thus the correlation between the morphology and property are still absent. Here NaYF₄ library is presented and their morphologies and structures are illustrated at atomic scale for the first time. How about the crystal formation affects the morphology is further used to guide the property. Through rational doping, upconversion luminescence, magnetic resonance (MR) and computed tomography are investigated with the nanoprisms, nanoflowers, and nanoplates as models to reveal the effect of the size and morphology. The difference of the properties provides strong evidence on the importance of the library. In particular, the “imperfect structure” of nanoflower is observed on atomic scale and enhances the MR response. The different upconversion intensity ratio for the emissions at 475 and 693 nm is observed from doped NaYF₄ with different morphology. Thus, controllable fabrication of NaYF₄ with desired morphology is indispensable to achieve the optimal properties as the guidance on how to choose matrix from the library to meet the specific applications.