Ultra-stable panchromatic luminescent BaMoO₄/CsPbX₃ (X = Cl, Br, I) heterostructures by suppressing interfacial...

Constructing perovskite heterostructures with restricted interface charge transfer is crucial for improving stability and optoelectronic performance, as well as expanding multifunctional applications. Herein, a one-step solvent-free thermal assisted epitaxial growth strategy is proposed to construct BaMoO₄/CsPbX₃ (X = Cl, Br, I) heterostructures. Derived from the high lattice matching of 90.3 %-100 %, CsPbX₃ QDs were epitaxially grown in situ on the surface of the BaMoO₄ substrate. Compared with CsPbBr₃ QDs, the BaMoO₄/CsPbBr₃ heterostructure exhibited significantly improved photoluminescence and extended fluorescence lifetime, which is attributed to the surface defect passivation effect of MoO₄^2- ions on CsPbBr₃ QDs. Significantly, strongly bound Frenkel excitons in scheelite-type BaMoO₄ inhibit interfacial charge transfer in the heterostructures, thereby imparting ultra-stable full-color luminescence under exposure to radiation, solvents, and heating-cooling cycles. In addition, stable anti-counterfeiting labels have been achieved based on the BaMoO₄/CsPbX₃ heterostructures with blue, green, and red luminescence, which can stably emit light for a long time in air and various polar solvents. On the other hand, the white light-emitting diode (WLED) device equipped with green emitting BaMoO₄/CsPbBr₃ achieves a high luminous efficiency of 31.2 lm W^-1, a correlated color temperature (CCT) of 7586 K, and a wide color gamut of 100.0 % NTSC in the white light region. This work provides a simple solvent-free thermal synthesis method for assembling perovskite heterostructures with high stability and restricted interfacial charge transfer, which is crucial for developing multifunctional optical.