High‐Entropy Lanthanide Metal‐Organic Frameworks as Multifunctional Porous Scintillators for Radiation Detection and Dual‐Mode Uranyl Sensing

Abstract Despite the burgeoning interest in high‐entropy materials (HEMs), their application as scintillators remains largely untapped. Herein, we report the first design of high‐entropy lanthanide‐based metal‐organic frameworks (HE‐Ln‐MOFs) incorporating five distinct lanthanides (La, Ce, Eu, Dy, and Er) as multifunctional porous scintillators. These materials exhibit stimulus‐responsive luminescence, enabling switchable white‐light emission and self‐calibrating thermometry. The HE‐Ln‐MOFs demonstrate a balanced optimization of key scintillation parameters, achieving a light yield of ∼17000 photons per MeV and a detection limit as low as 302 nGy air s −1 . X‐ray adsorption spectroscopy (XAS) and theoretical calculations reveal a unique multistep energy transfer (ET) pathway mediated by the Ce 3+ /Ce 4+ redox pair, presumably generated under high‐energy X‐ray irradiation. Furthermore, HE‐Ln‐MOFs demonstrate exceptional structural integrity, photostability, and a record uranyl adsorption capacity of 1532 mg g −1 , advantageous over their monometallic analogues. The synergy between ultrahigh adsorption, “turn‐on” photoluminescence (PL), and intense scintillating signal output portends unprecedented dual‐mode, on‐site detection of radionuclides in aqueous environments. This work establishes HE‐Ln‐MOFs as a promising platform for next‐generation porous scintillators in advanced radiation detection technologies.