Xiao-Gang Yang

3D Ag-MOF shows low luminescence losses of 5.91% relative to room temperature at 150 °C.

Two complexes, [(BrPhen)PbCl2] (1) and [(BrPhen)2BiCl3] (2), were solvothermally assembled by utilizing 3,8-dibromo-1,10-phenanthroline (BrPhen). 1 suffers 36.9% luminescence quenching at 150 °C, while 2 maintains high thermal stability with just 8.2% emission loss. The anti-TQ performance of 2 is comparable to those of several reported inorganic luminescent materials. In addition, phosphor-converted LED devices were fabricated, which exhibit stable light emission under high-power operation.

Pb(II)-based complexes have garnered widespread research interest for solid-state lighting and display devices by virtue of their unique structural tunability and appealing photophysical properties. Nevertheless, luminescence thermal quenching remains a critical bottleneck limiting their practical deployment. Herein, two coordination polymers [Pb(2,2'-bipy)Cl2] (1) and [Pb(4,4'-bipy)Cl2] (2) were hydrothermally synthesized using 2,2'-bipyridine (2,2'-bipy) and 4,4'-bipyridine (4,4'-bipy) ligands. Both complexes show excellent acid–base stability over pH 3–11 and maintain stability after 30 days of water immersion. Varied Pb(II) coordination geometries lead to divergent band gaps and thermal quenching behaviors: the yellow emission of 1 possesses only an 8.34 % loss of emission intensity at 150 °C, whereas the green emission of 2 undergoes 77.1 % luminescence quenching under the same conditions. The anti-thermal quenching performance of 1 rivals many reported inorganic luminescent materials. A proof-of-concept phosphor-converted white LED was fabricated based on the superior luminescence of 1. The device achieves a CRI of 87.3, CIE coordinates (0.301, 0.344), CCT of 6318 K, and stable long-term operation (10 h) under high-power conditions, revealing its promising prospects for high-quality white-light illumination.

Developing thermosensing materials that support synchronous temperature quantification via luminescence intensity and emission wavelength over an extensive temperature range remains highly sought-after. Herein, one anthracene-based MOF [Zn(ADA)(2,2'-bipy)] (1) was synthesized using 3,3-(anthracene-9,10-diyl)diacrylic acid (H2ADA) as luminescent center, 2,2'-bipyridine (2,2'-bipy) as electron-acceptor. Complex 1 was characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction, which revealed a 1D polymer chain and further assembled into a 3D supramolecular architecture via hydrogen bonding. This complex shows a narrow-band green emission (λem = 490 nm, FWHM = 58 nm). Its photophysical process was investigated via density functional theory calculations. Temperature-dependent photoluminescence measurements demonstrate that the complex exhibits high luminescent sensitivity (0.41% K-1) and thermochromic in a broad temperature range of 25 – 230 °C.

Diverse coordination geometries of Zn(II) and Cd(II) give rise to distinct halogen bonding interactions and spatial arrangement of the 3,8-dibromophenanthroline luminescent center in two MOFs. The two materials exhibit distinct thermal quenching degrees of 38.9% and 11.9% at 150 °C. The Cd-MOF presents outstanding anti-thermal-quenching performance superior to many reported inorganic phosphors. Assembled phosphor-converted LED devices confirm their great potential for solid-state lighting.

The development of luminescent thermometers synchronously exhibiting high sensitivity and stability in a wide temperature range poses significant challenges. Herein, a novel {Pb ₆ } wheels based metal‐organic framework (MOF) formulated as [Pb(pyIPA)]·1.2H ₂ O ( Pb‐pyIPA, H ₂ pyIPA = 4‐(pyridin‐4‐yl)isophthalic acid) was synthesized via a solvothermal procedure. The Pb‐pyIPA MOF possesses a new (4,4)‐connected zeolite‐type structure with dynamic nanotubes modified by {Pb ₆ } wheels. It shows intensive green emission with a long lifetime of 180 ns and maintains 98.5% of its initial emission intensity after immersion in water for 90 days. By contrast, temperature‐dependent photoluminescence explorations demonstrate that the emission intensity and lifetime decreased linearly over the temperature range of 298–423 K, achieving a maximal thermal quenching of 93%, relative sensitivity (S _r ) of 1.03% K ⁻¹ (intensity‐based) and 0.97% K ⁻¹ (lifetime‐based). These values surpass those of most reported MOFs and commercial inorganic phosphors. Mechanism of high temperature sensitivity was explored by the combination of single crystal X‐ray diffraction analysis and density functional theory calculations. The diameter of {Pb ₆ } wheel can be reversibly tuned under the stimulation of external temperature (298–400 K), leading to a significant decrease in the electron cloud distribution around the {Pb ₆ } wheels. Thus, both the emission intensity and lifetime can be vastly affected by the dynamic structural transformation. In addition, the stability and reusability of Pb‐pyIPA were also investigated, which can maintain high sensitivity under reversible temperature variations between 298 and 423 K for 5 cycles. This study offers a new perspective for balancing the contradiction between high sensitivity and stability of luminescent thermometers in a wide operational temperature range.

In this study, Ag@Cd-MOF composite hydrogel was successfully constructed via reductive doping and free radical polymerization technology. Structural characterization confirmed that Ag@Cd-MOF particles were uniformly dispersed in the hydrogel network, and the crystal structure of Cd-MOF remained intact. For fluorescent performance, the emission intensity of the composite hydrogel at 333 nm was enhanced by 89.1% compared with pure Cd-MOF. The fluorescence quenching efficiencies for cefixime (CEF), pyrimethanil (PTH), and 2,4-dinitrophenylhydrazine (2,4-DNP) reached 97.3%, 98.03%, and 93.1%, respectively, with corresponding detection limits of 0.12, 0.04, and 0.008 μM. Mechanism research indicated that the fluorescence quenching effect was mainly attributed to the synergistic effect of resonance energy transfer and competitive absorption. In the detection of CEF in milk samples, the spiked recovery rates ranged from 99.52% to 102.31% with relative standard deviations (RSD) of 0.72%-1.78%. Regarding antibacterial performance, the diameters of inhibition zones against three common pathogenic bacteria (Shigella flexneri, Shigella dysenteriae, and Staphylococcus aureus) were 22.7, 16.5, and 15.6 mm, respectively. The antibacterial rate remained above 74% after 72 hours, which was mainly due to the sustained bactericidal effect of Ag+ through the dual pathways of "membrane damage-intracellular metabolic interference". The material developed in this study, integrating efficient fluorescent detection and long-lasting antibacterial functions, provides a novel solution for food safety monitoring.

Pb-based organic-inorganic hybrid metal halides have attracted widespread attention due to their promising applications in solar cells, LEDs, and lasers. However, pressing thermal quenching concern continue to represent major unresolved challenges. Herein, by employing acridine (AD) organic chromophores to replace conventional inorganic luminescent centers, and substituting Pb2+ with Bi3+, a novel hybrid metal halide [(AD)BiCl₄] was synthesized under hydrothermal conditions. This phosphor retains 97.5% and 80.8% of its initial emission intensity after immersion in water for 60 days and heating at 150 °C, respectively. Its anti-thermal quenching performance is higher than majority of reported Pb-based hybrid metal halides and even exceeds several inorganic phosphors prepared under high-temperature (about 1000 °C) sintering process. Single crystal of this complex possesses a high electrical conductivity of 6.33 × 10-3 S m-1 and 1.12 ×10-2 S m-1 under dark and illuminated states, respectively. Meanwhile, a phosphor-converted white LED device was fabricated by directly coupling yellow phosphor with a commercial blue LED chip. The device exhibits a high color rendering index of 85.7, CIE coordinates of (0.328, 0.344), CCT of 6576 K, and stable long-term operation under high-power conditions. Therefore, this work provides novel perspectives for constructing Bi3+-based metal halide with suppressed thermal quenching for solid-state lighting applications.