Molecular Engineering of Near-Infrared-II Photosensitizers with Steric-Hindrance Effect for Image-Guided Cancer Photodynamic Therapy

The design of photosensitizers (PSs) with fluorescence in the second near-infrared (NIR-II, 1000–1700 nm) window remains a challenge, as the introduction of donor or acceptor units with excessively strong electron-withdrawing or donating ability leads to longer-wavelength emission but insufficient production of singlet oxygen (¹O₂). In this study, a series of acceptor-donor-acceptor-donor-acceptor-type PSs are designed by adjusting the steric hindrance of the molecules. Compound BNET forms a dihedral angle of 88° with a nearly vertically twisted backbone to show that the intensity of local emission in the first near-infrared (750–900 nm) region declines in the aggregated state, while the emission peaks of twisted intramolecular charge transfer span over 1000 nm with significant enhancement. The albumin-bound NIR-II PS nanoparticles exhibit efficient ¹O₂ generation, good photostability and biocompatibility, and negligible dark toxicity. The nanoparticles demonstrate high specific NIR-II fluorescence imaging of tumor lesions as well as effective image-guided photodynamic therapy in mice bearing orthotopic colon cancer or pancreatic cancer. The designed NIR-II PS nanoparticles show great potential for biomedical applications.     

Grain-Boundary-Rich Triphasic Artificial Hybrid Interphase Toward Practical Magnesium Metal Anodes

Magnesium metal anodes have attracted widespread attention for their high volumetric capacity and natural abundance, but are precluded from practical applications by poor rate capability and limited lifespan due to sluggish ion-transfer kinetics and uneven deposition behavior. Herein, for the first time a grain-boundary-rich triphasic artificial hybrid interphase, consisting of Sb metal, Mg₃Sb₂ alloy, and MgCl₂, is designed on Mg anode surface by a facile solution treatment method, enabling high-rate and long-cycle Mg plating/stripping behavior. The triphasic artificial hybrid interphase affords high magnesiophilicity and ionic conductivity to reduce the energy barriers for Mg²⁺ desolvation and deposition. Meanwhile, the abundant grain boundaries redistribute Mg²⁺ flux at the electrode-electrolyte interface and guide uniform Mg deposition. Accordingly, the as-designed Mg metal anode achieves ultralong cycling life of 350 h at a high current density of 5 mA cm⁻² and a large areal capacity of 5 mAh cm⁻², outperforming previously reported Mg metal anodes with artificial interphases. Full cells with Mo₆ cathode also show extraordinary stability over a long lifespan of 8000 cycles at a high rate of 5 C. The rational artificial interphase design and the understanding of composition-structure-function relationships shed deep insights into the development of fast-charging and long-cycling Mg metal batteries.     

Eco-Friendly and Highly Efficient Light-Emission Ferroelectric Scintillators by Precise Molecular Design

Hybrid manganese halide has attracted much attention in the field of environment friendly ferroelectric and photo-responsive multifunctional materials. Here, the highly efficient photoluminescent inorganic framework MnBr₄²⁻ is utilized to conceive and synthesize a series of hybrid manganese bromide compounds [RQ]₂MnBr₄ by introducing precisely designed quasi-spherical cations [RQ]⁺ (R  =  H, Me, Et, FEt, Q  =  quinuclidine). The accurate and effective modification of cations not only achieves the satisfactory ferroelectricity, but also enhances the photoluminescence quantum yield from 38.7% to 83.65%. Moreover, [FEtQ]₂MnBr₄ shows a highly efficient X-ray scintillator performance, including a large range of linear response to X-ray dose rate from 0.3 to 414.2  μ Gy_air s⁻¹, a high light yield of 34 438 photons per MeV, and a low detection limit of 258 nGy_air s⁻¹. This work provides an efficient strategy for the preparation of hybrid manganese halide ferroelectrics with highly efficient light-emission and X-ray detection.     

Fluorinated Organic A-Cation Enabling High-Performance Hysteresis-Free 2D/3D Hybrid Tin Perovskite Transistors

2D tin-based perovskites have gained considerable attention for use in diverse optoelectronic applications, such as solar cells, lasers, and thin-film transistors (TFTs), owing to their good stability and optoelectronic properties. However, their intrinsic charge-transport properties are limited, and the insulating bulky organic ligands hinder the achievement of high-mobility electronics. Blending 3D counterparts into 2D perovskites to form 2D/3D hybrid structures is a synergistic approach that combine the high mobility and stability of 3D and 2D perovskites, respectively. In this study, reliable p-channel 2D/3D tin-based hybrid perovskite TFTs comprising 3D formamidinium tin iodide (FASnI₃) and 2D fluorinated 4-fluoro-phenethylammonium tin iodide ((4-FPEA)₂SnI₄) are reported. The optimized FPEA-incorporated TFTs show a high hole mobility of 12 cm² V⁻¹ s⁻¹, an on/off current ratio of over 10⁸, and a subthreshold swing of 0.09 V dec⁻¹ with negligible hysteresis. This excellent p-type characteristic is compatible with n-type metal-oxide TFT for constructing complementary electronics. Two procedures of antisolvent engineering and device patterning are further proposed to address the key concern of low-performance reproducibility of perovskite TFTs. This study provides an alternative A-cation engineering method for achieving high-performance and reliable tin-halide perovskite electronics.     

High-Performance Aqueous Zn2+/Al3+ Electrochromic Batteries based on Niobium Tungsten Oxides

Electrochromic energy storage devices (EESDs) are incorporating electrochromic and energy storage functions, which can visually display energy storage levels in real-time to promote the next generation of transparent battery development. However, their performances are still limited for practical applications. Herein, a self-powered EESD based on complex niobium tungsten oxide is designed using aqueous Zn²⁺ and hybrid Zn²⁺/Mⁿ⁺ (Mⁿ⁺ = Al³⁺, Mg²⁺, and K⁺) electrolytes. The results reveal that the use of Zn²⁺/Al³⁺ hybrid electrolyte achieves superior electrochromic performances including a short self-coloring time, high optical contrast, and excellent cyclic stability. Furthermore, it is also found that the self-coloring process is accompanied by a high discharged capacity of niobium tungsten oxide, with high optical modulation in the Zn²⁺/Al³⁺ hybrid electrolyte. The detailed mechanism on the performances of EESD using various electrolytes is systematically studied. This work provides a simple and effective strategy for an aqueous and self-powered EESD with high optical contrast and good cycle stability.     

Highly-Stable CsPbI3 Perovskite Solar Cells with an Efficiency of 21.11% via Fluorinated 4-Amino-Benzoate Cesium Bifacial Passivation

The poor interface quality between cesium lead triiodide (CsPbI₃) perovskite and the electron transport layer limits the stability and efficiency of CsPbI₃ perovskite solar cells (PSCs). Herein, a 4-amino-2,3,5,6-tetrafluorobenzoate cesium (ATFC) is designed as a bifacial defect passivator to tailor the perovskite/TiO₂ interface. The comprehensive experiments demonstrate that ATFC can not only optimize the conductivity, electron mobility, and energy band structure of the TiO₂ layer by passivation of the undercoordinated Ti⁴⁺, oxygen vacancy (V_O), and free  OH defects but also promote the yield of high-quality CsPbI₃ film by synergistic passivation of undercoordinated Pb²⁺ defects with the  CO group and F atom, and limiting I⁻ migration via F···I interaction. Benefiting from the above interactions, the ATFC-modified CsPbI₃ device yields a champion power conversion efficiency (PCE) of 21.11% and an excellent open-circuit voltage (V_OC) of 1.24 V. Meanwhile, the optimized CsPbI₃ PSC maintains 92.74% of its initial efficiency after aging 800 h in air atmosphere, and has almost no efficiency attenuation after tracking at maximum power point for 350 h.     

In Situ Photosynthesis of an MAPbI3/CoP Hybrid Heterojunction for Efficient Photocatalytic Hydrogen Evolution

Halide perovskite like methylammonium lead iodide perovskite (MAPbI₃) with its prominent optoelectronic properties has triggered substantial concerns in photocatalytic H₂ evolution. In this work, to attain preferable photocatalytic performance, a MAPbI₃/cobalt phosphide (CoP) hybrid heterojunction is constructed by a facile in situ photosynthesis approach. Systematic investigations reveal that the CoP nanoparticle can work as co‐catalyst to not only extract photogenerated electrons effectively from MAPbI₃ to improve the photoinduced charge separation, but also facilitate the interfacial catalytic reaction. As a result, the as‐achieved MAPbI₃/CoP hybrid displays a superior H₂ evolution rate of 785.9 µmol h^?1 g^?1 in hydroiodic acid solution within 3 h, which is ≈8.0 times higher than that of pristine MAPbI₃. Furthermore, the H₂ evolution rate of MAPbI₃/CoP hybrid can reach 2087.5 µmol h^?1 g^?1 when the photocatalytic reaction time reaches 27 h. This study employs a facile in situ photosynthesis strategy to deposit the metal phosphide co‐catalyst on halide perovskite nanocrystals to conduct photocatalytic H₂ evolution reaction, which may stimulate the intensive investigation of perovskite/co‐catalyst hybrid systems for future photocatalytic applications.     

Elucidating the Impact of Mg Substitution on the Properties of NASICON-Na3+yV2−yMgy(PO4)3 Cathodes

Vanadium multiredox-based NASICON-Na_zV_2−yM_y(PO₄)₃ (3 ≤ z ≤ 4; M = Al³⁺, Cr³⁺, and Mn²⁺) cathodes are particularly attractive for Na-ion battery applications due to their high Na insertion voltage (>3.5 V vs Na⁺/Na⁰), reversible storage capacity (≈150 mA h g⁻¹), and rate performance. However, their practical application is hindered by rapid capacity fade due to bulk structural rearrangements at high potentials involving complex redox and local structural changes. To decouple these factors, a series of Mg²⁺-substituted Na_3+yV_2−yMg_y(PO₄)₃ (0 ≤ y ≤ 1) cathodes is studied for which the only redox-active species is vanadium. While X-ray diffraction (XRD) confirms the formation of solid solutions between the y = 0 and 1 end members, X-ray absorption spectroscopy and solid-state nuclear magnetic resonance reveal a complex evolution of the local structure upon progressive Mg²⁺ substitution for V³⁺. Concurrently, the intercalation voltage rises from 3.35 to 3.45 V, due to increasingly more ionic V O bonds, and the sodium (de)intercalation mechanism transitions from a two-phase for y ≤ 0.5 to a solid solution process for y ≥ 0.5, as confirmed by in operando XRD, while Na-ion diffusion kinetics follow a nonlinear trend across the compositional series.     

Low Volume-Expansion,Insertion-Type Layered Silicate Hierarchical Structure For Superior Storage Of Li,Na, K

A hierarchical structure is successfully synthesized by coating polypyrrole (PPy) on the surface of carbon/saponite superlattice (denoted as PPy@C/SAP), and applied as low volume-expansion insertion-type anode for Li, Na, K storage.The synergistic effect of metal Ni, Fe doping, carbon/silicate superlattice, abundant oxygen vacancies and PPy coating leads to a good electronic conductivity and large current discharging capability. As a Si-based material, PPy@C/SAP has excellent storage capability for Li (659 mAh g⁻¹ after 1000 cycles at 2 A g⁻¹ and 550 mAh g⁻¹ after 1000 cycles at 5 A g⁻¹), Na (maximum specific capacity of 533 and 327 mAh g⁻¹ after 50 cycles) as well as K (236 mAh g⁻¹ after 100 cycles). XPS, XANES, XRD, FTIR, HRTEM, SEM are used to detect the hybrid mechanism (bulk insertion and surface conversion) with a volume expansion as low as 9%. Insertion reaction driven by valence state change of Ni, Fe, Si (Ni⁰⇔Ni²⁺, Fe0⇔Fe³⁺, Si²⁺⇔Si⁴⁺) in laminates and conversion reactions between LiOH/Li₂CO₃ and LiH/Li₂C₂ catalyzed by Ni° contribute to the high performance. In the whole electrochemical process, layered structure is retained while the conversion reactions of LiOH (prodeced by laminates dehydroxylation) and Li₂CO₃ (electrolyte decomposition) cause the dynamic evolution of solid ectrolyte interphase. This study develops a promising Si-based anode material for lithium ion batteries, sodium ion batteries and potassium ion batteries, which is significant for designing long cycle life rechargeable batteries.     

Regulating the Water Molecular in the Solvation Structure for Stable Zinc Metal Batteries

Rechargeable aqueous zinc batteries are promising energy storage devices because of their low cost, high safety, and high energy density. However, their performance is plagued by the unsatisfied cyclability due to the dendrite growth and hydrogen evolution reaction (HER) at the Zn anode. Herein, it is demonstrated that the concentrated hybrid aqueous/non-aqueous ZnCl₂ electrolytes constitute a peculiar chemical environment for not only the Zn-ions but also water molecules. The high concentration of chloride ions substitutes the H₂O molecular in the solvation structure of Zn²⁺, while the acetonitrile further interacts with H₂O to decrease its activity. The hybrid electrolytes both inhibit the dendrite formation and HER, enabling an ultrahigh average Coulombic efficiency of 99.9% in the Zn||Cu half-cell and a highly reversible Zn plating/stripping with a low overpotential of 21 mV. Using this hybrid electrolyte, the Zn||polytriphenylamine (PTPAn) full cell deliveres a high discharge capacity of 110 mAh g⁻¹, a high power density of 9200 W kg⁻¹ at 100 °C and maintains 85% of the capacity for over 6000 cycles at 10 °C. This study provides a deep understanding between the solvation structure and columbic efficiency of Zn anode, thus inspiring the development for stable Zn batteries.     

Improvement of 1.53 μm emission and energy transfer of Yb3+/Er3+ co-doped tellurite glass and fiber

To improve the 1.53 μm band emission of Er³⁺, the trivalent Yb³⁺ ions were introduced into the Er³⁺ single-doped tellurite glass with composition of TeO₂–ZnO–La₂O₃, a potential gain medium for Er³⁺-doped fiber amplifier (EDFA). The improved effects were investigated from the measured 1.53 μm band and visible band spontaneous emission spectra together with the calculated 1.53 μm band stimulated emission (signal gain) spectra under the excitation of 975 nm laser diode (LD). It was found that Yb³⁺/Er³⁺ co-doping scheme can remarkably improve the visible band up-conversion and the 1.53 μm band fluorescence emission intensity, and meanwhile improves the 1.53 μm band signal gain to some extent, which were attributed to the result of the effective energy transfer of Yb³⁺:²F_5/2 + Er³⁺:⁴I_15/2 → Yb³⁺:²F_7/2 + Er³⁺:⁴I_11/2. The quantitative study of energy transfer mechanism was performed and microscopic energy transfer parameters between the doped rare-earth ions were determined. In addition, the spectroscopic properties of Er³⁺ were also investigated from the measured absorption spectrum according to the Judd–Ofelt theory, and the structure behavior and thermal stability of the prepared tellurite glass were analyzed based on the X-ray diffraction (XRD) and differential scanning calorimeter (DSC) measurements, respectively.     

X-ray Sensitive hybrid organic photodetectors with embedded CsPbBr3 perovskite quantum dots

X-ray detection is an important technology for medical diagnosis as well as industrial and security inspections. While today's commercial X-ray detectors are bulky, photodetectors based on organic semiconductors have attracted increasing attention owing to their low temperature processing capabilities, flexibility and low cost. Nonetheless, the low X-ray attenuation coefficient of organic semiconductors still hinders their practical application. Herein, a new organic-inorganic hybrid strategy is proposed to improve the X-ray sensitivity of organic photodetectors (OPDs). A solution-processed X-ray sensitive hybrid OPD is fabricated by embedding CsPbBr₃ quantum dots (QDs) into a P3HT:PC₆₁BM bulk heterojunction photodiode. The QDs, acting as embedded scintillators in the organic active layer, maintain a high radioluminescence. The proposed hybrid structure enables indirect X-ray detection in a comprehensive manner. These hybrid photodetectors exhibit suppressed dark current densities in the range of tens of picoamperes per square centimeters for different weight ratios of blended QDs. The best OPD achieves a sensitivity of 229.6 e nGy⁻¹ mm⁻² (3.67 μC Gy⁻¹ cm⁻²) and a dark current of 23.3 pA cm⁻² at a low operating voltage (−3 V) for 20–80 kV “soft” X-rays, thus representing great potential for the development of next generation low cost, portable, and highly sensitive X-ray detectors.     

Preparation and luminescence of europium-doped lanthanum fluoride–benzoic acid hybrid nanostructures

Europium-doped lanthanum fluoride (LaF₃:Eu³⁺) nanoparticles were synthesized using a solvothermal method, and they were then capped with benzoic acid (BA) ligands to form LaF₃:Eu³⁺–BA hybrid nanostructures. The LaF₃:Eu³⁺–BA hybrid nanostructures showed strong luminescence as a result of energy transfer from BA to the Eu³⁺ ions of the LaF₃:Eu³⁺ nanoparticles. The dominant excitation band for the LaF₃:Eu³⁺–BA hybrid nanostructures ranged from 200 nm to 300 nm. It has been shown that the luminescence of LaF₃:Eu³⁺–BA hybrid nanostructures strongly depends on the pH value and content of benzoic acid used in the preparation of the hybrid nanostructures. An X-ray diffraction technique, transmission electron microscopy, luminescence spectroscopy, Fourier transform infrared spectroscopy and a UV–vis spectrophotometer were used to characterize the products.     

Stacked Lamellar Matrix Enabling Regulated Deposition and Superior Thermo-Kinetics for Advanced Aqueous Zn-Ion System under Practical Conditions

Zinc anodes have attracted widespread attention for their intrinsic safety, low cost, and abundant resources, but still suffer from severe irreversibility due to spontaneous corrosion and nonplanar dendrite formation in aqueous electrolytes. In this work, a 3D stacked lamellar matrix (SLM) composed of ZnF₂/Zn₃(PO₄)₂/CF_X is elaborately designed on a Zn substrate via simple chemical/electrochemical reactions, delivering enhanced thermodynamic stability and rapid zinc ions transport kinetics. The abundant ion conduction channels in SLM could also redistribute Zn²⁺ ions flux and further suppress the dendrite growth. With these synergetic effects, the SLM-Zn anodes enable exceptional performance, including a high depth of discharge (90%) in a Zn|Zn symmetrical cell for 187 h, steady charge/discharge process (94.1% retention of SLM-Zn|MnO₂ full cell for 1000 cycles at a harsh rate of 15 C), and low negative/positive capacity ratio (≈3.3) in SLM-Zn|AC hybrid supercapacitor with limited Zn anode (10 µm) and high-load cathode (≈1.77 mA h cm⁻²), which greatly promotes the application of aqueous Zn-ion energy system under practical conditions.     

The Synergistic Activation of Ce-Doping and CoP/Ni3P Hybrid Interaction for Efficient Water Splitting at Large-Current-Density

The high intermediate (H*, OH*) energy barriers and slow mass/charge transfer increase the overpotential of alkaline water electrolysis at large-current-density. Engineering the electronic structure with the morphology of the catalyst to reduce energy barriers and improve mass/charge transportation is effective but remains challenging. Herein, a Ce-doped CoP nanosheet is hybrid with Ni₃P@NF (Ni foam) support to enhance mass/charge transfer, tune energy barriers, and improve water-splitting kinetics through a synergistic activation. The engineered Ce_0.2-CoP/Ni₃P@NF cathode exhibits an ultralow overpotential (η₅₀₀, η₁₀₀₀) of −185, and −225 mV at −500 and −1000 mA cm⁻² in 1.0 m  KOH, along with an excellent pH-universality. Impressively, an electrolyzer using the Ce_0.2-CoP/Ni₃P@NF cathode can afford 500 mA cm⁻² at a cell voltage of only 1.775 V and maintain stable electrolysis for 200 h in 25 wt% KOH (50 °C). Characterization and density functional theory calculation further reveal the Ce-doping and CoP/Ni₃P hybrid interaction synergistically downshift d-band centers (ε_d = −2.0 eV) of Ce_0.2-CoP/Ni₃P to the Fermi level, thereby activate local electronic structure for accelerating H₂O dissociation and optimizing Gibbs free energy of hydrogen adsorption (∆G_H*).     

Suppression of Ionic and Electronic Conductivity by Multilayer Heterojunctions Passivation Toward Sensitive and Stable Perovskite X-Ray Detectors

Organic-inorganic hybrid perovskites are promising candidates for direct X-ray detection and imaging. The relatively high dark current in perovskite single crystals (SCs) is a major limiting factor hindering the pursuit of performance and stability enhancement. In this study, the contribution of dark current is disentangled from electronic (σ_e) and ionic conductivity (σ_i) and shows that the high σ_i dominates the dark current of MAPbBr₃ SCs. A multilayer heterojunctions passivation strategy is developed that suppresses not only the σ_i by two orders of magnitude but also σ_e by a factor of 1.6. The multilayer heterojunctions passivate the halide vacancy defects and increase the electron and hole injection barrier by inducing surface p-type doping of MAPbBr₃. This enables the MAPbBr₃ SC X-ray detectors to obtain a high sensitivity of 19 370 µC Gy_air⁻¹ cm⁻² under a high electric field of 100 V cm⁻¹, a record high sensitivity for bromine self-powered devices, and a low detection limit of 42.3 nGy_air s⁻¹. The unencapsulated detectors demonstrate a stable baseline after storage for 210 days and outstanding operational stability upon irradiation with an accumulated dose of up to 1944 mGy_air.     

Enhanced luminescence of CaSb2O6:Bi3+ blue phosphors by efficient charge compensation

This paper reported an enhanced photoluminescence of CaSb₂O₆:Bi³⁺ by efficient charge compensation. Charge compensated CaSb₂O₆:Bi³⁺,M⁺ (M=Li, Na and K) phosphors were prepared using a co-precipitation technique followed by heat-treatment. The structure and morphology of the as-prepared CaSb₂O₆:Bi³⁺,M⁺ samples were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results revealed that the obtained CaSb₂O₆:Bi³⁺,M⁺ samples are hexagonal crystal structure and this structure was retained regardless of co-doping by Li⁺, Na⁺ or K⁺. All samples showed sphere-like shape with particle size of 40–80 nm. The optical properties of products were studied by UV–vis diffuse reflectivity, photoluminescence spectra and luminescence decay measurements. Under the excitation of 336 nm light, all of the samples exhibited a strong blue emission peaking around 437 nm, which is attributed to the ³P₁–¹S₀ transition of the Bi³⁺ ion. It was found that the charge compensation has significant effect on the photoluminescence properties of CaSb₂O₆:Bi³⁺ and the best luminescence properties have been achieved for CaSb₂O₆:0.75Bi³⁺,0.75 Na⁺. The mechanism for the enhancement of the blue emission has also been studied in detail. Our results suggested that the optical properties of oxide nanostructures can be tailored through co-doping with aliovalent ions and the favorable luminescence properties of CaSb₂O₆:Bi³⁺,Na⁺ make it potential for lighting and display applications.     

Centimeter-Sized Single Crystals of Two-Dimensional Hybrid Iodide Double Perovskite (4,4-Difluoropiperidinium)4AgBiI8 for High-Temperature Ferroelectricity and Efficient X-Ray Detection

Ferroelectricity and X-ray detection property have been recently implemented for the first time in hybrid bromide double perovskites. It sheds a light on achieving photosensitive and ferroelectric multifunctional materials based on 2D lead-free hybrid halide double perovskites. However, the low T_c, small P_s, and relatively low X-ray sensitivity in the reported bromide double perovskites hinder practical applications. Herein, the authors demonstrate a novel 2D lead-free iodide double perovskite (4,4-difluoropiperidinium)₄AgBiI₈ (1) for high-performance X-ray sensitive ferroelectric devices. Centimeter-sized single crystal of 1 is obtained and exhibits an excellent ferroelectricity including a high T_c up to 422 K and a large P_s of 10.5 μC cm⁻². Moreover, due to a large X-ray attenuation and efficient charge carrier mobility (μ)–charge carrier lifetime (τ) product, the crystal 1 also exhibits promising X-ray response with a high sensitivity up to 188 μC·Gy_air⁻¹ cm⁻² and a detection limit below 3.13 μGy_air·s⁻¹. Therefore, this finding is a step further toward practical applications of lead-free halide perovskite in high-performance photoelectronic devices. It will afford a promising platform for exploring novel photosensitive ferroelectric multifunctional materials based on lead-free double perovskites.     

Plasmonic Dual‐Enhancement and Precise Color Tuning of Gold Nanorod@SiO2 Coupled Core–Shell–Shell Upconversion Nanocrystals

The last decade has witnessed the remarkable research progress of lanthanide‐doped upconversion nanocrystals (UCNCs) at the forefront of promising applications. However, the future development and application of UCNCs are constrained greatly by their underlying shortcomings such as significant nonradiative processes, low quantum efficiency, and single emission colors. Here a hybrid plasmonic upconversion nanostructure consisting of a GNR@SiO₂ coupled with NaGdF₄:Yb³⁺,Nd³⁺@NaGdF₄:Yb³⁺,Er³⁺@NaGdF₄ core–shell–shell UCNCs is rationally designed and fabricated, which exhibits strongly enhanced UC fluorescence (up to 20 folds) and flexibly tunable UC colors. The experimental findings show that controlling the SiO₂ spacer thickness enables readily manipulating the intensity ratio of the Er³⁺ red, green, and blue emissions, thereby allowing us to achieve the emission color tuning from pale yellow to green upon excitation at 808 nm. Electrodynamic simulations reveal that the tunable UC colors are due to the interplay of plasmon‐mediated simultaneous excitation and emission enhancements in the Er³⁺ green emission yet only excitation enhancement in the blue and red emissions. The results not only provide an upfront experimental design for constructing hybrid plasmonic UC nanostructures with high efficiency and color tunability, but also deepen the understanding of the interaction mechanism between the Er³⁺ emissions and plasmon resonances in such complex hybrid nanostructure.     

Rare earth doped TiO2-CdS and TiO2-CdS composites with improvement of photocatalytic hydrogen evolution under visible light irradiation

In this paper, we report the obtention of a series of rare earth doped composite Pt/RE/TiO₂-CdS (RE=La³⁺, Eu³⁺, Er³⁺, Gd³⁺) and TiO₂-CdS photocatalysts prepared by a simple mechanical mixed method. The photocatalysts properties were studied by means of ultraviolet-visible spectroscopy, photoluminiscence spectra, X-ray diffraction, transmission electron microscopy, specific surface areas and the electrochemistry method. Photocatalytic hydrogen evolution using Na₂S/Na₂SO₃ as electron donor was investigated under visible-light (λ≥420 nm) irradiation. The rare earth doping enhances the activities of Pt/RE/TiO₂-CdS samples (with 1.0 wt% deposited Pt). Under optimum conditions, the activities of La³⁺, Eu³⁺, Er³⁺, Gd³⁺ doped composite Pt/RE/TiO₂-CdS increase by 62.0%, 40.4%, 34.7% and 30.0% respectively, when compared to that of Pt/TiO₂-CdS, due to the prevention of electron–hole recombination and the flat-band potential of the conduction of TiO₂ shifting negatively by the doping.