Emission Color‐Tunable Lanthanide Metal‐Organic Frameworks for One‐/Two‐Photon Excited Fluorescence and X‐Ray Scintillation
Peng‐Kun Wang, Bao‐Yi Li, Shuai‐Liang Chen, Rui‐Xuan Qian, Zhao‐Xing Gao, Shuai‐Hua Wang, Fa‐Kun Zheng, Guo‐Cong GuoABSTRACT
The integration of two‐photon excited fluorescence and x‐ray scintillation into a single material entity is highly desirable for advanced multiscale medical and photonic applications. However, due to the lack of multiscale energy absorption capabilities or the uncontrollability of emission pathways, conventional luminescent materials are typically restricted to a single excitation modality. In this work, a series of luminescent color‐tunable lanthanide metal–organic frameworks (Ln‐MOFs) are synthesized by varying ratios of Ln 3+ ions with multimodal responsiveness. The strong x‐ray attenuation of heavy lanthanide centers and the large two‐photon absorption cross‐section of the NTB 3− ligands (H 3 NTB = 4,4',4''‐nitrilotribenzoic acid) synergistically enable across‐scale energy harvesting. Crucially, the suitably matched triplet state of the H 3 NTB ligand acts as a universal bridge, successfully converging the distinct initial excitations (one‐photon, two‐photon, and x‐ray) into an identical energy transfer pathway to produce highly efficient lanthanide‐centered emissions. Driven by these highly efficient emissions, the fabricated NTB‐Tb‐screen and NTB‐Eu‐screen films deliver exceptional x‐ray imaging spatial resolutions of 19.7 and 7.4 lp/mm, respectively.