Polarized Emission of Lanthanide Metal-Organic Framework (Ln-MOF) Crystals for High-Capacity Photonic Barcodes

Photonic barcodes hold great promise for applications in information storage and data encryption. However, the spectroscopic encoding of lanthanide-based photonic barcodes reported thus far is exclusively manipulated by sophisticated external stimuli or spatially resolved lanthanide heterostructures, and still suffers from small coding space and low coding capacity. Herein, a facile approach to design high-capacity photonic barcodes through manipulating the polarized emission of Eu3+ metal-organic framework is proposed. Thanks to the highly anisotropic crystal structure and low-symmetry energy level splitting of Eu3+, the large degree of polarization (approximate to 0.96) enables not only color-tunable emission but also abundant well-resolved sub-barcodes. Such polarization-sensitive emission of the crystals provides a smart encoding strategy to realize polarization-covert sub-barcodes, which can be further integrated into a large coding library of photonic barcodes toward high-capacity data storage and advanced anti-counterfeiting applications.