Dual-functional Materials Research Articles

Ni promoted Fe-CaO dual functional materials for calcium chemical dual looping

Reverse water–gas shift reaction using renewable H2 is a promising route for CO2 upgrade, however, it is restricted by the equilibrium. The chemical looping reverse water–gas shift reaction using oxygen carriers (i.e. Fe) has proven a more effective CO2 utilization process to produce CO. However, CO2 with high purity is needed to obtain concentrated CO. Herein, we propose a calcium chemical dual looping using one-pot sol–gel synthesized Ca-Fe dual functional materials (DFMs). The CO2 in the exhaust gas (∼10% CO2) can be captured and transformed into carbonates and then in-situ converted into CO through continuous chemical looping in H2 atmosphere. This process avoids CO2 enrichment, storage and transportation and simultaneously realizes efficient CO2 conversion. The Ca-Fe DFMs possessed significantly improved catalytic efficiency (enhanced real-time CO generation rate) compared to CaO. It is found that Ni1Fe9-CaO could optimally achieve 11.3 mmol gDFM−1 CO yield, 82.5% CO2 conversion and 99.9% CO selectivity at 650 °C. Notably, Ni1Fe9-CaO displayed high CO2 conversion (>80%) and CO selectivity (>99.9%) during the cycle tests and possessed enhanced stability in relation to CO yield after 10 cycles (20.9% and 35.5% decrease for Ni1Fe9-CaO and CaO, respectively). Herein, Ca2Fe2O5 plays two roles: acting as an oxygen carrier for in-situ chemical looping to produce CO and a thermally stable physical barrier to retard the sintering of CaO. It is noted that Fe-related species could be reduced into the metallic state at the end of hydrogenation, resulting in CO formation in the following CO2 capture process.

Dual-functional bioactive silk sericin for osteoblast responses and osteomyelitis treatment.

Sericin, a natural protein from silk cocoon, has been reported for various biological properties in the biomaterials field. Modified forms of sericin have been studied for bone tissue engineering, while its unmodified form has been scarcely reported. Therefore, the purpose of this study was to evaluate physical and biological properties of unmodified sericin for potential use in bone surgery. Sericin was extracted from silk cocoons using a chemical-free boiling method. Sericin extract showed distinct bands with molecular weight ranging from 25 to 42 kDa including smear bands. Fourier transform infrared spectra presented characteristic peaks of amide I, II, and III, confirming the chemical composition of sericin. Based on biological activity, sericin extract at a concentration of 40 μg/mL increased the proliferation of osteoblast cells up to 135%, compared with the untreated control. Moreover, increase in antibacterial activity against Staphylococcus aureus, both clinical isolates and the reference strain ATCC 29213, was demonstrated for sericin extract with normal saline, while no antibacterial activity was observed for sericin with broth. It was found that sericin with normal saline showed higher zeta potential than sericin without normal saline, indicating higher system stability. This was confirmed by the average particle size of sericin extract with NaCl (3,249.3±226.1 nm) showing approximately 10 times smaller than sericin solution (29,015.9 ± 8,085.6 nm). Furthermore, sericin extract at the minimal inhibitory concentration significantly reduced the biofilm formation of S. aureus up to 95%. The study indicates biological activities of sericin, which could be applied as a dual-functional bioactive material to support bone regeneration and treat bone infections.

Formulation and processing of dual functional Adsorbent/Catalyst structured monoliths using an additively manufactured contactor for direct Capture/Conversion of CO2 with cogeneration of ethylene

• Formulation and processing of dual functional adsorbent/catalyst monoliths. • Implementation of DFM monoliths into direct air capture/conversion of CO 2 . • Metal screening of 3D-printed DFM monoliths in ODHE in a single bed process. • 65.2% CO 2 conversion and 98% C 2 H 4 selectivity was obtained over V 2 O 5 -CaO/ZSM-5. Utilizing CO 2 as a mild oxidant for oxidative dehydrogenation of ethane (ODHE) is an attractive way of recycling this greenhouse contaminant. Typically, CO 2 capture and conversion processes are performed in separate beds, however, combining these processes into one bed incurs advantages of lower thermal gradient and reduced energy costs. This study formulated the first generation of structured dual-functional materials (DFMs) by directly 3D printing metal-oxide-CaO/ZSM-5 inks into monolithic contactors. Specifically, we 3D-printed monoliths with V, Ga, Ni, or Ti dopants to perform metal screening and determine which metal generates the best structured DFM for combined CO 2 capture and utilization in ODHE. The samples were vigorously characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), N 2 physisorption, NH 3 -temperature programmed desorption (NH 3 -TPD), H 2 -temperature programmed reduction (H 2 -TPR), energy dispersive spectroscopy (EDS), and Pyridine Fourier Transform Infrared Spectroscopy (Py-FTIR). Their CO 2 capture/ODHE performances were assessed with CO 2 adsorption at 600 °C and ODHE of 25 mL/min 7% C 2 H 6 at 700 °C. The combined adsorption/catalysis experiments indicated that the best performance was observed in V-CaO/ZSM-5 which achieved a staggeringly high CO 2 capture (5.4 mmol/g), 65.2% CO 2 conversion, 36.5% C 2 H 6 conversion, 98% C 2 H 4 selectivity, and 35.8% C 2 H 4 yield as well as zero thermal cracking after 40 min-on-stream. This performance exceeded that of any previously reported material for combined CO 2 capture and ODHE utilization, indicating this novel printing method can generate DFMs with exceptional potential for combined CO 2 capture and utilization processes.

Tuning basicity of dual function materials widens operation temperature window for efficient CO2 adsorption and hydrogenation to CH4

Mitigation of CO2 emissions by integrated CO2 capture and utilization (ICCU) is challenging. This work focuses on widening operation temperature window of the hydrogenation of adsorbed CO2 to CH4. For this, a set of dual function materials (DFMs) 4%Ru-x%Na2CO3-y%CaO/γ-Al2O3 are prepared. DFMs are deeply characterized by N2 adsorption-desorption, XRD, H2 chemisorption, TEM, H2-TPR and CO2-TPD. The catalytic behavior, in cycles of CO2 adsorption and hydrogenation to CH4, is evaluated and the temporal evolution of the concentration of reactants and products is analyzed. The presence of both adsorbents in the DFMs improves ruthenium dispersion and the basicity is modulated with the Na2CO3/CaO ratio. Ru-8Na/8Ca improves methane production over the whole temperature window compared to DFMs based only on a unique adsorbent. The best results are assigned to the promotion of contact between the carbonates of medium strength with the metallic sites, which boost the CO2 adsorption and hydrogenation to CH4.

Construction of multifunctional NH2-UiO-66 metal organic framework: sensing and photocatalytic degradation of ketorolac tromethamine and tetracycline in aqueous medium.

Existence of pharmaceutical residues in water has endangered environmental pollution worldwide, which makes it ineludible to develop prospective bifunctional materials which not only possess excellent fluorescence behaviour to monitor pharmaceuticals but also exhibit simultaneous photocatalytic removal efficiency. Strengthened by functionalized metal organic framework (MOF) materials, we present here an amine functionalized zirconium-based MOF NH2-UiO-66 which has been successfully synthesized using solvothermal approach. The as prepared MOF was subjected to numerous structural, morphological and compositional characterizations. Interestingly, featured by the excellent fluorescent intensity of MOF modulated by LMCT effect, NH2-UiO-66 was screened to detect pharmaceutical compounds with KTC and TC in aqueous solution. The prepared functionalized MOF showcased excellent sensing platform with magnificent response range (0‒3µM), lower limit of detection (160nM; KTC and 140nM; TC), excellent selectivity and influential anti-interference capability. More importantly, the practical utility of the proposed sensor was further explored for the determination of pharmaceutical drugs in real water samples with suitable recoveries. Simultaneously, the synthesized MOF also exhibited high photocatalytic efficiency towards the removal of KTC and TC under solar light irradiation. The degradation efficiency for KTC and TC was found to be 68.3% and 71.8% within 60 and 280min of solar light, respectively. Moreover, excellent recyclability was demonstrated by the current synthesized system over five cycles. Overall, this study presents a feasible route for the utilization of functionalized MOFs as potential dual functional materials towards the simultaneous detection and degradation of specific pharmaceuticals from aqueous medium.

Substitution effect on solid parking motif and luminescence of diphenylfuro[2,3-b]quinoxaline isomers

The organic molecules combining light-emitting and charge-transporting property are highly expected. We designed and synthesized a pair of isomers, 2,6-diphenylfuro[2,3-b]quinoxaline (26dPFQ) and 2,7-diphenylfuro[2,3-b]quinoxaline (27dPFQ), and investigated effect of changing substituent position on molecule packing motif, conducting and luminescence feature of resulting materials. In CH2Cl2 solution, both isomers, 26dPFQ and 27dPFQ, emit deep blue light with a wavelength of 422 nm and shows photoluminance quantum yield (PLQY) of 58.9% and 48.7%, respectively. In crystal, the 26dPFQ employs H-type packing motif and retains blue florescent emission with low PLQY (10.0%) while 27dPFQ adopts J-aggregated packing motif and shows enhanced green fluorescent emission with a PLQY of 55.0%. The organic light-emitting devices for both emitters show deep blue emission, the EL peak at 410 nm for 26dPFQ and 424 nm for 27dPFQ, and respectively presents the maximum EQE of 1.2% and 1.0%. The 26dPFQ shows better charge transport capability over 27dPFQ. Our results suggested 2,6-substitution on furo[2,3-b]quinoxaline core are expected to afford such dual functional materials.

Integrated two-phase free radical hydrogel: Safe, ultra-fast tooth whitening and antibacterial activity

The growing demand for brilliant smile and tooth whitening has led to the increasing significance of tooth whitening methods. However, the development of tooth whitening materials with high efficiency and safety has been considered to be an urgent challenge. Here, we report a novel tooth whitening strategy, which overcomes the limitation of conventional methods, shows excellent tooth whitening efficiency and safety, and even exhibits outstanding antibacterial activity. Inspired by stomata and chloroplasts in green leaves, we have developed an integrated two-phase free radical hydrogel (TP-GEL), which integrates solid-phase and liquid-phase free radical functional components fabricated by cold plasma technology. TP-GEL demonstrated safe and ultrafast tooth-whitening effect with or without visible light, which can be more significant than that of 30% H2O2, the commonly whitening material in dental clinical practice. More importantly, we also avoid the damage to enamel, such as microhardness, roughness, surface morphology. Benefiting from free radicals, much higher antibacterial properties than commercial products (Chlorhexidine) was obtained. This research provides fundamental design criteria for the development of dual functional oral health care materials with advanced tooth whitening and antibacterial activity.

Robust under-liquid dual super-lyophobicity cement material for anti-fouling and oily wastewater treatment

Materials of under-liquids (water/oil) dual super-lyophobicity require special micro/nano morphology. However, such material surfaces are mechanically weak and readily worn, which restricts their practical applications. Herein, we report a robust self-similar under-liquid dual super-lyophobicity anti-fouling cement which demonstrates stable underwater super-oleophobicity (θo/w > 150°) and under oil super-hydrophobicity (θw/o > 150°) via a simply mixed cement and water, without other organic reagents and professional preparation technology. The obtained material not only owns good under-liquids mechanical robustness but also has very excellent anti-fouling property. This surface material still has the anti-oil-fouling property once its surface is mechanically damaged, due to its surface self-similar functionality. Importantly, the surface maintained their excellent super-lyophobic functionality due to the similar property after turbulent jets (5 m range), abrasive belt wear, blade cutting (transverse cutting), highly-viscous tape peeling (VHB, 3 M), and ASTM standard adhesion (scratch spacing and cutting spacing). Cement could separate from oil/water mixtures, the separation efficiency for oil was above 97.5% at 30 cycles. Our study provides an eco-friendly, green, simple, low-cost, and easily mass-produced strategy to the fabrication of super-lyophobic materials in oil/water systems dual functional materials, which will benefit applications in diverse fields.

Chemically etched CeO2-x nanorods with abundant surface defects as effective cathode additive for trapping lithium polysulfides in Li-S batteries

The commercialization of Li-S batteries has been seriously hindered by the notorious polysulfides shuttling and sluggish redox kinetics. To effectively address these technical issues, in this work, oxygen-deficient CeO2-x nanorods (NR) decorated on free-standing carbon cloth (CeO2-x NR@CC) were used as a promising dual-functional cathode host material to enhance the electrochemical and cycling performance of Li-S batteries. The oxygen-deficient CeO2-x NR were prepared in a facile processing route by tuning the surface structures of pristine CeO2 NR in strong reducing NaBH4 solution. In contrast to the pristine CeO2NR@CC control sample, chemically etched CeO2-x NR@CC with abundant implanted oxygen vacancies effectively trapped the polysulfides and dramatically accelerated electron charge transfer, leading to faster redox kinetics. The main working mechanism of CeO2-x NR@CC on the improved electrochemical performance was attributed to chemical binding effect on trapping lithium polysulfides and even promoting the conversion of polysulfides, thanks to reversible Ce3+/Ce4+ transformation, oxygen vacancies, and other surface defects. Hence, the CeO2-x NR@CC electrode delivered an outstanding initial capacity of 1358 mAh g−1 at 0.2C for the 1st cycle and a superb sulfur utilization of 81%, compared to an initial capacity of 1176 mAh g−1 at 0.2C and a sulfur utilization of 70% for the CeO2 NR@CC electrode. The improved electrochemical performances of the CeO2-x NR@CC electrode can be mainly attributed to the successful adsorption of more dissolvable polysulfides by the dual-functional cathode host materials that combine the physical confinement of conductive CC and the chemical binding of CeO2-x NR with ample surface defects.

Scintillation and dosimetric properties of LiF/CaF2:Dy eutectic composite

Scintillation and dosimetric properties of a LiF/CaF2:Dy eutectic composite have been studied. In the X-ray induced emission spectrum and decay curve, we observed luminescence due to self-trapped exciton of CaF2 and 4f–4f transitions of Dy3+ ions. The LiF/CaF2:Dy eutectic composite showed the light yield of 3000 photons/neutron as a neutron scintillator. The LiF/CaF2:Dy eutectic composite showed the measurable range from 1 mGy to 10 Gy as a thermoluminescence dosimetric material. The LiF/CaF2:Dy eutectic composite can act as a dual functional material for neutron detection and X-ray dosimetry.

Nanoarchitectonics of uniformly distributed noble-metal-free CoP in g-C3N4 via in-situ fabrication for enhanced photocatalytic and electrocatalytic hydrogen production

Developing an efficient, robust and low-budget bifunctional material for hydrogen evolution is a daunting challenge, which has attracted plenty of researchers’ interest. Herein, we report the non-noble metal bifunctional g-C3N4/CN/CoP catalysts in situ formed for both photocatalytic and electrocatalytic hydrogen production through a convenient phosphorization process. It was found that the optimal g-C3N4(90)/CN300/CoP3 composite not only had the best photocatalytic hydrogen production rate (29.78 mmol·g−1·h−1) in the dye sensitization system, but also had an excellent electrocatalytic hydrogen evolution activity, with an overpotential of 221 mV at 10 mA·cm−2. The XRD, FT-IR, TG, et al. confirm the close contact between ZIF-Co and g-C3N4 in the ideal g-C3N4/ZIF-Co precursor could expediently achieve the uniformly distributed CoP to accelerate electron transfer and reduce the recombination rate of charge. This work can provide a novel strategy to fabricate non-noble metal dual-functional materials for photocatalytic and electrocatalytic hydrogen production to solve energy crises and environmental further.

Process evaluation and kinetic analysis of 3D-printed monoliths comprised of CaO and Cr/H-ZSM-5 in combined CO2 Capture-C2H6 oxidative dehydrogenation to C2H4

In this study, dual-function materials (DFMs) comprised of CaO and Cr/H-ZSM-5 were formulated in 3D-printed monolithic structures and investigated in a combined process for capture and utilization of CO2in oxidative dehydrogenation of C2H6 to C2H4 (CO2-ODHE). Various formulation strategies were employed to fabricate these DFM structures. Two bed designs were considered: i) a layered-bed in which adsorbent (CaO) and catalyst were printed separately and stacked on top of each other, and ii) a single-layer bed where the adsorbent-catalyst materials were 3D-printed into a singular monolith and loaded into the bed as DFMs. Between these, the layered-bed displayed enhanced performance as compared to the composite DFMs, as this configuration generated a 3.73 mmol/g CO2 adsorption capacity, 42.5% C2H6 conversion, 90.6% C2H4 selectivity and 38.6% C2H4 yield compared to 2.4 mmol/g CO2 adsorption capacity, 37.9% C2H6 conversion, 89% C2H4 selectivity and 33.8% C2H4 yield in the best singular monolith configuration. The enhanced performance of this configuration was attributed to a higher degree of adsorptive site accessibility and a lesser degree of active site blockage from intraparticle binding (as evident from the textural properties). This work also assessed the effects of monolith cell density on CO2 adsorption and utilization for ODHE by varying the cells per square inch (cpsi) from 200 to 600 cpsi. These experiments revealed that increasing the cell density from 200 to 600 cpsi enhanced the overall mass transfer coefficient from 0.40 × 10-2 to 1.01 × 10-2 s-1 due to a sizable enhancement in film mass transfer between the two geometric designs. Such enhancement improved the C2H4 selectivity and yield to 92 and 45.1% in the 600 cpsi sample. As such, this work also indicated that higher cell densities lead to better performance of the layered-bed configuration, where the optimum configuration is separate stacking of the adsorbent and catalyst phases. Overall, these findings provide a deeper understanding of DFM materials, bed configuration, and establish a groundwork which can be used to optimize their structures for CO2 adsorption-reaction processes.

MoS2 nanosheets coupled with double-layered hollow carbon spheres towards superior electrochemical activity

MoS2 nanosheets decorated double-layered hollow carbon spheres (DLHCs@MoS2) were synthesized to form a core-shell structure for enhanced electrochemical activity. Double-layer hollow carbon spheres (DLHCs) was first prepared using a template route while the vertical growth of MoS2 nanosheets was carried out via a hydrothermal synthesis. X-ray absorption near edge structure and X-ray absorption fine structure measurement confirmed that MoS2 was strongly coupled with DLHCs through Mo-O-C hetero-interface. As a dual-functional nanocomposite material, DLHCs@MoS2 revealed ideal performance in terms of hydrogen evolution reaction and supercapacitors. DLHCs as matrix materialsplay an important role to decrease the agglomeration of MoS2 nanosheets, expose more active sites,and improve conductivity. Because of the core-shell structure, DLHCs@MoS2 is more conducive to expose active sites compared with pure MoS2 nanosheets. DLHCs@MoS2 exhibited low Tafel slope and small onset potential. In addition, DLHCs@MoS2 composites used as supercapacitor electrode revealed excellent specific capacitance of 399.4 Fg−1 in acurrent density of 0.5 Ag−1. This result provides an idea for synthesizing low-cost and high-efficiency dual-functional materials.

Feasibility of switchable dual function materials as a flexible technology for CO2 capture and utilisation and evidence of passive direct air capture.

The feasibility of a Dual Function Material (DFM) with a versatile catalyst offering switchable chemical synthesis from carbon dioxide (CO2) was demonstrated for the first time, showing evidence of the ability of these DFMs to passively capture CO2 directly from the air as well. These DFMs open up possibilities in flexible chemical production from dilute sources of CO2, through a combination of CO2 adsorption and subsequent chemical transformation (methanation, reverse water gas shift or dry reforming of methane). Combinations of Ni Ru bimetallic catalyst with Na2O, K2O or CaO adsorbent were supported on CeO2-Al2O3 to develop flexible DFMs. The designed multicomponent materials were shown to reversibly adsorb CO2 between the 350 and 650 °C temperature range and were easily regenerated by an inert gas purge stream. The components of the flexible DFMs showed a high degree of interaction with each other, which evidently enhanced their CO2 capture performance ranging from 0.14 to 0.49 mol kg-1. It was shown that captured CO2 could be converted into useful products through either CO2 methanation, reverse water-gas shift (RWGS) or dry reforming of methane (DRM), which provides flexibility in terms of co-reactant (hydrogen vs. methane) and end product (synthetic natural gas, syngas or CO) by adjusting reaction conditions. The best DFM was the one containing CaO, producing 104 μmol of CH4 per kgDFM in CO2 methanation, 58 μmol of CO per kgDFM in RWGS and 338 μmol of CO per kgDFM in DRM.

A new {Cu3–Gd2} cluster as a two-in-one functional material with unique topology acting as a refrigerant and adsorbent for cationic dye

A new Cu–Gd system as a dual functional material (as a magnetic refrigerant as well as a cationic dye adsorbent) is designed and explored.

Facile synthesis of Ni(OH)2 nanoarrays on graphene@carbon fabric as dual-functional electrochemical materials for supercapacitors and capacitive desalination.

A high-performance Ni(OH)2 nanoarray on graphene (RGO)@carbon fabric nanocomposites with hierarchical nanostructures were facilely synthesized, which involves (i) coating of graphene on a carbon fabric; and (ii) in situ growth of Ni(OH)2 nanoarray on the graphene surface. It was found that Ni(OH)2 nanoplates grew evenly on the surface of graphene without stacking. This unique structure of the electrode material favors a higher electrochemical active site, endowing the enhancing capacity performance. The morphology and microstructure of the as-prepared composites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) techniques. Capacitive properties of the as-synthesized electrodes were studied via cyclic voltammetry, charge/discharge, and electrochemical impedance spectroscopy in a three-electrode experimental setup. Taking advantage of the unique structure of Ni(OH)2/RGO@carbon fabric nanocomposites, this material as dual-functional electrodes shows decent performance for both supercapacitors and capacitive desalination (CDI). The specific capacitance was calculated to be 1325 F g−1 at 1 A g−1; moreover, this material shows a high rate capability, whereby the capacitance can be maintained at 612 F g−1 even at 10 A g−1. Besides, its performance as potential CDI electrodes was explored. Such high-performance Ni(OH)2/RGO@carbon fabric hierarchical nanostructures can offer great promise in large-scale energy storage device applications.

Effect of the Methanation Kinetics of Ru-Based Dual Functional Materials with Different Base Metals on the Cyclic Performance in Co2 Capture-Methanation

Effect of the Methanation Kinetics of Ru-Based Dual Functional Materials with Different Base Metals on the Cyclic Performance in Co2 Capture-Methanation

An electrochemical sensor–adsorbent for lead (Pb2+) ions in an aqueous environment based on Katiragum–Arginine Schiff base

A dual functional material fulfilling twin objectives; simultaneous sensing and adsorption of Pb2+ ions in an aqueous medium.

Ni Promoted Fe-Cao Dual Functional Materials for Calcium Chemical Dual Looping

Ni Promoted Fe-Cao Dual Functional Materials for Calcium Chemical Dual Looping

Insights into the Effect of Trans-to-Cis Photoisomerization of a Co-coordinated Stilbene Derivative on the Luminescence of Di-β-diketonate Lanthanide Complexes.

Five lanthanide complexes constructed from a stilbene derivative, (E)-N′,N′-bis(pyridin-2-ylmethyl)-4-styrylbenzoyl hydrazide (HL), and two β-diketonates (2-thenoyltrifluoroacetonate, tta), with or without a trifluoroacetate anion (CF3CO2–), namely, [Ln(tta)2(HL) (CF3CO2)] [LnC45H32F9N4O7S2, Ln = La (1), Nd (2), Eu (3), or Gd (4)] and [Yb(tta)2(L)] (YbC43H31F6N4O5S2 (5), L = deprotonated HL), were synthesized and characterized. Crystals of these five complexes were obtained and analyzed by single-crystal X-ray diffraction. These complexes all belonged to the monoclinic P21/c space group. For La3+, Nd3+, Eu3+, and Gd3+, the central lanthanide ion was nine-coordinate with a monocapped twisted square antiprism polyhedron geometry. The central Yb3+ ion of complex 5 was eight-coordinate with a distorted double-capped triangular prism polyhedron geometry. Among the five complexes, trans-to-cis photoisomerization of the stilbene group in gadolinium complex 4 showed the largest quantum yield. Complexes 2, 3, and 4 showed dual luminescence and photoisomerization functions. The luminescence change of complex 3 was reversible upon the trans-to-cis photoisomerization process. The sensitization efficiencies of luminescent europium complex 3 in acetonitrile solutions and in the solid state were 49.9 and 42.6%, respectively. These medium sensitization efficiencies led to the observation of simultaneous photoisomerization and luminescence, which further confirmed our previous report that photoisomerization of the stilbene group within complexes was related to the lanthanide ion energy level and whether a ligand-to-metal center or ligand-to-ligand charge-transfer process was present. In complexes 1–5, in addition to the intramolecular absorption transition of the ligand itself (IL, πHL–πHL* and πtta–πtta*), the presence of a ligand-to-ligand charge-transfer transition between tta and HL (LLCT, πtta–πHL* or πHL–πtta*) indicated whether the triplet-state energy of HL was able to transfer to the excited energy level of the lanthanide ions, leading to different extents of HL photoisomerization. These results provide an important route for the design of new dual-function lanthanide-based optical switching materials.