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A novel Y2CaHfScAl3O12:Cr3+,Yb3+ NIR phosphor and application demonstration in the fields of information encryption and non-invasive detection.

Different energy transfer paths of SNGP:Cr3+,Ln3+ contribute to the versatility of phosphors.

A series of o-phenylenediamine bridged tris(phenolate) ligand-stabilized rare-earth metal complexes were synthesized and characterized. Lanthanum (complex 1), neodymium (complex 2tBu), and yttrium (complex 3) complexes stabilized by ligand of bulky tert-butyl substituents are mononuclear, whereas neodymium complexes 2Me and 2Cl bearing smaller methyl and chloro substituents are dinuclear, respectively. They were applied in the alternating copolymerization of CO2 and cyclohexene oxide. The addition of benzyl alcohol is beneficial to improving yields (up to 86%) and selectivity of poly(carbonate) (up to 99%). Stoichiometric reaction of benzyl alcohol with rare-earth metal complexes 1 and 2tBu results in formation of complexes 4 and 5 as dinuclear complexes with benzyl alcohol coordination, which was confirmed via single crystal X-ray diffraction analysis, and nuclear magnetic resonance (NMR) spectroscopy (for 4). Complex 5 shows equally good activity and selectivity of that of complex 2tBu and benzyl alcohol, consolidating that complex 5 is indeed generated during polymerization. The neodymium tris(phenolate) 5 is one of the few examples of rare-earth metal complex as a single-component initiator for copolymerization of epoxide and CO2. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry analysis proves benzyloxy group as the chain end. 1H NMR monitoring suggests that the insertion of CO2 may be the first step in the growth of the polymer chain.

For inorganic luminescent materials with activators, the energy yield is usually observed to decrease with an increase in activator concentration, which is known as the concentration quenching effect. To inhibit this phenomenon, a common strategy is to increase the distance between activators. Most previous reports have focused on the three-dimensional crystal lattice, and there have been few reports about two-dimensional layered structure. Herein, we synthesized a novel Cr

Exploiting efficient and recyclable photocatalysts is a vital matter for environmental purification. Herein, cerium vanadate (CeVO4) sub-microspheres and silver nanowire (AgNW)@CeVO4 with core-shell architecture as photocatalysts are rationally constructed by hydrothermal approach. The AgNW@CeVO4 photocatalyst obtained by depositing CeVO4 on the surface of Ag NWs possess one dimensional continuous structure, which expand the optical absorption range and reduce the band gap of CeVO4 photocatalyst. Moreover, the resultant AgNW@CeVO4 photocatalyst demonstrates superior photocatalytic performance in the degradation of rhodamine B, methylene blue, and 4-nitrophenol pollutants upon solar light irradiation, compared with pure CeVO4. The excellent photocatalytic activity can be ascribed to the introduction of Ag NWs, which afford rapid charge transport channels and reservoir for the electrons in the AgNW@CeVO4 heterostructure to promote separation of electron–hole pairs. The first-principles investigations reveal increase of adsorption energy of oxygen molecules on the CeVO4 surface with the presence of Ag. Meanwhile, Ag NWs can further improve the photocatalytic efficiency of the AgNW@CeVO4 based on the plasmonic effect. More importantly, the good structural stability and recyclability of AgNW@CeVO4 are observed due to the strong synergistic effect, which ensures long-term usability of photocatalyst and great promise in water purification. This work can offer valuable reference into designs and construction of Ce-based heterojunction photocatalysts for environmental remediation.

A new phosphor with ultra-narrow emission band, high thermostability and a rigid net structure similar to benzene ring was investigated, which has potential applications in pc-LED for plant growth.

A red-emitting Eu3+-doped LiYO2 phosphor with excellent luminescence properties was prepared by solid phase reaction, showing potential in high-quality white-light-emitting diodes.

In this work, we prepared a new orange-red phosphor Li2La1-xTiTaO7:xSm3+ (abbreviated as LLTT:Sm3+) for white light-emitting diodes (w-LEDs). Its crystal structure, microstructure, photoluminescence characteristics, luminescent lifetime and thermal quenching properties...

In this paper, a novel Bi3+-activated Ca2LuZrScAl2GeO12 (CLZSAG) phosphor with a garnet structure was prepared by the high temperature solid-state method. There are two kinds of luminescent centers in CLZSAG:Bi3+...

Lanthanide-doped Na2MgScF7 was obtained by combining hydrothermal and high-temperature solid-state reactions, and applied to multicolor anti-counterfeiting.

Non-rare earth doped oxide phosphors with far-red emission have become one of the hot spots of current research due to their low price and excellent physicochemical stability as the red component in white light-emitting diodes (W-LEDs) and plant growth. Herein, we report novel Mn

Co(II) complexes 1-3 bearing amine-bridged bis(phenolato) complexes have been synthesized through reactions of bis(phenols) with CoCl2 or Co(OAc)2. Oxidation of the Co(II) complex with air resulted in partial oxidation, generating mixed valence Co(II/III) complexes 4 and 5. In addition, due to the presence of alkali compounds (KOAc and NaOMe), 4 and 5 formed as Co-alkali metal heterometallic complexes, which are the first example of mixed valence Co(II/III)-M(I) (M = K or Na) complexes. Complexes 1-5 showed good activity in the cycloaddition of epoxides and CO2 under atmospheric pressure, generating cyclic carbonates in 40-99% yields. Co(II/III)-Na(I) complex 5 performed better in reactions of bulkier substrates, underlining the enhanced activity of mixed valence Co-alkali metal heterometallic complexes. On the contrary, complex 5 showed limited activity in copolymerization of epoxide and CO2.

Due to the diversity of structure and composition and the unique coordination environment, nitride materials enable the doped activator ions to possess compelling luminescence characteristics, such as rich emission colors, favorable stability and tunable emission spectra. Here, novel SrLuSi

The solar spectral converters mainly involve the energy transfer between two codoped ions. Here, we report a series of Ce3+, Cr3+, Ln3+ (Ln = Yb, Nd, Er) tridoped Gd3Sc2Ga3O12 (GSGO) phosphors with improved absorption and increasing near infrared (NIR) emission. We observed the multiple energy transfer behaviors of Cr3+→Ln3+, Ce3+→Ln3+, Ce3+→Cr3+, and Ce3+→Cr3+→Ln3+ in GSGO matrix. When Ce3+ is introduced into the GSGO:Cr3+,Ln3+ phosphors, the energy transfer of Ce3+→Cr3+→Ln3+ has been realized by utilizing the energy transfer bridge of the Cr3+ ion. Consequently, GSGO:Ce3+,Cr3+,Ln3+ can absorb almost all ultraviolet and visible (UV–Vis) light and produce strong NIR light thanks to the synergistic effect of Ce3+→Cr3+→Ln3+, improving the photovoltaic conversion efficiency of c-Si solar cells. Our results show that the prepared GSGO:Ce3+,Cr3+,Ln3+ have the potential application in the solar spectral material for c-Si solar cells. Meanwhile, the strategy of multiple energy transfers gives a new way to design the spectral conversion materials with wider absorption for c-Si solar cells.

Gd2GaSbO7:Cr3+,Yb3+ phosphors with efficient broadband NIR emission were prepared by a solid-state reaction. Under the excitation of 448 nm, the Gd2GaSbO7:Cr3+ (GGS:Cr3+) phosphor exhibits a broadband NIR emission band centered at approximately 770 nm with a full width at half maximum (FWHM) of 160 nm. In addition, Yb3+ codoping can distinctly improve the photoluminescence properties of the GGS:Cr3+ phosphor, leading to broadening of the FWHM and greatly enhancing the thermal stability of the phosphor. Moreover, the energy conversion process of Cr3+ → Yb3+ ions was analyzed in detail, demonstrating that the energy transfer mechanism conformed to electric dipole-dipole interaction. The NIR pc-LEDs assembled with the GGS:Cr3+ phosphor and blue LED chips possessed a maximum NIR output power of ∼21 mW at 100 mA driving current, indicating promising applications of the synthesized phosphor in NIR pc-LEDs.

A variety of Bi3+-activated and Bi3+-Eu3+ codoped Y3GaO6 phosphor samples were obtained by solid-state reaction. The phase purity and crystal structure of the specimens were characterized via powder X-ray diffraction (XRD) analysis and Rietveld refinement. For the single Bi3+-doped Y3GaO6 phosphor, two different PL peaks at 410 and 595 nm were obtained, resulting from the two different Bi3+ sites occupied. The site occupation is driven by Bi3+ ion concentration. There is an energy transfer from the Bi3+ to Eu3+ ions in the YGO:Bi3+,Eu3+ phosphors. Besides, the energy transfer mechanism, efficiencies, quantum efficiency and thermal stability have been discussed in detail, demonstrating that the sample possesses high quantum efficiency and good thermal stability. The high color-rendering index Ra (92.9, and 81.6) and low CCT (3286 K, and 3904 K) of the white light-emitting diodes (WLEDs) clearly indicate that these samples are promising candidates for WLEDs.

Novel single-doped and codoped SrGd2Al2O7-based (SGA) phosphors with tunable emission were synthesized via the solid-state reaction approach. The optimal SGA:0.0008Mn4+ phosphor presents an emission band peaking at 709 nm and shows great red luminescence properties. With the incorporation of Nd3+/Yb3+ into SGA:0.0008Mn4+, an efficient energy transfer Mn4+ → Nd3+/Yb3+ was observed. When Nd3+ and Yb3+ were codoped into SGA:0.0008Mn4+, an energy transfer mechanism from Mn4+ to Nd3+ to Yb3+ was found on the basis of the energy transfer mediation of Nd3+ connecting the Mn4+ and Yb3+ luminescent centers. It results in a strong near-infrared emission in the spectral region of high response of c-Si solar cells, which suggests a potential approach to improve the energy conversion efficiency of c-Si solar cells. The findings offer a novel route to design new down-conversion luminescent materials for the c-Si solar cells.

Four homodinuclear rare earth metal (RE) complexes 1-4 bearing a multidentate diglycolamine-bridged bis(phenolate) ligand were synthesized. In addition, seven heterobimetallic RE-Zn complexes 5-11 were prepared through a one-pot strategy. In these heterobimetallic complexes, two RE centers are bridged by either Zn(OAc)2 or Zn(OBn)2 moieties. All complexes were characterized by single crystal X-ray diffraction, elemental analysis, IR spectroscopy, and multinuclear NMR spectroscopy (in the case of diamagnetic complexes 1, 4, 7 and 11). Moreover, the multi-nuclear structures of complexes 4 and 11 in solution were also studied by 1H DOSY spectroscopy. These complexes were applied in catalyzing the coupling reaction of carbon dioxide (CO2) with epoxides. Zn(OAc)2- and Zn(OBn)2-bridged heterobimetallic complexes showed comparable catalytic activities under ambient conditions and were more active than monometallic RE complexes. Significant synergistic effect in heterobimetallic complexes is observed. Mono-substituted epoxides were converted into cyclic carbonates under 1 atm CO2 at 25 °C in 88-96% yields, whereas di-substituted epoxides reacted under 1 atm CO2 at higher temperatures in 40-80% yields.

Dual-emitting and thermochromic manganese ion single doped ZnGa2-yAlyO4 phosphors were prepared by solid-state reaction. The regulation of the valence state and the luminescent properties, especially the luminescent thermal stability of manganese ions in ZnGa2-yAlyO4, are discussed in detail. When excited by ultraviolet (UV) light, the emission spectra of ZnGa2O4:Mn2+,Mn4+ present an ultranarrow green emission band at 503 nm with a fwhm of 22 nm, which derives from the Mn2+ ions formed by the self-reduction of doped Mn4+, and a red emission band of the Mn4+ ions at 669 nm. In addition, a ZnGa2-yAlyO4:Mn2+,Mn4+ solid solution was designed and synthesized by Al3+ replacing Ga3+. The doping of Al3+ effectively inhibited the degree of Mn4+ self-reduction to Mn2+, thus realizing the regulation of valence state of manganese ions. Interestingly, the thermal stability of luminescence shows that the response of Mn2+ and Mn4+ to temperature is obviously different in ZnGa2-yAlyO4, implying the potential of the prepared phosphors as optical thermometers. Subsequently, three kinds of optical thermometers with superior color discrimination and high relative sensitivity (Sr) based on the fluorescence intensity ratio (FIR) technique were realized in 100-475 K. The Sr value of ZGO:0.005Mn/ZGA0.5O:0.005Mn/ZGAO:0.005Mn phosphors can be as high as 4.345%/4.001%/3.488% K-1 (at 350/325/400 K), reflecting the great potential of ZnGa2O4:Mn2+,Mn4+ for optical thermometry applications.

A series of rare-earth (RE) metal complexes (Y, Sm, Nd, and La) stabilized by polydentate N-methylethylenediamine-bridged tris(phenolato) ligands was synthesized and characterized. Lanthanum comple...

Novel orange-red-emitting phosphors Ca3M2Ge3O12:Mn2+,Mn4+ (M = Al, Ga) with sufficient red light component were developed, and their lattice occupancy and luminescent properties of different color ...

Gd3Ga5–x–δAlx–y+δO12:yMn solid solutions with improving luminescence properties were prepared via cation substitution and a controllable Mn valence state. The abnormal autoreduction from Mn4+ to Mn...

Non-invasive theranostics that integrate the advantages of multimodality imaging and therapeutics have great potential in the field of biomedicine. Herein, a new nanohybrid based on Bi2 Se3 -conjugated upconversion nanoparticles (UCNPs) has been successfully developed through a simple in situ growth strategy. Under 808 nm near-infrared laser irradiation, the UCNPs can emit bright visible light, whereas the Bi2 Se3 nanomaterial exhibits efficient photothermal conversion capacity. Moreover, the as-synthesized UCNP-Bi2 Se3 nanohybrid exhibits efficient cell upconversion luminescence (UCL), reasonable CT imaging, and admirable cancer cell ablation capacity, further emphasizing the efficiency of this strategy for simultaneous UCL imaging and photothermal therapy. The designed theranostic strategy guided by dual-modal imaging endowed with real-time dynamic monitoring, remote controllability, and non-invasiveness makes the UCNP-Bi2 Se3 nanohybrid an ideal candidate for non-invasive multimodal imaging-guided photothermal therapy for the precise diagnosis and treatment of cancer.

Designing the synthesis of inorganic micro/nanocrystals that are hard to get through conventional synthetic routes remains a challenging issue. Herein, we developed a novel in situ topotactic transformation synthetic strategy towards Y2O2S micro/nanocrystals based on high topotactic structural matching with the crystalline relationship between [001]Y4O(OH)9NO3//[001]Y2O2S and [001]LYH//[010]Y2O2S (LYH is Y2(OH)5NO3·nH2O). We have contrastively elucidated the in situ topotactic transformation mechanism from the crystal structure point of view and found that the microscopically topotactic structural matching in structural anisotropy and atomic arrangement facilitates the Y4O(OH)9NO3 → Y2O2S and LYH → Y2O2S transformation processes, respectively. Interestingly, the morphology contours were maintained well although a high degree of crystal lattice rearrangement was involved during the topotactic transformation process, which contributed to two brand-new morphologies that were unavailable by the conventional synthetic route (hexagonal microprism and quadrangle nanoplate) for Y2O2S. Besides, we also selected amorphous Y(OH)CO3 sub-microsphere as a precursor to comparatively study the structural topotactic transformation. Furthermore, the luminescence properties of the as-prepared micro/nanophosphors were emphasized by featuring the multicolor emissions by downshifting (Eu3+, Tb3+) and upconversion (Yb3+/Er3+, Yb3+/Tm3+) luminescence. Our study may bring a new direction of thought for the targeted synthesis of inorganic micro/nanocrystals that are difficult to get via conventional synthetic routes.

The facile and green synthesis of novel structured inorganic micro/nanocrystals is prospective in the field of functional materials. Herein, uniform porous/hollow YVO4 submicro-ellipsoids were developed via a surfactant-free and one-pot aqueous-based strategy using Y2(OH)5NO3·nH2O (LYH) as a precursor. We propose a possible morphological evolution mechanism related to quick assembly, followed by the Ostwald ripening process based on a series of time-dependent investigations. Besides, we propose a possible transformation process from LYH to YVO4 on the basis of the high structural matching between [001]LYH and [110]YVO4. Furthermore, we found that the successful synthesis of porous/hollow YVO4 ellipsoids remarkably depended on the precise tuning of the reaction parameters (reaction temperature, pH value, and Na+ concentration). In addition, multicolor down-conversion emissions were realized via lanthanide ion (Ln3+: Eu3+, Sm3+, and Dy3+) doping. The as-synthesized porous/hollow products may be ideal candidates for bio-/energy-related applications.

The design and synthesis of responsive inorganic nanocapsules have attracted intensive research interest in cancer treatment. The combination of non-invasive diagnosis and chemotherapy into a single theranostic nanoplatform is prospective in the biomedical field. In this work, a polyacrylic acid (PAA)-functionalized porous BiF3:Yb,Er nanocarrier was constructed via a straightforward one-pot solvothermal strategy. Compared with the undoped BiF3 sub-microspheres, the lanthanide ion (Ln3+) doping endowed the BiF3 material with a smaller size and increased BET specific surface area and pore volume, which make it suitable as a drug carrier. It was found that the synthesized nanomaterial could effectively relieve the side effects of doxorubicin (DOX) and exhibited pH-dependent DOX loading and release. Its satisfactory biocompatibility and efficient tumor inhibition were emphasized by a series of in vitro/in vivo experiments. In addition, the synthesized nanomaterial exhibited favorable CT contrast efficacy due to the excellent X-ray attenuation coefficient of Bi. Moreover, characteristic upconversion luminescence and temperature sensing in a wide temperature range were realized over the synthesized BiF3:Yb,Er sample. Therefore, carboxyl-functionalized BiF3:Yb,Er can be expected to be an ideal candidate in the fabrication of temperature sensing and multifunctional theranostic nanoplatforms.

A series of CaAl6Ga6O19:Cr3+,Ln3+ (Ln = Yb, Nd, and Er) novel near-infrared (NIR) emitting phosphors were prepared via a high-temperature solid-state reaction. The luminescence spectra and decay lifetimes of these samples were measured to prove the energy transfer process from the Cr3+ to Ln3+ ions. The CaAl6Ga6O19:Cr3+,Ln3+ (Ln = Yb, Nd, and Er) phosphors can efficiently convert the short-wavelength sunlight in the near-ultraviolet and visible (UV-Vis) regions into near-infrared emission, which matches the higher sensitivity region of the c-Si solar cells. The maximal energy transfer efficiencies of CaAl6Ga6O19:Cr3+,Ln3+ (Ln = Yb, Nd, and Er) were 25.84%, 73.90%, and 29.46%, respectively. Our results show that the CaAl6Ga6O19:Cr3+,Ln3+ (Ln = Yb, Nd, and Er) phosphors have potential applications as luminescent downshifting convertors for enhancing the photoelectric conversion efficiency of the c-Si solar cells.

A series of novel Y3Ga5O12:Bi3+,Mn2+ phosphors with controllable luminescence have been synthesized and their photoluminescence characteristics have been studied in detail with the purpose of developing a single-component white light-emitting phosphor suitable for pc-WLEDs. The Bi3+ singly-doped phosphor shows an intense blue–green emission, while the Mn2+-doped phosphor presents a narrow red emission with a FWHM of 59 nm, which is comparable to the previously reported nitride red phosphor Ca[LiAl3N4]:Eu2+. When Bi3+ and Mn2+ were co-doped into the Y3Ga5O12 matrix, effective energy transfer from the Bi3+ to Mn2+ ions was observed. Subsequently, a single-component warm white light-emitting phosphor was obtained by adjusting the doping ratio of Bi3+ and Mn2+ and by utilizing the energy transfer from the Bi3+ to Mn2+ ions. Moreover, the thermal quenching properties show that the prepared Y3Ga5O12:Bi3+,Mn2+ samples possess good thermal stability of luminescence. Finally, a WLED device with a high Ra of 90, a low CCT of 3908 K, and a CIE color coordinate of (0.3503, 0.3158) has been fabricated using the synthesized phosphor. The results indicate that Y3Ga5O12:Bi3+,Mn2+ phosphors are potential candidates as single-component white light emission phosphors applied in WLEDs. Moreover, this strategy is also conducive for the design of novel white light emission phosphors for pc-WLEDs.

A series of solid solution CaAl12-xGaxO19:Mn4+ phosphors were prepared via a high-temperature solid-state reaction. Their structural properties were characterized by X-ray diffraction (XRD) and the luminescence was investigated via photoluminescence spectra. The obtained CaAl12-xGaxO19:Mn4+ phosphor has a strong broad excitation band in the range of 250-550 nm, which can be easily excited by the UV, NUV and blue light, and a broad emission band centered at 655 nm between 600 nm and 800 nm due to the 2Eg → 4A2g transition of the Mn4+ ion. The PL spectra indicate that the intensity of CaAl12O19:Mn4+ can be enhanced when the Ga3+ concentration equals 1. Furthermore, the element mapping, optical properties, thermal stability, fluorescence lifetime and CIE chromaticity reveal that the CaAl12-xGaxO19:Mn4+ phosphors can be considered as potential candidates in indoor plant cultivation.

Gd

Non-rare earth doped oxide phosphors with far-red emission have become one of the hot spots of current research due to their low price and excellent physicochemical stability as the red component in white light-emitting diodes (W-LEDs) and plant growth. Herein, we report novel Mn4+-doped La2CaSnO6 and La2MgSnO6 phosphors by high-temperature solid-phase synthesis and analyzed their crystal structures by XRD and Rietveld refinement. Their excitation spectra consist of two distinct excitation bands with the dominant excitation range from 250 to 450 nm, indicating that they possess strong absorption of near-ultraviolet light. Their emission is located around 693 and 708 nm, respectively, and can be absorbed by the photosensitive pigments Pr and Pfr, proving their great potential for plant growth. Finally, the prepared samples were coated with 365 nm UV chips to fabricate far-red LEDs and W-LEDs with low correlation color temperature (CCT = 4958 K/5275 K) and high color rendering index (Ra = 96.4/96.6). Our results indicate that La2CaSnO6:Mn4+ and La2MgSnO6:Mn4+ red phosphors could be used as candidate materials for W-LED lighting and plant growth.

Controllable synthesis of inorganic functional nano/microcrystals with desired phase/morphology is a focal theme in field of materials science. Herein, a green aqueous-based synthetic route has been developed to prepare uniform Ln3+ (Ln = Eu, Yb/Er, Yb/Tm) doped YOF/Y6O5F8 microcrystals. The phase structure, particle morphologies, and photoluminescence properties were investigated by means of XRD, SEM, TEM, TG, and PL analysis. It is found that the as-synthesized YOF/Y6O5F8 microcrystals are uniform microdiscs with good dispersity and porous properties. The influences of the NH4HCO3/NaF feeding ratio on the phase structure, morphology, and size were investigated in detail. Moreover, the luminescence properties of the YOF:Ln3+ and Y6O5F8:Ln3+ are comparatively investigated via downconversion and upconversion processes from the lattice structure view. This synthetic strategy may provide a feasible and general case for green and controllable synthesis of other uniform inorganic nano/microcrystals.

A series of novel Eu2+/Ce3+/Tb3+ ion doped La8Ca2(Si4P2O22N2)O2-based apatite structure oxynitride phosphors have been synthesized by a solid-state method. The phase purity has been checked by X-ray diffraction (XRD) and the Rietveld method. The photoluminescence excitation (PLE) spectra indicate that the obtained phosphors have broad excitation bands in the n-UV range, which is a favourable property for application as n-UV-WLED phosphors. The concentration quenching has been investigated in detail. The temperature-dependent luminescence and efficiency study shows that the as-prepared phosphors have a good thermal stability and high quantum efficiency. Moreover, a warm white LED device with a low color temperature of 4288 K and a high color rendering index (Ra) of 80.8 has been obtained by coating a La8Ca1.99(Si4P2O22N2)O2:0.01Eu2+ phosphor with a (Sr,Ca)AlSiN3:Eu2+ red phosphor on a n-UV chip. Our results reveal that the La8Ca2(Si4P2O22N2)O2:Eu2+ phosphor is a promising bluish-green phosphor for WLEDs.

Novel La8Ba2(Si4P2O22N2)O2:Eu2+/Ce3+/Tb3+ apatite phosphors with tuneable light emission have been successfully synthesized by the conventional solid-state method. The structural and luminescence properties of the newly obtained samples have been studied systematically. The photoluminescence properties show that the Eu2+-, Ce3+- and Tb3+-doped La8Ba2(Si4P2O22N2)O2 samples have strong absorption in the near ultraviolet (n-UV) region. Under n-UV light irradiation, Eu2+-doped samples exhibit a narrow bluish green emission band peaking at 496 nm with a full width at half-maximum (FWHM) of 55 nm, which is comparable to the commercial blue emitting BaMgAl10O17:Eu2+ (FWHM = 55 nm) phosphor, while La8Ba2(Si4P2O22N2)O2:Ce3+,Tb3+ presents adjustable emission colour from violet to green by adjusting the concentration of Tb3+. The energy-transfer efficiencies and mechanisms have been discussed in detail. The temperature dependent luminescence measurements show that the obtained samples have low thermal quenching. Moreover, a series of white LED devices have been obtained by using the La8Ba1.99(Si4P2O22N2)O2:0.01Eu2+/(Sr,Ca)AlSiN3:Eu2+/(Ba,Sr)SiO4:Eu2+/(Sr,Ba,Ca)10(PO4)Cl2:Eu2+/Sr2SiO4:Eu2+ phosphor blend. By adding the as-prepared narrow bluish-green-emitting La8Ba1.99(Si4P2O22N2)O2:0.01Eu2+ phosphor, the Ra values can increase from 68 to 98, the R9 values increase from 42 to 95, and the corresponding CCT continuously decreases from 6210 to 3086 K, respectively. Our results reveal that the Eu2+, Ce3+ and Tb3+ activated phosphors are promising candidates for WLEDs.

A series of Cr3+-Yb3+/Nd3+/Er3+ codoped LaGaO3 phosphors were synthesized by a traditional solid-state method. The morphology, crystal structure, phase purity, and the luminescence properties of samples were characterized by using X-ray diffraction, Rietveld refinement, field-emission scanning electron microscopy, and photoluminescence. The obtained phosphors exhibit efficient broad absorption in the near ultraviolet and visible (UV-Vis) region and intense near infrared (NIR) emission, due to the energy transfer process from the Cr3+ to Yb3+/Nd3+/Er3+ ions, which match well with the maximum photon flux region of the solar spectrum and the optimal spectral response of the C-Si solar cell. Moreover, we also observed an energy transfer from the Nd3+/Er3+ to Yb3+ ions. The efficiency was investigated and analyzed by the visible and NIR emission spectra and lifetime decay curve and the energy transfer efficiency was as high as 77%. Our results reveal that the Cr3+-Yb3+/Nd3+/Er3+ codoped phosphors are promising materials for enhancing the efficiency of solar cells.

Herein, a novel multifunctional nanoplatform was designed toward multimodality imaging and photothermal therapy (PTT). It was found that Bi nanoparticles could grow in situ on the surface of NaYF4:20%Yb,2%Er@NaYF4:40%Yb@NaGdF4 core-shell nanoparticles (labeled as UCNPs). In this structure, UCNPs were mainly employed as an upconversion luminescence (UCL) imaging agent, whereas the Bi nanoparticles worked as an effective CT imaging and photothermal agent. Importantly, a dense SiO2 shell was employed to protect the Bi nanoparticles from oxidation, and it also endowed the nanoplatform with excellent hydrophilic ability. The effective UCL/CT imaging and PTT performances were emphasized by a series of in vivo experiments, which suggest that the integrated nanoplatform with imaging and therapy functions shows great promise in the biomedical field.

Novel single-doped and codoped SrGd