Luminescence Modulation in Boron‐Cluster‐Based Luminogens via Boron Isotope Effects

Abstract Recent advances in luminescent materials highlight the significant impact of hydrogen isotope effects on improving optoelectronic properties. However, the research on the influence of the boron isotope effects on photophysical properties remains underdeveloped. This study focused on exploring the boron isotope effects in boron‐cluster‐based luminogens. In doing so, we designed and synthesized carborane‐based luminogens containing 98 % 10 B and 95 % 11 B, respectively, and observed distinct photophysical behaviors. Compared to the 10 B‐enriched luminogens, the 11 B‐enriched counterparts can significantly enhance luminescence efficiency, prolong emission lifetime, and reduce full‐width at half‐maximum. Additionally, increased thermal stability, redshifted B−H vibrations, and a fourfold enhanced electrochemiluminescence intensity have also been observed. On the other hand, the biological assessments of a 10 B‐enriched luminogen reveals low cytotoxicity, high boron uptake, and excellent fluorescence imaging capability, indicating the potential application in boron neutron capture therapy (BNCT). This work presents the first comprehensive exploration on the boron isotope effects in boron clusters, and provides valuable insights into the rational design of organic luminogens for advanced optoelectronic and biomedical applications.