Jiancan Yu

A Luminescent Mixed-Lanthanide Metal–Organic Framework Thermometer

A luminescent mixed lanthanide metal-organic framework approach has been realized to explore luminescent thermometers. The targeted self-referencing luminescent thermometer Eu(0.0069)Tb(0.9931)-DMBDC (DMBDC = 2, 5-dimethoxy-1, 4-benzenedicarboxylate) based on two emissions of Tb(3+) at 545 nm and Eu(3+) at 613 nm is not only more robust, reliable, and instantaneous but also has higher sensitivity than the parent MOF Tb-DMBDC based on one emission at a wide range from 10 to 300 K.

Dual-emitting MOF⊃dye composite for ratiometric temperature sensing.

A strategy to achieve a ratiometric thermometer by encapsulating luminescent perylene dye into the pores of a europium metal-organic framework (MOF) is developed. The resulting MOF⊃dye thermometer exhibits highly temperature-dependent luminescence intensity ratio over the physiological temperature range, with a maximum sensitivity of 1.28% °C(-1) at 20 °C.

Second‐Order Nonlinear Optical Activity Induced by Ordered Dipolar Chromophores Confined in the Pores of an Anionic Metal–Organic Framework

Frequency doubling: A strategy for incorporating dipolar organic chromophores into the one-dimensional channels of an anionic metal-organic framework (MOF) has been developed to generate highly active nonlinear optical materials (see picture). The resulting MOF material shows a second-harmonic generation intensity of 18.3 versus α quartz.

Confinement of pyridinium hemicyanine dye within an anionic metal-organic framework for two-photon-pumped lasing

Two-photon-pumped dye lasers are very important because of their applications in wavelength up-conversion, optical data storage, biological imaging and photodynamic therapy. Such lasers are very difficult to realize in the solid state because of the aggregation-caused quenching. Here we demonstrate a new two-photon-pumped micro-laser by encapsulating the cationic pyridinium hemicyanine dye into an anionic metal-organic framework (MOF). The resultant MOF⊃dye composite exhibits significant two-photon fluorescence because of the large absorption cross-section and the encapsulation-enhanced luminescent efficiency of the dye. Furthermore, the well-faceted MOF crystal serves as a natural Fabry–Perot resonance cavity, leading to lasing around 640 nm when pumped with a 1064-nm pulse laser. This strategy not only combines the crystalline benefit of MOFs and luminescent behaviour of organic dyes but also creates a new synergistic two-photon-pumped lasing functionality, opening a new avenue for the future creation of solid-state photonic materials and devices.

Luminescent Metal–Organic Framework Films As Highly Sensitive and Fast-Response Oxygen Sensors

Luminescent metal-organic framework films, CPM-5⊃Tb(3+) and MIL-100(In)⊃Tb(3+), have been constructed by postfunctionalization of two porous indium-organic frameworks with different structures, respectively. The MIL-100(In)⊃Tb(3+) film shows high oxygen sensitivity (KSV = 7.59) and short response/recovery time (6 s/53 s).

Two-photon responsive metal-organic framework

Two-photon processing presents a facile means to tailor the properties of materials in three-dimensions. A two-photon responsive metal-organic framework (MOF) has been realized through the incorporation of a photoactive linker into a MOF via a multivariate strategy. The resulting MOF exhibits a significant one-photon and two-photon excited fluorescence change in response to UV light and infrared femtosecond laser, enabling spatial modulation of the fluorescence property of the MOF. It thus demonstrates the capacity of two-photon patterning and imaging inside the crystal, and the formation of three-dimensional two-photon excited fluorescent structure in a high resolution.

A Low Cytotoxic Cationic Metal–Organic Framework Carrier for Controllable Drug Release

A positively charged porous drug carrier MOF-74-Fe(III) (1, MOF = metal-organic framework), which could not be directly synthesized using ferric salts, was prepared through the oxidation of the neutral crystal MOF-74-Fe(II). This cationic host material exhibits very low cytotoxicity upon PC12 cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium (MTT) assay and high drug loading capacity of ibuprofen anions (∼15.9 wt %) through ion exchange and salt penetration procedures. Controlled by anion exchange, two mechanisms were involved in the drug release process with different drug delivery rates due to the presence of coordinated or free ibuprofen anions, making the administration of drug release more flexible.

A porous metal–organic framework with –COOH groups for highly efficient pollutant removal

A new metal-organic framework with -COOH groups has been realized and demonstrates strong interactions with methylene blue and thus the complete removal of methylene blue from aqueous solution.

Polarized three-photon-pumped laser in a single MOF microcrystal

Higher order multiphoton-pumped polarized lasers have fundamental technological importance. Although they can be used to in vivo imaging, their application has yet to be realized. Here we show the first polarized three-photon-pumped (3PP) microcavity laser in a single host–guest composite metal–organic framework (MOF) crystal, via a controllable in situ self-assembly strategy. The highly oriented assembly of dye molecules within the MOF provides an opportunity to achieve 3PP lasing with a low lasing threshold and a very high-quality factor on excitation. Furthermore, the 3PP lasing generated from composite MOF is perfectly polarized. These findings may eventually open up a new route to the exploitation of multiphoton-pumped solid-state laser in single MOF microcrystal (or nanocrystal) for future optoelectronic and biomedical applications.

Enhancement of nonlinear optical activity in new six-branched dendritic dipolar chromophore

A new six-branched chromophore GGQ1 is designed and synthesized via the incorporation of an FTC-type chromophore 1 with phenyl glycerol ester. The six-branched chromophore GGQ1 shows a large molecular weight of 3834 Daltons and can directly form thin films with quite high active chromophore loading density. For comparison, guest–host doped polymer films are fabricated by doping chromophore 1 and BF1 into poly(4-vinylphenol). All of these doped films show a saturated trend in second harmonic generation coefficient (d33) and a maximum d33 value between 50–70 pm V−1 around the doping concentration of 25 wt%, due to the strong interchromophore electrostatic interactions. In contrast, GGQ1 films display a d33 value of 192 pm V−1. The results indicate that the six-branched chromophore could efficiently reduce the interchromophore electrostatic interactions and enhance the macroscopic optical nonlinearity, showing promise for applications in nonlinear optical (NLO) materials.