Multicolor Fluorescent Lead‐MOFs for White‐Light‐Emitting and Anticounterfeiting Applications

Abstract

The synergistic effect of rigid organic framework and soft lattice makes metal‐organic framework (MOF) luminescent materials more widely used. Herein, 2D lead‐MOFs are reported that produce white light through the coregulation of free excitons and self‐trapped excitons. The synthesized BIF‐142‐Cl shows outstanding white‐light emission with the CIE color coordinates of (0.312, 0.335) close to pure white light, the excellent color rendering index (CRI) of 90.4, and the gentle correlation color temperature (CCT) of 5364 K. Meanwhile, the multicolor emission from blue to white light can be adjusted by changing the excitation wavelength. Furthermore, photophysical studies confirm that the strong electronic phonon coupling in the excited state of lead halide polyhedrons is directly responsible for the generation of self‐trapped excitons. This synthetic strategy of introducing tunable dual emission centers not only offers a prospect for the development of solid‐state lighting materials but also widens the path to the fields of anticounterfeiting, display media, and information identification.

Nanoporous Organic Frameworks as Light-Emitting Diodes: A Review

“…− as the ligand and lead halide (PbN 4 X) as the secondary building unit. 72 Figure 6b displays the tunable emission exhibited by BIF-142-Cl upon varying the excitation wavelength from 310 to 350 nm. Upon photoexcitation at 350 nm, BIF-142-Cl exhibits white emission and is hence used to fabricate a WLED prototype.…”

“…The PLQY of BIF-142-Cl (16−18%) is around 10-fold higher than those of BIF-142-Br (2.8%) and BIF-142-I (0.8%). 72 This difference can be attributed to the increased crystal self-absorption upon a decrease in the Stokes shift, the decreased lead halide (Pb−X) bond strength for larger halogens, and the decreased quantum yields due to increased thermal vibration. 72 In a similar study, an europium-codoped barium imidazolate framework, namely, 3 [Ba(Im) 2 ]:Eu 2+ , was prepared.…”

“…72 This difference can be attributed to the increased crystal self-absorption upon a decrease in the Stokes shift, the decreased lead halide (Pb−X) bond strength for larger halogens, and the decreased quantum yields due to increased thermal vibration. 72 In a similar study, an europium-codoped barium imidazolate framework, namely, 3 [Ba(Im) 2 ]:Eu 2+ , was prepared. 73 The MOF exhibits light emission in the yellow region with a peak at 560 nm and CIE coordinates of (0.433, 0.516) upon excitation by UV light (Figure 6c).…”

“…(b) Emission spectra of BIF-142-Cl at different excitation wavelengths. Reproduced with permission from ref . Copyright 2023 Wiley-VCH.…”

Assembly of One-, Two-, and Three-Dimensional Cu(I)-Based Coordination Frameworks for Tunable White Light Emission and Effective Fluorescence Sensing

“…Among luminescent materials, white-light-emitting solids have been considered as the most attractive candidate in the solid-state display, owing to their long operation lifetimes and effective energy saving. − Typically, white-light emission could be achieved by a single-component luminescence or a multicomponent mixed emission. − With respect to multicomponent luminescence, a mixture of red, green, and blue emitters or a mixture of yellow and blue luminophores in appropriate proportions can accomplish the white light emission. − Benefiting from the large number of yellow-emitting materials that have been constructed in recent years, there is a great feasibility to prepare white-light-emissive solids with good color rendering indexes once these luminescent species are combined with the blue phosphor. For the acquisition of yellow emission, several groups of rare-earth-based inorganic phosphors and organic luminescent solids have been constructed.…”