Chiral Lanthanide Complex Isomers Enable Ultra-High-Brightness Narrowband X-Ray Scintillation and Lysosome Optical Imaging via Aggregation and Dual-Antenna Effects.

Narrowband X-ray scintillators with high light yield (LY) are critical for high-performance medical imaging, yet existing lanthanide-based systems still face challenges in emission efficiency and color purity. Herein, we report a pair of chiral lanthanide complex isomers (GXU-1/2) with a full-width at half-maximum (FWHM) of only 8 nm and the highest LY constructed via the synergism of aggregation-enhanced antenna effect from aggregation-induced emission luminogens (AIEgens) and secondary antenna effect from rigid auxiliary ligands. Two pairs of chiral lanthanide complex isomers GXU-1/2 and GXU-3/4 both showed significant aggregation-enhanced antenna effects, exhibiting bright lysosome optical imaging effects. This dual-antenna strategy endows the materials with efficient energy transfer to Eu(III), confirmed by femtosecond transient absorption spectroscopy. GXU-1 achieves an ultrahigh LY of 70,199 photons MeV-1, an extremely low detection limit of 52.52 nGy·s-1 (over 105-fold lower than clinical diagnostic standard (5.5 μGy/s)), and an ultranarrow full-width at half-maximum of only 8 nm, with red emission purity closely matching the BT.2020 standard. This work offers a general route for high-performance lanthanide X-ray scintillators.