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Accompanied by internal defect evolution in the perovskite lattice, the naturally formed “hollow” defects and obviously blue-shifted emission of CsEuCl3 nanocrystals were observed.

Mn4+-activated phosphors have become a hotspot in the development of inorganic red phosphors due to the fascinating photoluminescent properties. Herein, the synergetic manipulation of the flux effect and charge compensation was employed to improve the performance of Mn4+-activated CaAl12O19 red phosphors. The crystallinity was improved by appropriate Zn2+-doping, while nonradiative transition between Mn4+ ions is reduced by charge compensation of the formation of Mn4+–Mg2+ pairs with Mg2+ dopants. Thus, the emission of Mn4+-activated CaAl12O19 red phosphors has been remarkably enhanced. The low probability of nonradiative transition between Mn4+ ions was demonstrated by the thermal stability analysis. To depict the luminescent process, the crystal-field strength (Dq), and Racah parameters (B and C) were calculated to determine the sequence of the energy levels. Meanwhile, the warm WLEDs with high CRI and low CCT were obtained using the prepared phosphors as red-emitting composition. Our results clearly suggested that the synergetic strategy by combining the flux effect and charge compensation is an effective method to enhance the luminescence of CaAl12O19:Mn4+, and CaAl12O19:Mn4+/Zn2+/Mg2+ red-emitting phosphors, which have potential application value in warm WLEDs.

In this work, a dual p-n heterojunction of Cu2O/Ni(OH)2/TiO2 with type-II band alignment and matched build-in electric field was fabricated. This dual p-n heterojunction promoted the separation and transfer of charge carriers, which is much more efficient than individual p-n heterojunction. Photocatalytic hydrogen evolution under the simulated sunlight shows a high rate of 6145 μmol g−1 h−1 for Cu2O/Ni(OH)2/TiO2, which is 1.9 and 2.7 times that of Ni(OH)2/TiO2 and Cu2O/TiO2, respectively. The apparent quantum yield of Cu2O/Ni(OH)2/TiO2 is about 20.2% under the irradiation of monochromatic light (λ = 420 nm). The recycling test of hydrogen evolution also verified a high stability for this dual heterojunction. The type-II band alignment and matched build-in electric field was confirmed, which accelerate the migration of charge carriers. The width of space-charge layer was calculated and proved that the p-n junctions in Cu2O/Ni(OH)2/TiO2 are fully-depleted, which largely reduced the bulk recombination of charge carriers. The synergistic effect of the improved visible-light response, type-II band alignment, matched build-in electric field, and fully-depleted space-charge layer contributes to the enhanced photocatalytic hydrogen evolution.

To research and develop the potential red emission phosphors for warm white-light-emitting diodes (WLED), we systematically investigated double alkaline rare-earth molybdates KGd1−xEux(MoO4)2 (0.05 ≤ x ≤ 1) phosphors. The crystal structure, morphology, chemical composition, and photoluminescence properties of the phosphors with different Eu3+ doping concentrations were investigated in detail. The results indicate that Eu3+ doping concentration can affect the crystal structure and morphology of KGd1−xEux(MoO4)2 phosphors. The luminescence performance reveals that KGd1−xEux(MoO4)2 phosphor could emit intense red emission under multiplexed excitations at 362, 382, 394, 465, and 535 nm, which are matched well with the commercial UV, blue and green LED chips. An abnormal quenching behavior was observed in the KGd1−xEux(MoO4)2 phosphors. And the quenching behavior at the excitation of Eu3+–O2− Charge-Transfer band and Eu3+ ions 4f–4f transitions is quite different. Finally, we fabricated a WLED lamp by coating the InGaN blue chip with a mixture of YAG: Ce3+ yellow phosphors and KEu(MoO4)2 red phosphors. The obtained WLED lamps showed warm white light with a lower CCT value (~ 5142 K) than that fabricated without the red phosphors (CCT = 5892 K). These results proved that the KGd1−xEux(MoO4)2 could be a very promising red-emitting phosphor for WLED.

Synergistic the modulation of photon absorption capability and interfacial charge transfer of the photocatalyst are highly required for developing high-performance heterojunction photocatalysts. The ternary CdS-graphene quantum dots-titanate nanotubes (CdS-GQDs-TNTs) nanocomposite have been prepared by an in situ growth method. The physicochemical characterization reveals that the GQDs are firmly decorated on both inner and outer surface of TNT through the formation of Ti–O–C chemical bonding, and CdS QDs are loaded on the outer surface of TNTs through strong interfacial interaction. The intimate integrated CdS-GQDs-TNTs nanocomposite exhibits much superior photocatalytic performance toward H2 production compared with binary GQDs-TNTs and pure TNTs photocatalyst, which can be attributed to the combined interaction of the stronger visible light harvesting, the longer lifetime of photogenerated electron−hole pairs, faster interfacial charge transfer rate, fast and long-distance electron transport pass. The interfacial charge transfer mechanism of CdS-GQDs-TNTs ternary composite are proposed based on photoelectrochemical measurements.

Epitaxial PbTiO3 films with a smooth and dense surface were fabricated by a promising hydrothermal synthesis on an Nb:SrTiO3(100) substrate. The resulting coated substrate was used to fabricate a Pt/PbTiO3/Nb:SrTiO3 heterostructure device. The device exhibited a multilevel storage capacity with an appropriate R OFF / R ON ratio and excellent endurance and retention. An electric conduction analysis indicated that the resistive switching behavior of the device was attributed to the trap controlled space-charge-limited current conduction that was caused by the oxygen vacancies in the PbTiO3 hydrothermal films. The modulation of the Pt/PbTiO3 Schottky-like junction depletion under an applied electric field is thought to be responsible for the resistive switching behavior of the device in the carrier injection-trapped/detrapped process.

The large number of energy levels available to lanthanide ions makes the emission mechanism of lanthanide-doped luminescent materials extremely complicated. Herein, we focus on the discussion and analysis of luminescence manipulation in Gd2O3:Yb3+/Er3+ nanocrystals and systematically investigate ion-ion interaction–induced energy transfer in up- and downconversion processes to shed light on the manipulation mechanism, showing that the luminescence of the above nanocrystals can be controlled by varying the content of Yb3+. Based on Dexter's energy transfer theory and the fact that excitation of Er3+ ions results in the appearance of emission attributed to the 2F5/2→2F7/2 transition of Yb3+ in the near-infrared region (950–1100 nm), this behavior is ascribed to the occurrence of energy transfer from Er3+ to Yb3+.

Tailoring the band gap and understanding the underlying mechanism are important for extending the applications of graphene quantum dots in optoelectronics. In this work, we synthesize fluorinated graphene oxide quantum dots (F-GOQDs) through a photochemical method, and study their optical properties. The obtained F-GOQDs exhibit a maximal blue-shift of photoluminescence (PL) emission of ca. 77 nm compared to that of the graphene oxide quantum dots (GOQDs). The PL shift results from the substitution of the hydroxyls and carbonyls groups with fluorine during the fluorination process, which can tune the band gap of the GOQDs. Density functional theory (DFT) calculations support our proposed mechanism for band gap tuning in the GOQDs through the use of fluorination.

Correction for ‘Enhanced photoluminescence stability and internal defect evolution of the all-inorganic lead-free CsEuCl3 perovskite nanocrystals’ by Yalei Gao et al., Phys. Chem. Chem. Phys., 2022, 24, 18860–18867, https://doi.org/10.1039/D2CP01374F.

A new class of TiO2-doped CeO2 nanorods was synthesized via a modified hydrothermal method, and these nanorods were first used as catalysts for the direct synthesis of dimethyl carbonate (DMC) from CO2 and CH3OH in a fixed-bed reactor. The micromorphologies and physical–chemical properties of nanorods were characterized by transmission electron microscopy, X-ray diffraction, N2 adsorption, inductively coupled plasma atomic emission spectrometry, X-ray photoelectron spectroscopy, and temperature-programmed desorption of ammonia and carbon dioxide (NH3-TPD and CO2-TPD). The effects of the TiO2 doping ratio on the catalytic performances were fully investigated. By doping TiO2, the surface acid–base sites of CeO2 nanorods can be obviously promoted and the catalytic activity can be raised evidently. Ti0.04Ce0.96O2 nanorod catalysts exhibited remarkably high activity with a methanol conversion of 5.38% with DMC selectivity of 83.1%. Furthermore, kinetic and mechanistic investigations based on the initial rate m...

Hierarchical porous carbon (HPC) consists of micropores, mesopores and macrospores which are synthesized by in situ formation of template followed by acid etching. The obtained pores are three-dimensional and interconnected, and evenly distributed in the carbon matrix. By adjusting the ratio of the raw materials, the high specific surface area and large pore volume is afforded. The obtained HPC-3 samples possess graphite flakes and locally graphited-carbon walls, which provide good electrical conductivity. These unique characteristics make these materials suitable cathode scaffolds for Li–S batteries. After encapsulating 61% sulfur into HPC-3 host, the S/HPC-3 composite exhibits excellent cycling stability, high columbic efficiency, and superior rate cycling as a cathode material. The S/HPC-3 composite cathode displays an initial discharge capacity of 1059 mA h g−1, and a reversible capacity of 797 mA h g−1 after 200 cycles at 0.2C. The discharge capacities of the S/HPC-3 composite cathode after every 10 cycles at 0.1, 0.2, 0.5, 1, and 2C are 1119, 1056, 982, 921, and 829 mA h g−1, respectively.

Materials with tunable photoluminescence (PL) are highly desirable. It can lead to important applications such as photodetectors, bio-imaging, and broadband modulators. In this work, nitrogen-doped graphene oxide quantum dots (NGOQDs) were synthesized by hydrothermal method. The microstructures as well as optical properties of NGOQDs were studied. The as-prepared NGOQDs present tunable PL and exhibit a maximal PL blue-shift of ca. 88 nm compared to that of the graphene oxide quantum dots (GOQDs). The observed PL blue-shift of the NGOQDs is attributed to the high content of pyridine-like and pyrrolic-like nitrogen atoms doping in the NGOQDs. Our proposed mechanism for the PL blue-shift of the NGOQDs is supported by density functional theory (DFT) calculations.

Role of microRNA-429 (miRNA-429) in osteogenic differentiation of hADMSCs was elucidated to explore the potential mechanism. Serum level of miRNA-429 in osteoporosis patients and controls was determined by quantitative real-time polymerase chain reaction (qRT-PCR). After H2O2 induction in hADMSCs, cell viability and reactive oxygen species (ROS) level were determined by cell-counting kit (CCK-8) assay and flow cytometry, respectively. Alkaline phosphatase (ALP) activity in H2O2-induced hADMSCs was also detected. The binding condition between miRNA-429 and SCD-1 was verified by dual-luciferase reporter gene assay. Relative levels of osteogenesis-related genes influenced by SCD-1 and miRNA-429 were detected by qRT-PCR. Furthermore, regulatory effects of SCD-1 and miRNA-429 on ALP activity and calcification ability of hADMSCs were evaluated. miRNA-429 was significantly upregulated in serum of osteoporosis patients. During the process of osteogenesis differentiation, H2O2 induction gradually upregulated miRNA-429 in hADMSCs. Overexpression of miRNA-429 markedly reduced ALP activity. Subsequent dual-luciferase reporter gene assay verified that miRNA-429 could bind to SCD-1 and negatively regulated its protein level in hADMSCs. SCD-1 was obviously downregulated in the osteogenesis differentiation of hADMSCs under oxidative stress. Moreover, silencing of SCD-1 suppressed expression of osteogenesis-related gene, ALP activity and calcification ability. Notably, SCD-1 knockdown partially reversed the regulatory effect of miRNA-429 on the osteogenic differentiation of hADMSCs. miRNA-429 suppresses the osteogenic differentiation of hADMSCs under oxidative stress via downregulating SCD-1.

To research and develop potential multifunctional nanoprobes for biological application, lanthanide-doped MCM-41 (Ln-MCM-41, Ln = Gd/Eu) silica nanoparticles with excellent pore structure and optical–magnetic properties were synthesized via a facile and economical sol–gel method. The microstructure and pore distribution of Ln-MCM-41 nanoparticles were obviously affected by the Ln-doping. As the Ln/Si mole ratio increased, the specific surface area and total pore volume of Ln-MCM-41 nanoparticles rapidly decreased. However, the Ln-MCM-41 nanoparticles still retained the typical well-ordered mesoporous structure, and exhibited excellent drug release behavior. Moreover, the drug release rate of Ln-MCM-41 was remarkably pH-dependent and increased gradually upon decreasing pH. Additionally, these nanoparticles also exhibit considerable photoluminescence properties, living cells photoluminescence imaging in vitro, and paramagnetism behavior at room temperature due to the Ln3+-ions doping. Our research shows the possibility of our Ln-MCM-41 nanoparticles as multifunctional nanoprobes for application in bioseparation, bioimaging, and drug delivery.

In this review, state-of-the-art polymer electrolytes are discussed with respect to their electrochemical and physical properties for their application in lithium polymer batteries. We divide polymer electrolytes into the two large categories of solid polymer electrolytes and gel polymer electrolytes (GPE). The performance requirements and ion transfer mechanisms of polymer electrolytes are presented at first. Then, solid polymer electrolyte systems, including dry solid polymer electrolytes, polymer-in-salt systems (rubbery electrolytes), and single-ion conducting polymer electrolytes, are described systematically. Solid polymer electrolytes still suffer from poor ionic conductivity, which is lower than 10−5 S cm−1. In order to further improve the ionic conductivity, numerous new types of lithium salt have been studied and inorganic fillers have been incorporated into solid polymer electrolytes. In the section on gel polymer electrolytes, the types of plasticizer and preparation methods of GPEs are summarized. Although the ionic conductivity of GPEs can reach 10−3 S cm−1, their low mechanical strength and poor interfacial properties are obstacles to their practical application. Significant attention is paid to the incorporation of inorganic fillers into GPEs to improve their mechanical strength as well as their transport properties and electrochemical properties.

Highly efficient H2 production from water splitting has been achieved by N-doped titanate nanotubes (N-TNTs) decorated with graphene quantum dots (GQDs) in this work. In order to promote charge carrier transmission at the interface, a facile and environmentally friendly in situ growth method was employed to construct a strongly coupled N-TNT/GQD composite photocatalyst. The results revealed that N atoms were effectively doped into the crystal lattice of the TNTs in the form of both interstitial N and substitutional N, and the GQDs were decorated onto both the inner and outer surfaces of the N-TNTs through the formation of Ti-O-C chemical bonds. Photoelectrochemical measurements proved that, in N-TNT/GQD composite, N-doping can extend light response to the visible-light range, and the coupling with GQDs not only enhanced visible-light absorption, but also promoted interfacial charge carrier transfer. Due to the synergistic effect between N-doping and GQD coupling, the closely integrated N-TNT/GQD composite exhibits a much superior photocatalytic H2 production performance under UV-vis irradiation, being 2.1 times higher than that of pure TNTs.

Titania nanotube-Cd0.65Zn0.35S nanocomposite (Cd0.65Zn0.35S-TiO2) was synthesized from titanate nanotubes for ion change of Cd2+ and Zn2+ followed by hydrothermal sulfuration treatment using thiourea as sulfur source. The Cd0.65Zn0.35S-TiO2 with enhanced crystallinity of TiO2 nanotube can be obtained by increasing hydrothermal temperature from 90 °C to 120 °C. And further increasing hydrothermal temperature to 150 °C, TiO2 nanotubes collapse and transform into irregular shaped particles. The photocatalytic activity for hydrogen production of the prepared Cd0.65Zn0.35S-TiO2 with different hydrothermal temperature was investigated under visible-light irradiation. The result shows that the Cd0.65Zn0.35S-TiO2 with hydrothermal temperature of 120 °C presents the highest hydrogen evolution rate and photostability, which can be attributed to a rapid charge transfer at the interface between Cd0.65Zn0.35S and TiO2 nanotube due to the increased crystallinity and unique 1-D nanotubular structure of TiO2.

Rutile TiO 2 nanorod arrays (TNRs) were achieved by hydrothermal process on TiCl 4 pretreated Ti foil. Subsequently, TNRs were hydrothermally etched in HCl solution to form hollow TiO 2 nanorod arrays (H-TNRs). The TiCl 4 pretreatment plays key roles in enhancement of Ti foil corrosion resistance ability and crystal nucleation introduction for TNRs growth. TNRs with desired morphology can be obtained by controlling TiCl 4 concentration and the amount of tetrabutyl titanate (TTB) accordingly. TNRs with the length of ~1.5 μm and diameter of ~200 nm, obtained on 0.15 M TiCl 4 pretreated Ti foil with 0.6 mL TTB, exhibits relatively higher photocurrent. The increased pore volume of the H-TNRs has contributed to the increased surface area which is benefit for Dye-Sensitized Solar Cells (DSSC) application. And the 180 °C-H-TNRs photoanode obtained from the 0.15-TiCl 4 -TNRs sample demonstrated 128.9% enhancement of photoelectric efficiency of DSSC compared to that of the original TNR photoanode.

TiO 2 nanotubes were prepared by hydrothermal treatment of TiO 2 powder in NaOH aqueous solution and then calcined at various temperatures. The post-calcination treated TiO 2 nanotubes were decorated with CdS by wetness impregnation and subsequently sulfurization to fabricate CdS/TiO 2 composites. The photocatalytic performance of CdS/TiO 2 composites toward hydrogen production from water splitting was investigated. The results show that the calcination temperature of TiO 2 nanotubes has a significant effect on the photocatalytic performance of CdS/TiO 2 . With the increase of calcination temperature from 300 to 500 °C, the crystallinity of TiO 2 nanotubes is increased resulting in the enhanced photocatalytic performance of CdS/TiO 2 . When the calcination temperature is higher than 500 °C, TiO 2 nanotubes gradually transform into nanorods and finally completely collapse, which leads to the decrease of photocatalytic performance of CdS/TiO 2 . The CdS/TiO 2 composite with TiO 2 nanotubes calcined at 500 °C exhibits the highest hydrogen evolution rate, which could be attributed to its 1 D nanotubular structure and good crystallinity.

Nb-doped TiO2 nanoparticles were prepared by hydrothermal treatment of titanate nanotubes in niobium oxalate aqueous solution. The effect of Nb doping and rutile content on the photoelectrochemical performance based on TiO2 powder electrodes was investigated. The results show that Nb-doped TiO2 with a small amount of rutile exhibits the enhanced photoelectric conversion efficiency for dye-sensitized solar cell. The highest photoelectric conversion efficiency of 8.53% is obtained for 1% Nb–TiO2 containing a small amount of rutile. When a small amount of rutile contained in 2% Nb–TiO2, a higher photoelectric conversion efficiency of 8.77% is achieved.

Titanate nanotubes (TNTs) were coupled with amino-propyl-triethoxy silane (KH550) and calcinated at 400 °C, then the silica modified titanate nanotubes (STNTs) were prepared and used as the support of a Pd catalyst by the method of wet-impregnation. The catalyst was characterized with XRD, Raman spectra, TEM, XPS, and H2-TPR/TPD. The silica modification could effectively resist morphology collapse and crystallization of TNT during calcination, and preserve the high surface area of the TNT support, which contribute to the high metal dispersion of loaded Pd. Moreover, the introduced silica could strengthen the metal–support interaction, causing an electronic effect that facilitates the reduction of Pd ions. The Pd/STNT showed 3 times and 2.5 times higher activity than those of commercial Pd/C and unmodified Pd/TNT catalysts towards the selective hydrogenation of cinnamaldehyde at room temperature, respectively, indicating the enhanced catalytic activity by the addition of silica.

The composite photocatalyst with layered nanoarray structure, CdS-sensitized ZnO nanorod arrays (ZnONRA/CdS) grown on ordered TiO2 nanotube arrays (TiO2NTA), was constructed. The performance of composite photocatalyst toward to hydrogen production from water splitting was investigated. The ZnONRA/CdS composite photocatalyst with the substrate layer of ordered TiO2NTA has the enhanced rate of hydrogen production and the improved photostability. It may be attributed to the one-dimensional structure of TiO2NTA at the bottom of ZnONRA/CdS composite photocatalyst, which provides a direct transfer pathway of photoinjected electrons along the photoanode to enhance charge-collection efficiency and consequently reduce electron–hole recombination.

A Pt@TNT catalyst with Pt nanoparticles entrapped in titanate nanotubes (TNT) was prepared by hydrophobic modification of the exterior surface of the TNT and impregnation with hexachloroplatinic acid (H2PtCl6) aqueous solution. The catalyst's enhanced activity towards the hydrogenation of phenol (as high as ∼3200 gphenol h(-1) gPt(-1) of qTOF) can be ascribed to the confinement effect.

CdS nanoparticles were confined within titanate nanotubes (TNTs) by an ion-exchange reaction and a subsequent sulfurization process. Prior to the ion-exchange reaction, the exterior surfaces of the TNTs were modified by a silane coupling agent to make CdS nanoparticles selectively deposit on the inner wall. The composites were characterized by high-resolution transmission electron microscopy, powder x-ray diffraction, inductively coupled plasma atomic emission spectrometry, N2 adsorption–desorption and UV–vis absorption spectra. The results confirm that CdS in the range of 2–3 nm in diameter are confined within the inner cavity of the TNTs. CdS confined within TNTs shows a significant blue-shift of the absorption band edge compared with CdS nanoparticles deposited on the exterior surface of TNTs. Also the TNTs-confined CdS composite exhibits enhanced photocatalytic activity and photostability for hydrogen evolution under visible light illumination due to the quantum size effect of CdS as a result of the spatial confinement effect of the TNTs.

ZnO/CdS/ZnS and ZnO/ZnS/CdS nanorod array photoelectrodes were constructed and fabricated by an alternative chemical bath deposition of CdS and ZnS layers onto the surface of the ZnO nanorod array. The photoelectrochemical performances of composite photoelectrodes were investigated, and the action mechanism of ZnS buffer layers was also considered. The results show that the ZnO/ZnS/CdS nanorod array photoelectrode possesses enhanced hydrogen production efficiency. The enhancement may be attributed to the ZnS buffer layers, which are advantageous in the separation and transportation of photogenerated electron–hole pairs in ZnO/ZnS/CdS nanorod array photoelectrodes.