Excitation Wavelength‐Dependent Fluorescence of a Lanthanide Organic Metal Halide Cluster for Anti‐Counterfeiting Applications
Hongyuan Zhao, Qiujie Wang, Ziying Wen, Haibo Sun, Sujun Ji, Xuan Meng, Ruiling Zhang, Junke Jiang, Zhe Tang, Feng Liu
Abstract
Abstract The achievement of significant photoluminescence (PL) in lanthanide ions (Ln 3+ ) has primarily relied on host sensitization, where energy is transferred from the excited host material to the Ln 3+ ions. However, this luminous mechanism involves only one optical antenna, namely the host material, which limits the accessibility of excitation wavelength‐dependent (Ex‐De) PL. Consequently, the wider application of Ln 3+ ions in light‐emitting devices is hindered. In this study, we present an organic–inorganic compound, (DMA) 4 LnCl 7 (DMA + =[CH 3 NH 2 CH 3 ] + , Ln 3+ =Ce 3+ , Tb 3+ ), which serves as an independent host lattice material for efficient Ex‐De emission by doping it with trivalent antimony (Sb 3+ ). The pristine (DMA) 4 LnCl 7 compounds exhibit high luminescence, maintaining the characteristic sharp emission bands of Ln 3+ and demonstrating a high PL quantum yield of 90–100 %. Upon Sb 3+ doping, the compound exhibits noticeable Ex‐De emission with switchable colors. Through a detailed spectral study, we observe that the prominent energy transfer process observed in traditional host‐sensitized systems is absent in these materials. Instead, they exhibit two independent emission centers from Ln 3+ and Sb 3+ , each displaying distinct features in luminous color and radiative lifetime. These findings open up new possibilities for designing Ex‐De emitters based on Ln 3+ ions.