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Host Sensitized Lanthanide Photoluminescence from Post-synthetically Modified Semiconductor Nanoparticles Depends on Reactant Identity
摘要： This work investigates the photoluminescence characteristics where cadmium selenide (CdSe) and zinc sulfide (ZnS) nanoparticles are treated post-synthetically by the trivalent lanthanide cations (Ln3+) [Ln = Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb] separately to form either CdSe/Ln or ZnS/Ln nanoparticles. Host sensitized Ln3+ emission was found to be present only in CdSe/Eu, CdSe/Tb, ZnS/Eu, ZnS/Tb and ZnS/Yb nanoparticles. In all the cases tuning of emission of the nanoparticles has been observed, irrespective of the presence or absence of host sensitization. The elemental compositions of CdSe and ZnS nanoparticles upon post-synthetic treatment show a remarkable difference. Incorporation of lanthanides in the nanoparticles is evident with significant alteration in the anionic content, and complete cation exchange of either Cd2+ or Zn2+ by Ln3+ has not been detected; as evaluated from energy dispersive X-ray spectroscopy. Further evaluation on this comes from considering thermodynamic parameters of inter cation interaction. In cases where the host sensitized Ln3+ emission have been observed, luminescence lifetime measurements reveal significant protection of Ln3+ in the nanoparticles. Noticeable difference in photophysical properties for a given Ln3+ has been realized in the two hosts. The photophysical observations have been rationalized using (i) charge trapping mediated host sensitized dopant emission, (ii) autoionization of excited electrons, and (iii) environment induced photoluminescence quenching. The post-synthetic modification discussed in the present work provides an easy and less synthetically demanding room temperature based protocol to avail lanthanide incorporated (doped) semiconductor nanoparticles that can potentially use the unique emission properties of the lanthanide cations.
关键词： Semiconductor Nanoparticles,Host Sensitization,Trivalent Lanthanides,Photoluminescence,Post-synthetic Modification
更新于2025-09-23 15:23:52
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Post-synthetic platinum complex modification of a triazine based metal organic frameworks for enhanced photocatalytic H2 evolution
摘要： A triazine-based MOFs [PCN-9(Co)] was synthesized and its photoelectrical, photophysical properties were studied. As a new photocatalyst, PCN-9(Co) displays photocatalytic hydrogen evolution from water under UV–Visible light irradiation. With the introduction of platinum complex, PCN-9-Pt was obtained and platinum complex was believed to coordinate with the N in triazine. The H2 evolution rate of PCN-9-Pt is greatly improved, about 6.8 times higher than that of PCN-9(Co). The reason is due to the fact that platinum complex plays an important role in improving the separation efficiency of photogenerated charge carriers, as verified by PL and EIS results. This result provides a new kind of idea of modifying MOFs materials with molecular complex to improve the photocatalytic activity.
关键词： Post-synthetic,Platinum complex,Photocatalysis,Triazine-based MOFs
更新于2025-09-23 15:22:29
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Post-Synthetic Ligand Exchange of Metal Organic Framework for Photodynamic Therapy
摘要： Attributed to the large pore size and excellent stability, the metal organic framework (MOF) NU-1000, which is formed by the coordination of Zr cluster and 1,3,6,8-tetrakis(p-benzoicacid)pyrene (H4TBAPy) ligand, has been widely studied in the catalysis research field, however, only a few reports about the biomedical application of NU-1000 could be found in the open literature. In this study, a functional ligand, tetrakis(4-carboxyphenyl)porphyrin (TCPP) was introduced into NU-1000 via post-synthetic ligand exchange method, and the resultant mixed ligand MOF possesses excellent photodynamic effect. Finally, in vitro and in vivo assessment about the antitumor efficacy was investigated for the first time. It demonstrates the feasibility of TCPP substituted NU-1000 to be used for photodynamic therapy, and also provides an alternative approach to enrich the function of MOF for various applications via post-synthetic method.
关键词： Metal Organic Frameworks,ligand exchange,NU-1000,photodynamic therapy,post-synthetic modification
更新于2025-09-19 17:15:36
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2D Nanoplates and Scaled-up Bulk Polycrystals of Ruddlesden-Popper, Cs2PbI2Cl2 for Optoelectronic Applications
摘要： Two-dimensional (2D) layered Ruddlesden-Popper (RP) phases of halide perovskite offer exotic properties and interesting structure, which make them suitable candidate for solar photovoltaics, light emitting diode (LED) and photodetector applications. Simple and scaled-up synthesis, chemical transformations, doping and stability are the important steps towards the applications. Herein, all-inorganic RP phase of Cs2PbI2Cl2 was synthesized via a facile hot-injection method using benzoyl halides as halide sources. Different morphologies in the form of 2D nanoplates (NPLs) and small nanocrystals (NCs) were obtained by changing the concentration of capping agents (i.e., oleic acid and oleylamine) in solution. The excitonic absorption peak was appeared for NPLs and NCs, which is the characteristic feature of 2D halide perovskites. Further, the scalable quantity (~1 gm) of bulk powder and micron-sized particles of Cs2PbI2Cl2 were synthesized via liquid assisted mechanochemical grinding and anti-solvent method, respectively. We have performed post-synthetic chemical transformation to synthesize three-dimensional (3D) CsPbBr3 disk-shaped particles and zero-dimensional (0D) Cs4PbCl6 NCs from the pre-synthesized RP Cs2PbI2Cl2 NCs in solution and studied their optical properties. Finally, doping of Mn2+ was carried out in Cs2PbI2Cl2 NCs, which demonstrated typical feature of Mn2+ dopant emission along with host emission properties. Low-temperature (77 K) photoluminescence (PL) spectra reveal red-shifted and line-width broadening emission along with longer PL lifetime for both undoped and Mn-doped NCs compared to room temperature PL. Further, the temperature-dependent PL spectra and thermogravimetric analysis (TGA) revealed excellent thermal stability of Cs2PbI2Cl2. This work offers an insight for exploration of synthesis process, post-synthetic chemical transformation and dopant insertion in all-inorganic 2D RP perovskites, which is important step forward for application. Demonstrations of various simple synthesis of both the nano and bulk phases, structural transformation and detailed optical properties of doped and undoped RP perovskite halide nanostructures unfold innovative opportunities for applicability in optoelectronics such as in solar cell and photodetectors.
关键词： Synthesis,2D Halide Perovskites,Post-synthetic Transformation,Optical Properties,Mn-doping,Thermal Stability,Ruddlesden-Popper Phase
更新于2025-09-12 10:27:22
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Highly sensitive luminescent probe of aniline and trace water in organic solvents based on covalently modified lanthanide metal-organic frameworks
摘要： A novel europium functionalized MOF named Eu3+@UiO-66-NH2-IM is robustly synthesized via covalent PSM (post-synthetic modification). The ligand of matrix MOF is covalent modified via imidazole-2-carboxaldehyde after the UiO-66-NH2 is synthesized. The successful transformation of amino groups to imine groups is confirmed by FTIR analysis. The modified MOF named UiO-66-NH2-IM shows outstanding crystalline stability. After Eu3+ doped into UiO-66-NH2-IM, the as-prepared fluorescent MOF displays characteristic emission line of Eu3+. Discussion of the tunable emission color of the modified MOF is included and white light integration could be achieved through altering the ratio of Eu3+ doped into the MOF. What’s more, the luminescent transparent film based on Eu3+@UiO-66-NH2-IM can emit white light under proper excitation wavelength, which may be helpful to some potential applications in lighting. In addition, Eu3+@UiO-66-NH2-IM shows different emission response in water and organic solvents, and it is further developed into sensitive probe for the detection of water content in organic solvents (ethanol, DMF) with low detection limits ( 0.088%, and 0.054%, respectively) by utilizing its quenching behavior in water. Meanwhile, Eu3+@UiO-66-NH2-IM displays greatly selective and sensitive response for detecting aniline with a low detection limit (0.072%), a broad linear range (0-3.75%), and the signal of the detection is obvious which can be seen clearly under the irradiation of UV light.
关键词： Trace water,fluorescence probe,Zr-based metal-organic frameworks,covalen t post-synthetic modification,aniline
更新于2025-09-10 09:29:36
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Dimensional Impact of Metal-Organic Frameworks in Catalyzing Photo-Induced Hydrogen Evolution and Cyanosilylation Reactions
摘要： Metal-organic frameworks (MOFs) have been widely studied as heterogeneous catalysts. Compared to the MOFs with three dimensional (3D) topologies, two dimensional (2D) MOF nanosheets can allow facile access to the active sites on their external surface, thus having huge potentials in catalysis. Herein, we fabricate 2D MOF nanosheets, UiO-67-NS, as photocatalyst for H2 evolution reaction, and study their photocatalytic performance in relation to their 3D bulk counterparts (UiO-67). The UiO-67-NS exhibit an 84-fold increase in photocatalytic efficiency compared to UiO-67. Postsynthetic cation grafting of the UiO-67-NS with titanium leads to further enhancement in photocatalytic efficiency, giving a hydrogen evolution rate of up to 393 μmol g-1 h-1, which is 13-times higher than that of the non-grafting nanosheets under the same condition. Our results indicate that the 3D-to-2D dimensionality reduction can be a viable strategy for the development of MOFs as efficient photocatalysts. In addition, we have demonstrated that the improvement of catalytic performance based on the strategy of 3D-to-2D framework dimensionality reduction can be easily extended to heterogeneous cyanosilylation reaction.
关键词： Post-Synthetic Grafting,Metal-Organic Frameworks,Dimensional Impact,Photo-Induced Hydrogen Evolution,Metal-Organic Nanosheets
更新于2025-09-10 09:29:36