Achieving high-efficiency photoluminescence in trivalent lanthanides(Ln^(3+))requires precise crystalfield perturbation to overcome parity-forbidden 4f-transitions and suppress nonradiative decay.However,realizing suc...Achieving high-efficiency photoluminescence in trivalent lanthanides(Ln^(3+))requires precise crystalfield perturbation to overcome parity-forbidden 4f-transitions and suppress nonradiative decay.However,realizing such control remains challenging,even in well-optimized Ln^(3+) -doped nanocrystals.Here,by exploiting the atomically precise structure of metal nanoclusters,we demonstrate symmetry engineering in the Eu_(2)Ti_(4) nanoclusters through stepwise ligand substitution(BA/Phen→FBA/Phen→FBA/Bpy.BA:benzoicacid;Phen:1,10-phenanthroline;FBA:p-fluorobenzoicacid;Bpy:2,2'-bipyridine).The incorporation of FBA effectively suppresses nonradiative relaxation,while the flexible Bpy ligand induces symmetry reduction from D_(2d) to C_(2v) through coordination modulation,yielding a high photoluminescence quantum yield(PLQY)of 91.2%in the Ln^(3+) cluster systems.The transient-absorption,Judd-Ofelt theory,crystal-field analysis,and temperature-dependent photophysical studies elucidated the underlying modulation mechanisms.Furthermore,these clusters exhibit promising potential for optoelectronic applications,offering a new design strategy for high-performance luminescent materials.展开更多
基金Project supported by the National Key Research and Development Program of China(2024YFE0206100)the National Natural Science Foundation of China(T2325015,U21A2068,12174151)。
文摘Achieving high-efficiency photoluminescence in trivalent lanthanides(Ln^(3+))requires precise crystalfield perturbation to overcome parity-forbidden 4f-transitions and suppress nonradiative decay.However,realizing such control remains challenging,even in well-optimized Ln^(3+) -doped nanocrystals.Here,by exploiting the atomically precise structure of metal nanoclusters,we demonstrate symmetry engineering in the Eu_(2)Ti_(4) nanoclusters through stepwise ligand substitution(BA/Phen→FBA/Phen→FBA/Bpy.BA:benzoicacid;Phen:1,10-phenanthroline;FBA:p-fluorobenzoicacid;Bpy:2,2'-bipyridine).The incorporation of FBA effectively suppresses nonradiative relaxation,while the flexible Bpy ligand induces symmetry reduction from D_(2d) to C_(2v) through coordination modulation,yielding a high photoluminescence quantum yield(PLQY)of 91.2%in the Ln^(3+) cluster systems.The transient-absorption,Judd-Ofelt theory,crystal-field analysis,and temperature-dependent photophysical studies elucidated the underlying modulation mechanisms.Furthermore,these clusters exhibit promising potential for optoelectronic applications,offering a new design strategy for high-performance luminescent materials.
