Upconversion Luminescence Research Articles

Upconverting Luminescent MOF for Highly Sensitive Dual-Mode Recognition of Synthetic Dyes.

Lanthanide-based luminescent materials hold promise in sensing applications due to their distinct optical properties. Though advancements in lanthanide-based metal-organic frameworks (MOFs) have enhanced downshifting luminescence, achieving upconversion remains challenging. In this effort, we prepared upconverting ytterbium-doped europium MOFs (x%Yb3+-EuMOFs; x = 10, 20, and 30) via the solvothermal method using 2,6-naphthalenedicarboxylic acid (NDC) as an organic linker. Upconversion (UC) luminescence studies revealed that 30%Yb3+-EuMOF (MOF-3) rapidly detects malachite green (MG, a textile dye) and brilliant green (BG, a food colorant) with excellent sensitivity (λex = 980 nm). Notably, UC luminescence offers a lower detection limit (MG: 36.33 nM, BG: 287.9 nM) compared to the downconverting sensing approach (λex 270 nm), while the related dual-mode luminescence minimizes the risk of false positives from interfering ultraviolet-visible (UV-vis) light-absorbing substances. Upconversion quenching has been linked to the FRET process, with its luminescence assay accurately detecting MG in fish, water, and soil samples under 980 nm excitation (98-105% recovery).

Enhancing up-conversion luminescence in Yb/Er co-doped CsPbCl3 single crystals

The search for and fabrication of materials for the near-infrared range of the spectrum, including telecommunication windows, is an extremely important task in modern technology. This work presents the results of studies on the photoluminescence of CsPbCl3 single crystals with varying contents of ytterbium and erbium impurities, grown using the Bridgman method. The existence of electrically neutral Yb3+–VPb–Er3+ complexes within the crystal structure was confirmed. Resonant absorption of excitation radiation λ = 980 nm by Yb3+ ions reveals a three-step energy transfer channel from Yb3+ to Er3+ ions within a single complex. The estimated quantum yield of up-conversion luminescence at λ = 524 nm (0.02%) associated with erbium ions indicates the presence of electronic transitions to higher energy levels, with the possibility of subsequent emission within the third telecommunication window.

Ultrafast Room‐Temperature Synthesis of Yb3+/Er3+ Codoped K3ZrF7 Nanocrystals for Thermal Enhancement of Upconversion

AbstractLanthanide (Ln3+)‐doped upconversion nanocrystals (NCs) have attracted great attention due to their outstanding luminescent performance and wide applications in various fields. However, the preparation of most Ln3+‐doped NCs requires rigorous conditions such as high reaction temperature, long reaction time, strict anhydrous and oxygen‐free environment, and tedious post‐treatment process. Herein, sub‐100 nm Yb3+/Er3+ codoped K3ZrF7 octahedral NCs are prepared by an extremely simple coprecipitation method (10 s only at room temperature). The resulting NCs show excellent upconversion luminescence (UCL), significantly superior to both their conventional high‐temperature‐synthesized counterparts and the room‐temperature‐synthesized NaBiF4:Yb/Er controls. More importantly, abnormal thermally enhanced UCL over a temperature range from room temperature to 473 K is found in these K3ZrF7:Yb/Er NCs, making them promising candidates for ratiometric thermometry applications. By employing the luminescence intensity ratio between two non‐thermally coupled energy levels of Er3+, namely 4F9/2 and 2H11/2, these NCs display an extraordinarily high absolute sensitivity of 443.2% K−1 and a comparatively large relative sensitivity of 1.55% K−1 at room temperature. These results reveal that K3ZrF7:Yb/Er NCs can not only be facilely prepared via an ultrafast room‐temperature synthesis, but also hold great potential in various areas such as optical temperature sensing and biological applications.

Dual–resonance enhancement and polarization control of upconversion luminescence of NaYF4:Yb,Er nanoparticles on 2D metal gratings

In this work, we report enhancement and polarization control of multi–color (green/red) upconversion luminescence (UCL) of lanthanide–doped (NaYF4:Yb,Er) nanoparticles by dual–resonance modes of surface plasmons (SP) on two–dimensional (2D) metal gratings in orthogonal directions. Investigations are performed for the SP resonance modes to be tuned, by adjusting the grating periods, to match any one or two of the green–UCL, red–UCL and excitation wavelengths. It is shown that, for the upconversion nanoparticles (UCNPs) on the 2D gratings with both of the dual resonance modes matching the green–/red–UCL or excitation wavelength, enhancements of the UCLs are roughly doubled, compared with their one–dimensional (1D) counterparts. And when the dual resonance modes match the green– or red–UCL and the excitation wavelength, enhancements of the UCLs are further greatly improved, in spite that the resonance modes for the excitation and emission light are in orthogonal directions. As the emitted UCL photons are largely coupled with the dual SP resonance modes, the radiated green– and red–UCL light can be distinguished by their linear polarization states in orthogonal directions. It is also indicated that polarization of the excitation light can influence the polarization of the UCL light when coupled with the SP resonance modes.

Fluorescent Polymer Composites Based on Core-Shell NaYF4:Yb/Er@NaGdF4:Ce/Tb Structures for Temperature Monitoring and Anti-Counterfeiting Protection

Synthesis and detailed morphological, structural, and photophysical analysis were conducted on core@shell NaYF4:Yb/Er@NaGdF4:Ce/Tb nanoparticles (C/S NPs). It was found that the NaGdF4:Ce/Tb shell significantly reduces defects in the NaYF4:Yb/Er core, enhancing the emission resolution of Er3+ ions. These C/S NPs exhibit dual luminescence functionality: upconversion with a quantum yield of 0.19%, driven by energy transfer between Yb3+ and Er3+ ions, and downshifting luminescence with a remarkable quantum yield of 96%, attributed to the energy transfer between Ce3+ and Tb3+ ions. Polymer nanocomposites, polystyrene-C/S (PS-C/S), and polyvinyl acetate-C/S (PVA-C/S) were synthesized by co-dissolving the polymers and nanoparticles in chloroform, followed by the removal of chloroform. Thin films based on the PS-C/S composite exhibited upconversion luminescence, enabling spatial temperature measurements with a lateral resolution of 10 μm and an accuracy of 1.6 K on a non-uniformly heated sample. The PVA-C/S composite exhibited dual-mode luminescence (upconversion and downshifting), which was employed to create fluorescent images activated by either NIR or UV irradiation. Additionally, these images demonstrated high stability against alcohols, acetone, and alkaline aqueous solutions, offering new anti-counterfeiting measures.

Enhanced upconversion luminescence of Er/Tm for highly sensitive multi-mode optical nanothermometer

A novel class of Er3+/Tm3+/Yb3+ co-doped Sc4Zr3O12 nanocrystals have been successfully synthesized via a hydrothermal method. The enhanced green and red emissions of Er3+are achieved through the mediation of Tm3+. Decay curves and DFT calculations indicate this enhancement is due to the cross relaxation processes and narrowed bandgap. Based on the temperature-dependent upconversion characteristics, a multi-mode optical thermometer is developed using the fluorescence intensity ratio (FIR) technique of thermally coupled levels (TCLs) and non-thermally coupled levels (NTCLs), as well as the valley to peak ratio (VPR) technique. The absolute sensitivity (Sa) and relative sensitivity (Sr) derived from 1G4(b)/2H11/2 NTCLs reach as high as 11.84% K−1 and 1.89% K−1, respectively. Additionally, the optimal sensitivities occur at 303 K, perfectly aligning with the physiological temperature range. A comparison of different fitting models for NTCLs reveals that the exponential model offers the best performance for this system, with a correlation coefficient of 99.9%. This work provides new insights into upconversion enhancement of multi-emission centers and lays the theoretical and experimental foundation for developing high-sensitivity and high-precision optical nanothermometers.

Strong multi-mode upconversion luminescence of YbVO4: Er3+ phosphors for multimode optical thermometry

This study explored the multi-mode upconversion luminescence in YbVO4: Er3+ under a 980nm laser. The optimal doping concentration of Er3+ ions in YbVO4: Er3+ is 0.02. The phosphor exhibits green (527nm, 2H11/2→4I15/2 and 553nm, 4S3/2→4I15/2), red (654nm, 4F9/2→4I15/2) and near-infrared emissions (803nm, 4I9/2→4I15/2). A multi-mode temperature sensor of YbVO4: Er3+ was developed, featuring three temperature sensing modes based on the luminescent intensity ratio (LIR) of 2H11/2/4S3/2 thermally coupled level, as well as the LIR of 2H11/2/4F9/2 and 4S3/2/4I9/2 non-thermally coupled levels. Corresponding maximum relative sensitivities were determined to be 1.21% K−1 at 298K, 0.93% K−1 at 298K, and 0.33% K−1 at 473K, respectively. The phosphor demonstrates notable temperature sensitivity, highlighting its potential in optical temperature sensing. This study introduces an innovative platform for crafting multi-mode self-reference optical temperature sensors, presenting substantial advancements in the field.

Green and facile synthesis of multihydroxy NaYF4:Yb/Er upconversion nanoparticle using natural peach gum

A simple and effective method has been developed for synthesizing multihydroxy NaYF4:Yb/Er upconversion nanoparticle (UCNP) using natural peach gum (PG) via hydrothermal synthesis. Initially, PG binds to metal ions, followed by pyrolysis to form water-soluble PG polysaccharide (PGP) ligands that coat the surface of the UCNP. This coating imparts hydrophilicity and introduces numerous hydroxyl groups to the UCNP. The resulting UCNP, with diameters ranging from 100 to 200 nm, exhibit a mixed cubic-hexagonal crystalline structure and demonstrate good upconversion luminescence and low toxicity. Additionally, the surface hydroxyl groups facilitate conjugation with functional molecules, enhancing the potential for post-modification. This green, simple, and efficient approach offers a promising pathway for producing UCNP, opening new possibilities for various applications.

Three‐Photon Upconversion Luminescence of Gd2O2S: Ho3+, Er3+ for High‐Sensitivity FIR Thermometer and Multimode Anti‐Counterfeiting

AbstractThe performance control and multidimensional applications of upconversion phosphor have become the hotspot and difficulty in current research and application due to the complex luminescence mechanism. Based on the efficient Gd2O2S: Er3+ upconversion luminescence of 1550 nm excitation and design strategy for co‐doped materials, the multicolor (light green to red) and multifunctional upconversion phosphor Gd2O2S: Er3+, Ho3+ is successfully prepared. Benefiting from the clear mechanism of three‐photon upconversion and energy transfer after co‐doping, the novel applications of Gd2O2S: Er3+, Ho3+ can greatly be expanded. This phosphor can be well used as a fluorescence thermometer due to the higher sensitivity (2.46% K−1@170 K), wider temperature sensing range (170–267 K, Sr > 1% K−1), and greater color variation (Δx = 0.2416, Δy = 0.2483) relative to Gd2O2S: Er3+ and other same type of material. In addition, multiple patterns and encoded outputs are also effectively achieved by the combination of phosphors under multiple light stimuli response. This shows the greater application potential of phosphor in the fields of anti‐counterfeiting and information encryption. This study can also provide a new view to study the more high‐performance and multifunctional upconversion phosphor.

Upconversion Luminescence with Bis-pyclen Yb(III) Chelates: Crown vs. Linear Polyether Linkers in Discrete Heteropolynuclear Architectures.

Ligands combining two lateral bis-pyridyl-phosphonated-pyclens were synthesized, using a flexible linear pegylated linker (L2) or a bulkier K22 crown-ether (L3). A functionalized pyridyl-phosphonated-pyclen (L1) was also prepared as a mononuclear analogue. Coordination behavior of lanthanide cations was studied via NMR titration with Lu for L1, and UV/Vis and luminescence spectroscopy with Yb for L2/L3. Strong coordination of two Yb atoms enabled isolation and spectroscopic characterization of dinuclear complexes in H2O and D2O. Excited state lifetime analysis at 980 nm revealed strong protection of Yb cations, with no coordinated water molecule. Upon titration of the isolated dinuclear Yb complexes with Tb cations, cooperative upconversion (UC) sensitization of Tb in the visible was observed upon excitation of Yb at 980 nm in D2O. In the absence of Tb, the Yb complexes also exhibited cooperative luminescence with a weak emission band around 500 nm upon NIR Yb excitation. Efficient UC with Tb was only observed after thermal treatment, suggesting a slow kinetic of formation of the UC species. [Yb2TbL3] showed weak Tb centered UC emission, while the dinuclear complex of L2 displayed more intense UC emission up to two equivalents of Tb, forming [(Yb2L2)Tbx] (x=1-2), with the tetranuclear heterometallic complex being the most intense emitter. Log-Log plot analysis confirmed the two-photon nature of the UC process.

Upconversion Luminescence with Bis‐pyclen Yb(III) Chelates: Crown vs. Linear Polyether Linkers in Discrete Heteropolynuclear Architectures

Ligands combining 2 lateral bis‐pyridyl‐phosphonated‐pyclens were synthesized, using a linear pegylated linker L2 or a K22 crown‐ether L3. A functionalized pyridyl‐phosphonated‐pyclen L1 was also prepared as a mononuclear analogue. Coordination behavior of lanthanide cations was studied via NMR titration with Lu for L1, UV‐Vis and luminescence spectroscopy with Yb for L2/L3. Strong coordination of two Yb atoms enabled isolation and spectroscopic characterization of dinuclear complexes in H2O and D2O. Excited state lifetime at 980nm revealed strong protection of Yb cations, with no coordinated water. Upon titration of the isolated dinuclear Yb complexes with Tb cations cooperative upconversion (UC) sensitization of Tb in the visible was observed (excitation of Yb, 980nm, D2O). In absence of Tb, the Yb complexes also exhibited cooperative luminescence with a weak emission band around 500nm upon NIR Yb excitation. UC with Tb was only observed after thermal treatment, suggesting a slow kinetic of formation of the UC species. [Yb2TbL3] showed weak Tb centered UC emission, while the dinuclear complex of L2 displayed more intense UC emission up to two equivalents of Tb, forming [(Yb2L2)Tbx] (x=1‐2), with the tetranuclear heterometallic complex being the most intense emitter. Log‐Log plot analysis confirmed the 2‐photon nature of the UC process.

Spectral Separation of Up-Conversion Luminescence Processes

Here, we present a novel method for the separation of overlapping emission spectral lines corresponding to nonlinear processes, which differ by effective nonlinearity with respect to the pump field power. The method exploits the factorization of wavelength and pumping power dependencies of the components processes contributions to the total luminescence. The advantage of our method is an ability to be self-testing and robust with respect to noise and experimental imperfections. We successfully demonstrate functionality of the method in the experiment with up-conversion luminescence of the fluorophosphate glass doped with rare-earth ions Yb3+ and Tm3+ pumped by 975 nm CW diode laser.

The upconversion luminescence biomonitoring and biological properties of rare earth oxide-inorganic composite microspheres enhanced by lithium

Multiple myeloma is the second most common hematologic malignant tumor, which can result in complications such as osteolytic fractures and bacterial infections. The side effects of chemotherapy limit the dosage of drugs, which can easily lead to multidrug resistance. Moreover, the dose and distribution of drugs within the body significantly influence the therapeutic efficacy of drugs. Therefore, it is highly necessary to improve multidrug resistance and bacterial infection in the treatment of multiple myeloma, repair bone defects caused by bone pain, and monitor the real-time dynamics of drugs. This work proposes a novel rare earth oxide-inorganic composite (7Li-MBGs:2Er/2Yb-0.75MTO) as a drug delivery platform for the treatment of multiple myeloma. 7Li-MBG, which have bone repair functions, serve as inorganic matrix materials, while Er2O3 and Yb2O3 act as activators and sensitizers, respectively. MTO is used as a therapeutic drug for treating myeloma. The drug release process of MTO was successfully monitored by upconversion luminescence. Cell experiments confirmed that 7Li-MBGs:2Er/2Yb-0.75MTO has a certain long-term therapeutic effect on multiple myeloma, and its mechanism of action is consistent with its drug release kinetics. Moreover, the synergistic effect of rare earth oxides, alkali metal ions and MTO endows 7Li-MBGs:2Er/2Yb-0.75MTO with high antibacterial and osteoinductive abilities, and thus playing a role in enhancing the drug resistance of infectious bacteria, preventing bacterial infection, repairing bone defects and monitoring the real-time dynamics of drug release during multiple myeloma therapy. Therefore, the 7Li-MBGs:2Er/2Yb-0.75MTO multifunctional drug delivery platform synthesized in this work provides a new idea for the treatment of multiple myeloma and biomonitoring.

Fluorescent/Circular Dichroic Dual-Mode Chiral Upconversion Nanocomposite for Diagnosis and Treatment of Rheumatoid Arthritis.

Chiral nanophotonic materials have emerged as ideal candidates for biosensing applications due to their exceptional sensitivity. However, the inability to directly visualize chiral signals limits their broader application, particularly in disease diagnosis and treatment. In this study, we introduce a chiral nanocomposite based on upconversion nanoparticles (UCNPs), denoted UCNPs@L-POM, that exhibits both upconversion luminescence (UCL) and circular dichroism (CD) signals. This dual-signal system enables ultrasensitive detection and in vivo imaging of ·OH. The detection limits for UCL and CD signals in aqueous solution are 6.258 and 0.912 μM, respectively. This dual-mode sensing approach is also effective at the cellular level. As a demonstration, UCNPs@L-POM enables in situ imaging diagnosis of rheumatoid arthritis (RA), characterized by elevated levels of ·OH expression. Additionally, through the oxidation reaction induced by ·OH, UCNPs@L-POM effectively alleviates paw inflammation and promotes the healing of RA. This work offers new prospects for biological applications of chiral nanocomposites.

A CRISPR-Cas12a-mediated dual-mode luminescence and colorimetric nucleic acid biosensing platform based on upconversion nanozyme

In this study, a CRISPR-Cas12a-mediated dual-mode upconversion luminescence/colorimetric nucleic acid biosensing platform is developed based on UCNP@SiO2/CeO2 (UNSC) nanozyme. Here, UNSC is conjugated with single-stranded DNA (ssDNA) probes used as both peroxidase-like nanozyme and upconversion luminescence donors. When no target nucleic acid is present, ssDNA-conjugated UNSC attaches on magnetic graphene oxide (MGO) via pi-pi stacking force, resulting in upconversion luminescence quenching (OFF) and no color change after magnetic removal of nanozymes attached on the MGO. In the presence of target nucleic acid, Cas12a is specifically activated by targeted nucleic acid and indiscriminately cleaves the ssDNA probes on UNSCs. UNSCs then detach from the MGO surface due to the weakening of binding force, leading to upconversion luminescence recovery (ON) and colorimetric change due to the existence of free nanozyme in the 3,3’,5,5’-tetramethyl-benzidine assay. As a proof-of-concept, this biosensing platform shows a limit of detection of around 320 fM in the upconversion luminescence mode and ∼28.4 pM in the colorimetric mode for nucleic acid detection, respectively. This UNSC nanozyme-based CRISPR-Cas12a dual-mode biosensing system also demonstrates high selectivity, good repeatability, and facile operation, which allows easy adaption to other nucleic acid-based detection only by redesigning the sequence of CRISPR RNA.

Near-infrared nonlinear WLEDs with high stability through atomic-level regulation and photosensitive resin encapsulating by 3D printing

Upconversion luminescence (UCL) is a nonlinear opticalphenomenon where long wavelength radiation is converted to shorter wavelength via a two-photon or multi-photon mechanism. The construction of near-infrared nonlinear WLEDs can achieve effective utilization of sunlight. This work starts with "functional Motifs" and regulates the nonlinear luminescent materials at the molecular level by combining DFT calculations and high-throughput techniques. As expected, the optimized geometric structures, band structures, and density of states of Ba2YbF7:Ln3+ were successfully obtained by assembling [BaBr4] and [LnBr4] functional Motifs. Subsequently, Ba2YbF7:Ln3+ single phosphor was prepared and further encapsulated into resin to achieve highly stable upconversion white light using 3D printing technology. After being placed for 8 months, the luminescence intensity and spectral shape of the resin coated sample remain unchanged. The color coordinates of the WLED device constructed with Ba2YbF7:Tm3+/Er3+ single fluorescent powder is (0.3086, 0.3163) and the related color temperature (CCT) is 6863 K. The optimized material has a maximum color rendering index of 83. This work provides new insights and ideas for improving the luminescence stability of upconversion WLED using 3D printing technology.

Activation of Tm3+ single-photon NIR-to-NIR upconversion luminescence through Yb3+ doping in Tm2WO6 phosphor

Ceramic phosphors Tm2-xWO6:xYb3+ synthesized by solid-state reaction method. The up-conversion (UC) dynamics in the Yb3+-doped Tm2WO6 phosphor were investigated, which demonstrated a single-photon UC process from a near-infrared (NIR) excitation at 980 nm to an NIR emission corresponding to the 3H4 → 3H6 transition of Tm3+. X-ray photoelectron spectra confirmed the chemical states of the constituent elements. The diffuse reflectance spectra confirmed that Tm2WO6 requires doping with Yb3+ ions in order to be able to absorb the energy at 980 nm. UC emission properties of the phosphors depend on the Yb3+ ion concentration. NIR emission of Tm3+ is much stronger than visible emissions when Yb3+ doping. The NIR and red emissions were caused by a single-photon UC process, whereas the blue emission was caused by a two-photon process. The temperature-dependent UCL showed an initial rise in the UC intensity and then a consistent decrease with the variation in temperature.

Outstanding pure green upconversion luminescence in LaZrTa3O11:Er3+/Yb3+ phosphors prepared by molten salt synthesis with B2O3 flux

AbstractHexagonal Er3+/Yb3+ co‐doped LaZrTa3O11 (LZTO) phosphor was prepared by molten salt synthesis with B2O3 flux. Holding temperature, holding time, solute and solvent ratio were regulated. The green upconversion luminescence (UCL) integral intensity of the optimal sample can reach 29.2% of β‐NaYF4:Er3+/Yb3+ under 980 nm laser excitation. This outstanding pure green UCL is due to the low phonon energy, Er3+/Yb3+ monolayer (2D) distribution, asymmetry of Er3+/Yb3+ doped lattice sites, and low oxygen vacancy. The maximum relative temperature sensitivity attains 0.01221 K−1 at 303 K by employing luminescence intensity ratio (LIR) technique. LZTO:Er3+/Yb3+ phosphor can be used in temperature sensing.

Fluorescence sensor array for highly sensitive pattern recognition of biothiols in food based on tricolor upconversion luminescence metal-organic frameworks

Fluorescence nanomaterial sensors have exhibited excellent application potential in biothiols analyses. The fluorescence sensor arrays constructed from upconversion luminescence metal-organic frameworks nanocomposites (LMOFs) can provide impressive discrimination and exquisite fingerprinting capabilities for extremely similar analytes. Herein, an upconversion fluorescence sensor array based on LMOFs featuring UiO-type metal-organic frameworks-functionalized lanthanide-doped upconversion nanoparticles was proposed, wherein Cu2+ can make the fluorescence quenching of LMOFs and preferentially bind biothiols to recover fluorescence in different degrees forming unique fingerprinting. The fluorescence sensor array displayed an excellent pattern recognition for five biothiols (glutathione, homocysteine, N-acetylcysteine, and L/D-cysteine) even at 50 µM by linear discriminant analysis, and the discernment for the enantiomers of L/D-cysteine, as well as the accurate identification (90.0% accuracy) of biothiols in food samples (tea beverage and white wine). Such fluorescence sensor array might provide a simple and efficient detection method for biothiols.

UV-induced coumarin-based spiropyran gradient photodimerization and photoisomerization to construct near-infrared responsive gradient hydrogel actuators in one-step

In recent years, the fabrication process of near-infrared (NIR) light-driven gradient hydrogels remains complex. Furthermore, NIR light-driven hydrogels based on the photothermal conversion mechanism have continued to face challenges in achieving spatio-temporal control of the internal structure due to the diffusive nature of heat. Therefore, it is sensible to develop NIR light-driven gradient hydrogels based on the near-infrared upconversion luminescence mechanism through a simple method. In this study, a novel photoresponsive coumarin-based spiropyran monomer (SPCMA) was designed and synthesized, followed by the fabrication of a series of double gradient hydrogels (MHMs) with rapid NIR light-driven capability and reusability through fast in situ photopolymerization of the precursor comprising SPCMA, upconversion nanoparticles (MUCNPs), and hydroxyethyl acrylate (HEA). MHMs exhibit excellent mechanical properties with fracture stress of 4.4 MPa and fracture elongation of 1282 %. Compared with hydrogel using N, N′-Methylenebis(2-propenamide) as a crosslinker, MHMs possess outstanding NIR light-driven capability and reversible cycling characteristics. MHMs rapidly transform from a three-dimensional spiral tubular to a sheet-like morphology within 30 s of NIR light irradiation and achieve a larger actuating angle of 450° within 120 s. Additionally, MHMs maintain similar driveability to the original samples after 10 cycles of NIR light-driven and UV light-recovery processes. More importantly, cargoes with seven times the mass of the "gripper" are firmly grasped and easily lifted by the "gripper" prepared using MHMs within 60 s of NIR light irradiation, demonstrating its powerful gripping ability. This work offers a new strategy for the development of biomimetic smart gradient materials.