Rare-Earth/Inorganic/Organic Polymeric Hybrid Materials: Molecular Assembly, Regular Microstructure and Photoluminescence

Photoluminescent and Chromic Nanomaterials for Anticounterfeiting Technologies: Recent Advances and Future Challenges

Counterfeiting and inverse engineering of security and confidential documents, such as banknotes, passports, national cards, certificates, and valuable products, has significantly been increased, which is a major challenge for governments, companies, and customers. From recent global reports published in 2017, the counterfeiting market was evaluated to be $107.26 billion in 2016 and forecasted to reach $206.57 billion by 2021 at a compound annual growth rate of 14.0%. Development of anticounterfeiting and authentication technologies with multilevel securities is a powerful solution to overcome this challenge. Stimuli-chromic (photochromic, hydrochromic, and thermochromic) and photoluminescent (fluorescent and phosphorescent) compounds are the most significant and applicable materials for development of complex anticounterfeiting inks with a high-security level and fast authentication. Highly efficient anticounterfeiting and authentication technologies have been developed to reach high security and efficiency. Applicable materials for anticounterfeiting applications are generally based on photochromic and photoluminescent compounds, for which hydrochromic and thermochromic materials have extensively been used in recent decades. A wide range of materials, such as organic and inorganic metal complexes, polymer nanoparticles, quantum dots, polymer dots, carbon dots, upconverting nanoparticles, and supramolecular structures, could display all of these phenomena depending on their physical and chemical characteristics. The polymeric anticounterfeiting inks have recently received significant attention because of their high stability for printing on confidential documents. In addition, the printing technologies including hand-writing, stamping, inkjet printing, screen printing, and anticounterfeiting labels are discussed for introduction of the most efficient methods for application of different anticounterfeiting inks. This review would help scientists to design and develop the most applicable encryption, authentication, and anticounterfeiting technologies with high security, fast detection, and potential applications in security marking and information encryption on various substrates.

Robust and Reversible Vapoluminescent Organometallic Copper Polymers

Emissive organometallic polymers are an important class of functional materials characterized by the combined photoluminescent features of organometallic molecules and the properties of traditional polymers. In this work, the emissive organometallic complex, [CuBr(PPh₃ )₂ (4-methylpyridine)], is successfully, mechanically ground into a random copolymer built on 4-(diphenylphosphino)styrene (DPVP) and n-butyl acrylate (BA) monomers. The resultant hybrid materials successfully inherit the emissive centers, and are significantly reinforced by the copper complexes as chemical crosslinkers in the polymeric continuum. These organometallic polymers are also proved to have excellent vapoluminescent properties, exhibiting unique responses to many organic solvent vapors, reflecting their rapid loss and recovery of photoluminescence. Mechanically robust and flexible films prepared with these organometallic Cu(I)-polymers are tested as recoverable sensors for hazardous volatile chemical compounds (VOCs) such as toluene, acetone, chloroform, and dichloromethane, and the low limits of detection (LOD) can reach as low as 1 × 10^-3 -8 × 10^-3 mg L^-1 (0.2-3.3 ppmV, parts per million-volume) for various VOCs. This work sheds lights on the design and fabrication of organometallic polymers for advanced applications.

Markedly enhanced up-conversion luminescence by combining IR-808 dye sensitization and core–shell–shell structures

The up-conversion emission of core–shell–shell structured nanoparticles has been greatly enhanced by IR-808 dye sensitization of 808 nm photons.

Lanthanide complex inside–outside double functionalized zeolite A hybrid materials for luminescence sensing

Double functionalization assembled hybrids exhibit luminescence in the visible/NIR region and among which [DBM-Yb-ZA]–NTASi-Eu shows high sensing selectivity for Fe³⁺.

Highly effective chemosensor of a luminescent silica@lanthanide complex@MOF heterostructured composite for metal ion sensing

A highly selective and sensitive heterogeneous sensor to detect Cu²⁺ in aqueous solution has good fluorescence stability, low detection limit and broad linear range making it a potential chemosensor for Cu²⁺ in environmental systems.

Multi-component assembly and luminescence tuning of lanthanide hybrids based with both zeolite L/A and SBA-15 through two organically grafted linkers

Novel luminescent micro–mesoporous multi-component lanthanide hybrid materials are prepared by assembling both functionalized zeolite A/L and modified SBA-15 through two organically grafted silane linkers.

Core–shell structured Gd2O3:Ln@mSiO2 hollow nanospheres: synthesis, photoluminescence and drug release properties

Core–shell structured Gd₂O₃:Ln@mSiO₂ hollow microspheres with an interesting double-shell and mesoporous structure have been fabricated. The luminescent composite shows obvious drug storage and release properties.

Novel photofunctional hybrid materials (alumina and titania) functionalized with both MOF and lanthanide complexes through coordination bonds

Multi-component sol–gel derived alumina and titania hybrid materials are assembled by the functionalization of both lanthanide complexes and a special metal organic framework compound: Al-MIL-53-COOH through coordination bonds. Multi-color luminescence and white colored light can be tuned by controlling the different units in the hybrid system.

Hybrid polymer thin films with a lanthanide–zeolite A host–guest system: coordination bonding assembly and photo-integration

Three tricolor luminous materials based on novel transparent hybrid films of polymer–lanthanide–zeolite A were assembled. The white light emission from the tricolor luminous materials can be tuned easily by adjusting the different concentrations of the doped ions and the excitation wavelength.