Interfacing inorganic halide perovskites with metal-organic frameworks: Color tunable emission, energy transfer, and advanced anti-counterfeiting application

This work presents an inorganic halide perovskite (CsPbBr₃) is interfaced with a europium metal-organic framework (Eu-MOF). The presence of characteristic absorption edge and band edge emission of CsPbBr₃ reveal a successful formation of CsPbBr₃@Eu-MOF hybrid. The bi-flower morphology of Eu-MOF has tetragonal structure with space group P4₃22. The conical part of the bi-flower consists of many squared rods of edge length 200 nm. The CsPbBr₃@Eu-MOF shows color-tunable emission under different excitation wavelengths whose CIE color coordinate covers the entire green to red region. The maximum luminous efficacy of the optical radiation achieved is 359 lm/W, and the maximum color purity is 94.4 %, which is significant for optical applications. Further for anti-counterfeiting application, a pattern “LMDD” is encrypted on four different substrates and the color change is captured under different excitation wavelengths. The results show that CsPbBr₃@Eu-MOF is highly suitable for encryption and decryption of security codes particularly on plastic surface.