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We report the fabrication of PdSm bimetallic nanocrystals with controlled shapes and explore their applications as the electrocatalysts for electroxidation of ethanol (EOR) in alkaline medium. The success of current synthesis relies on the co-reduction of Pd(acac) 2 and Sm(acac) 3 in the presence of N-oleyl-1,3-propanediamine (OPDA) and Mo(CO) 6 at an elevated temperature. For the first time, ultrathin nanostructures composed of Pd-rare earth metal bimetals could be prepared in high purity, in the form of ultrathin porous nanosheets and concave tetrahedra, together with the size/edge length limited to sub-3 nm size range. When serving as electrocatalysts for EOR, the carbon-supported PdSm nanocrystals exhibited in seven-fold increase in mass activity as compared to that of Pt/C, as well as improved reaction kinetics and long-term durability. DFT calculations verify that the PdSm NCs/C catalyst modulate the reaction pathway of ethanol oxidation with lower energy barriers as compared with Pd catalyst, accounting for the improved catalytic performance. The present study provides a feasible strategy to create rare earth metal-doped bimetallic nanocrystals with controlled morphology for rational design over fuel cell catalysts and could be extended to other noble metals or alloys. Ultrathin Sm-doped Pd nanocrystals with two exotic shapes, ultrathin porous nanosheet and concave tetrahedron, are successfully prepared via a one-pot synthesis, exhibiting noticeable enhancement in electrocatalytic activity for ethanol oxidation reaction in alkaline medium. [Display omitted] • Sm-doped Pd nanocrystals were facilely synthesized with ultrathin sizes. • The morphologies of porous nanosheet and concave tetrahedron were obtained. • PdSm NCs/C exhibited enhanced EOR mass activity, reaction kinetics and stability. • DFT calculations suggest the Sm-doping can lower the energy barriers for EOR. [ABSTRACT FROM AUTHOR]

An intense reddish-orange phosphor, Eu 2 SiS 4 :Er 3+ , was developed. The photoluminescence excitation and emission spectra, the lifetime, and the concentration effect are investigated. The results show that an efficient energy transfer occurs from Eu 2+ to Er 3+ , and its efficiency is about 81.0%. The phosphors exhibit an efficient broad absorption band and give reddish-orange emitting light with higher color purity. These results demonstrate that Er 3+ ion with low 4f - 4f absorption efficiency can play a role of activator in narrow reddish-orange emitting phosphor, potentially useful in n-UV/blue GaN-based LED through efficient energy feeding by a strong excitation band of Eu 2+ . [ABSTRACT FROM AUTHOR]

We report the fabrication of "Pt-on-PdAg" heterogeneous nanocrystals in the form of trigonal/hexagonal plate (THNPs) and explored their applications in electroxidation of methanol (MOR) in alkaline medium. In particular, PdAg polyhedral nanoparticles are prepared in advance, followed by the addition of Pt salts to allow in situ galvanic replacement reaction (GRR) between them, leading to the formation of Pt nano-islands on PdAg particle surface and the transformation of the overall morphology into trigon/hexagon. The deliberately designed Pt-"PdAg alloy" interface arising from the hybrid structure greatly enriches the absorption sites, showing noticeable structural advantages in MOR electrocatalysis. Particularly, the carbon-supported Pt-on-PdAg THNPs exhibit nearly 30-fold increase in specific activity as compared to that of commercial Pt/C, as well as enhanced reaction kinetics and long-term durability. DFT calculations suggest that the reaction of CH 3 OH oxidation mediated by PtAgPd is energetically more favorable compared to the similar reaction promoted by Pt, which rationalizes the experimental observation that PtAgPd shows the improved catalytic performance. The present study offers a feasible route to construct trimetallic nanocrystals with successful interface engineering, and validates their promising use as fuel cell electrocatalyst from both experimental validation and fundamental insights. It may help enlighten the rational design of heterostructured electrocatalysts with regulated multiple active sites. • Stepwise synthesis of trigonal/hexagonal plate-like Pt-on-PdAg hybrid nanostructures is proved. • The density of Pt nano-islands and the overall elemental composition can be tuned. • Interface engineering, tensile strain and multimetallic synergy, contribute to enhanced MOR. • DFT calculations show that MOR mediated by PtAgPd is energetically more favorable. [ABSTRACT FROM AUTHOR]

A novel broadband sensitized near-infrared emitting phosphor, Eu 2 SiS 4 :Er 3+ , was developed as promising solar spectral converter for Si solar cells. Eu 2 SiS 4 :Er 3+ has broadband absorptions ranging from 250 nm to 550 nm which can efficiently facilitate the UV-green part of the solar photon flux spectrum and exhibits intense NIR emission of Er 3+ , perfectly matching the maximum spectral response of Si solar cells. The NIR integrated emission intensity of Eu 2 SiS 4 :0.02Er 3+ is 6.14 times as intense as that of a dual-mode solar spectral converter CaLaGa 3 S 6 O:0.01Ce 3+ , 0.06Pr 3+ . These results demonstrate that Eu 2 SiS 4 :Er 3+ phosphor is a promising candidate used as solar spectral converter. [ABSTRACT FROM AUTHOR]

Novel double perovskite Sr 2 InTaO 6 :Sm3+ phosphors were synthesized by the high-temperature solid-state reaction. The phase purity, luminescent properties, and thermal stability were systematically investigated in this work. When monitoring the emission peak at 649 nm, Sr 2 InTaO 6 :Sm3+ phosphors present an absorption band due to the O2−→Sm3+ charge transfer. Under 407 nm excitation, Sr 2 InTaO 6 :5 mol%Sm3+ phosphor presents four emission peaks at 565, 603, 649, and 717 nm corresponding to the electron transition from 6G 5/2 level to 6H 5/2 , 6H 7/2 , 6H 9/2 and 6H 11/2 levels, respectively. The best doping concentration of Sr 2 InTaO 6 : x Sm3+ is optimized as x = 5 mol%. The chromaticity coordinates of Sr 2 InTaO 6 : x Sm3+ show high color stability and are located in the orange-red region. The residual luminescence intensity at 480 K reaches 86.64%, proving it has excellent thermal stability. Internal quantum efficiency (IQE) is measured as 67.1%. The prepared WLED (white light emitting diode) has a low correlation color temperature (CCT = 4853 K) and an excellent color rendering index (CRI, R a = 93) with CIE (Commission International de L′ Eclairage) coordinates (0.346, 0.349). Therefore, Sr 2 InTaO 6 :Sm3+ phosphors have excellent luminescent properties and promising application prospects. [ABSTRACT FROM AUTHOR]

Plasmonic semiconductor nanomaterials have been widely accepted as promising candidates for photothermal conversion, while the efficiency is yet to optimize. Herein, we report a facile synthesis of Au@Cu x O mesoporous nanospheres anchored with branched Ag nano-islands on the surface and explore their applications as photothermal conversion agent. Due to the intimate hybridization of two materials, the Au@Cu x O-Ag hybrid nanocomposites display a unique dual-plasmonic absorption that covers the visible-NIR range, benefiting the utilization efficiency of light energy. The synthesis is realized by reacting Au@Cu x O with Ag+, the galvanic replacement reaction between them enables a preferential depletion of Cu phase, leaving Ag and Cu 2 O as dominate crystal phases. The resulting hybrid nanocomposites are featured with a core-shell structure but incomplete coverage, as well as the mesoporous interior and dendritic outer shell. In addition to the enhanced photothermal conversion efficiency, the current nano-hybrids show excellent structural stability and no decay in conversion after five successive rounds of measurement. The advantages in both morphological and electronic structure aspects are discussed. The present study validates the promising synergetic use of distinct hot charge carriers originating from metal and semiconductor that are photoexcited in the same hybrid nanoparticle for photothermal conversion, shedding light on rational design of photothermal materials based on metal-semiconductor hybrid nanocomposites. Au@Cu x O mesoporous nanospheres anchored with branched Ag nano-islands are successfully prepared with dual plasmonic absorptions covering the vis-NIR region, exhibiting improved photothermal conversion efficiency and cycling stability. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, novel garnet-type yafsoanite tellurate Ca 3 Zn 3 (TeO 6) 2 :Sm3+ phosphors are successfully synthesized using the traditional high-temperature solid-state reaction. The phase purity of the obtained phosphors is analyzed by X-ray diffraction and Rietveld refinement studies. Morphological variations are also observed with the different concentrations of Sm3+ ions substitution, which is analyzed using Scanning Electron Microscopy (SEM). The photoluminescent properties of the phosphors are systematically investigated. Results show that the samples display the strongest emission peak at 612 nm under the near-ultraviolet (n-UV) 409 nm excitation. This peak can be ascribed to the 4G 5/2 → 6H 7/2 transition of Sm3+. The Ca 3 Zn 3 (TeO 6) 2 :Sm3+ phosphor shows a high color purity, exhibits excellent thermal stability and good color drifting resistance. Furthermore, red and white light-emitting diodes have been successfully prepared. The white light-emitting diodes (w-LEDs) demonstrates a high color rendering index (CRI, R a) and low correlated color temperature (CCT). This study introduces a new orange-red-emitting phosphor and discusses its application in herb-growth w-LEDs. [ABSTRACT FROM AUTHOR]

A novel single-phase KCa 2 Nb 3 O 10 :Dy3+ yellow-emitting phosphor can be efficiently excited under 388 nm irradiation. [Display omitted] • KCa 2 Nb 3 O 10 :Dy3+ phosphors have been firstly synthesized using the molten-salt method. • The KCa 2 Nb 3 O 10 :Dy3+ product shows excellent thermal stability with high temperature quenching temperature. • The KCa 2 Nb 3 O 10 :Dy3+ product shows rich UV excitation band and yellow light emission. • The CIE color coordinates of prepared KCa 2 Nb 3 O 10 :Dy3+ phosphors change slightly. A series of Dy3+ doped KCa 2 Nb 3 O 10 niobate phosphors that generated yellow emission was prepared using the molten-salt method. The crystal structure, X-ray diffraction (XRD), optimal concentration, photoluminescence excitation/emission (PLE/PL), and luminescent stability of the prepared phosphors were exhaustively studied. The KCa 2 Nb 3 O 10 lattice has a perovskite-like structure, which possesses the Cmcm (No.63) space group. The KCa 2 Nb 3 O 10 :Dy3+ phosphors can be efficiently excited by n -ultraviolet (n -UV) excitation of 388 nm. Besides, KCa 2 Nb 3 O 10 :Dy3+ phosphors can emit three dominant peaks centered at 486, 577, and 662 nm, which are ascribed to the 6H J /2 (J = 15/2, 13/2, and 11/2) transitions, respectively. The optimum doping concentrations of Dy3+ ions in the KCa 2 Nb 3 O 10 host are determined to be 0.02 mol. The thermal-quenching temperature (T 0.5) for the KCa 2 Nb 3 O 10 :0.20Dy3+ sample is estimated to be above 500 K, and the calculated activation energy (E a) is 0.29 eV. Furthermore, the Commission International de I'Eclairage (CIE) color coordinates of prepared KCa 2 Nb 3 O 10 :Dy3+ phosphors change slightly. KCa 2 Nb 3 O 10 :Dy3+ phosphors possess good color purity, color stability, and low correlated color temperature (CCT). All results indicate that the KCa 2 Nb 3 O 10 :Dy3+ phosphors are suitable for white light-emitting diodes (w-LEDs) applications. [ABSTRACT FROM AUTHOR]

• A facile method for fabrication of AuAg alloy nanoplates with controlled elemental compositions was developed. • They were characterized with a unique morphology of wavy nanoplate, together with sub-15 nm in thickness. • Tunable LSPR properties and satisfying photothermal performance were demonstrated. Gold-silver alloy wavy nanoplates with tunable elemental compositions are successfully prepared, exhibiting strong NIR absorbance and excellent photothermal properties. [Display omitted] We report a facile synthesis of AuAg alloy nanoplates in high purity, together with tunable elemental compositions and uniformity in size and morphology. The success of current work relies on the one-pot co-reduction of Au and Ag precursor in an ice-water bath with the presence of octadecyltrimethylammonium chloride (OTAC) as a capping agent. With the increase in Ag content, the localized surface plasmon resonance (LSPR) of AuAg alloy nanoplates exhibited a noticeable blue-shift from near-infrared (NIR) to visible region. Thanks to the well-defined NIR LSPR properties and broad spectral range, the current products exhibit a remarkably integrated high-quality photothermal feature as well as the efficient photothermal conversion. Meanwhile, the current AuAg alloy nanoplates demonstrate satisfying photothermal stability verified via continuous exposure and cyclic irradiation by an 808-nm laser. The present study offers a facile route to the preparation of two-dimensional AuAg alloy nanocrystals with tunable elemental compositions and validates their excellent responses towards photothermal measurements, which could find promising use in photothermy-based diagnosis and therapy. [ABSTRACT FROM AUTHOR]

Abstract: A new series of blue-emitting Ce3+-doped CaLaGa3S7 thiogallate chalcogenide phosphors were synthesized by a solid-state reaction method. Their luminescence properties were investigated by photoluminescence excitation, emission spectra and lifetime. The critical dopant concentration was found to be 0.15mol of Ce3+ (R c =15Å) and the fluorescence lifetime of Ce3+ in CaLaGa3S7:0.15 Ce3+ was 12.9ns. The blue-emitting LED was fabricated by combining an InGaN chip (395nm) with a CaLaGa3S7:Ce3+ phosphor. The CIE chromaticity coordinates of the blue LED were calculated to be (0.14, 0.23). [Copyright &y& Elsevier]

Abstract: An intense green phosphor, LiSrPO4:Eu2+, Tb3+, was synthesized by high temperature solid-state reaction. The photoluminescence excitation and emission spectra, the lifetime and concentration effect are investigated in detail. The results show that an efficient non-radiative energy transfer from Eu2+ to Tb3+ occurs and its efficiency is about 66.4%. Tb3+ ions give an intense green emitting light by a strong excitation band of Eu2+ ions at 280–410nm, matching well with the dominant emission band of (n)-UV (350–420nm) LEDs. A phosphor-converted green LED was fabricated by coating the LiSrPO4:Eu2+, Tb3+ phosphor onto (n)-UV chip emitting at 370nm. These results demonstrate that Tb3+ ion with low 4f–4f absorption efficiency in (n)-UV region can play a role of activator in narrow green-emitting phosphor potentially useful in (n)-UV GaN-based LED through efficient energy feeding by allowed 4f–5d absorption of Eu2+ with high oscillator strength. [Copyright &y& Elsevier]