Tailoring photoluminescence and multifunctionalities of lanthanide coordination complexes employing ligand-controlled aggregation states

Abstract

Developing lanthanide(III) ion (Ln³⁺) coordination complexes to mimic sunlight and achieve dynamic anti-counterfeiting is cutting-edge research, but it remains a significant challenge for luminescence color tuning and advanced information handling. Herein, a precisely designed ligand (TL) displays controllable monomers and excimers in different environments, resulting in the colorimetric properties of Ln³⁺ complexes (TL-Eu/Tb). When the sensitizer resides in the dimeric state, only TL-Eu gives strong luminescence, including outstanding WLE. Instead, in the monomeric state, TL-Eu/Tb emits red/green luminescence, and Eu³⁺/Tb³⁺ co-doped films demonstrate tunable luminescence properties and satisfactory WLE (CIE coordinates of (0.33, 0.33)) can be obtained from a customized film with a 1 : 9 (Eu³⁺/Tb³⁺) molar ratio. Interestingly, the resulting WLE materials could be utilized in the preparation of white light-emitting-diodes (WLEDs) with superior color quality and have shown potential for advanced anti-counterfeiting applications due to their multi-stimuli responsiveness. This work provides a promising strategy for fabricating smart materials that utilize the controllable aggregation of sensitized ligands.