Thermal- and Excitation-Dependent Photoluminescence and Radioluminescence in Hybrid Cu(I) Halides for Optical...

Emerging luminescence metal halides with thermal- and excitation-dependent (Ex-De) luminescence are highly desirable for multifunctional optoelectronic devices, yet this goal remains unrealized in low-dimensional systems. Herein, by manipulating excited-state structural deformability to fine-tune multiple triplet excitons, we present a hybrid Cu(I)-based halide of [4-APD]₃Cu₂Br₆·2Br with adjustable photoluminescence and radioluminescence properties. [4-APD]₃Cu₂Br₆·2Br demonstrates unusual Ex-De multicolor luminescence from blue, green to orange in the range of 80-300 K by breaking the limit of Kasha's rule, synchronously achieving pure white-light emission with ultra-high quantum yield. Furthermore, three emission bands show distinct temperature-dependent intensity and lifetime in a wide range of 80-400 K due to reversible energy transfer among different excited states. Leveraging this unique thermal-responsive luminescence, we fabricate multimodal luminescence ratiometric and lifetime thermometers with ultrahigh relative sensitivities of 13.14%·K^-1, surpassing most of metal halides-based luminescent thermometers. In addition, high-precision luminescence temperature sensing was successfully conducted with the lowest measurement deviation of 0.99%. The efficient broadband emission also delivers promising scintillation performance with high light yield (11 000 photons·MeV^-1), low detection limit (1.43 µGy_air·s^-1) and high-resolution X-ray imaging (14 lp mm^-1). This work provides a new strategy for the design of hybrid Cu(I) halide with adjustable luminescence performance for multifunctional optoelectronic applications.