Double epitaxial growth of an ultra-stable Ga₂O₃/CsPbBr₃/CsGaSi₂O₆ heterostructure for multimodal applications

Constructing multicomponent heterostructures of lead halide perovskite nanocrystals is crucial for achieving highly stable and enhanced photoluminescence, as well as expanding optoelectronic applications. Herein, an MCM-41 molecular sieve-induced double epitaxial growth strategy is proposed to construct a ternary Ga₂O₃/CsPbBr₃/CsGaSi₂O₆ heterostructure. MCM-41 molecular sieves inhibit the decomposition of CsPbBr₃ nanocrystals (NCs) during the heating process and serve as a silicon source to generate another lattice matched CsGaSi₂O₆, while CsPbBr₃ NCs epitaxially grow on Ga₂O₃. Based on the lattice-matched epitaxial growth of CsPbBr₃ and CsGaSi₂O₆ on Ga₂O₃, the Ga₂O₃/CsPbBr₃/CsGaSi₂O₆ heterostructure exhibits significantly enhanced photoluminescence and the maximum photoluminescence quantum efficiency is 47.9%. Due to the dual surface defect passivation of Ga₂O₃ and CsGaSi₂O₆, the heterostructure exhibits high stability against ultraviolet (UV) irradiation, water, and heat. Based on the excellent stability and bright luminescence of the heterostructure, high-sensitivity temperature sensing with a maximum relative temperature sensitivity (S_r) of 6.4% at 363 K and fingerprint recognition have been achieved. Meanwhile, WLEDs equipped with the heterostructure achieved a high luminous efficiency of 68.4 lm W^-1. This work provides a simple and green approach for assembling lattice matched multicomponent perovskite heterostructures with enhanced photoluminescence and stability for multimodal applications.