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

Abstract

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.