Efficient Tb³⁺-to-Eu³⁺ energy transfer for colorimetric luminescence sensing

State-of-the-art Tb-to-Eu energy transfer (TEET) efficiency (>90%) under ultralow Eu³⁺ proportion (<6%) has been achieved in Eu/Tb bimetallic lanthanide coordination polymers (LnCPs). The yellow-light-emitting sample as sensor exhibits micromolar l-phenylalanine (l-Phe) in water and serum via obvious yellow-to-green luminometric behavior, meanwhile nanomolar-level detection limits are determined in terms of an updated Stern-Volmer equation with high selectivity and competitiveness. Excited-state inter-ligand photon transfer (ESILPT) greatly contributes to superior TEET property and outstanding luminometric behavior. This work opens a window for developing sensitive and stable visualization sensing, being of values on monitoring biochemical markers.