Photodynamic therapy (PDT) and photothermal therapy (PTT) have been explored widely for application in cancer treatment. In this work, we describe the synthesis of CaTiO3:Yb,Er (CTO) nanofibers co-conjugated with Rose Bengal (RB) and gold nanorods (AuNRs), which offer the potential for combined upconversion photoluminescence (UCPL) and enhanced, synergistic PDT and PTT. Based on this delivery platform, RB and AuNRs served as the PDT and PTT agents, respectively. RB and AuNRs have strong and well-matched absorption with the green and red emissions of UCPL CTO nanofibers respectively, hence a single 980 nm continuous wave laser with deep tissue penetration can be employed to allow PDT and PTT to occur simultaneously. The nanocomposite can effectively convert the near-infrared (NIR) radiation from the laser into a combination of targeted hyperthermia and generation of reactive oxygen species (ROS). In comparison with PDT or PTT alone, the combined PDT/PTT treatment showed significantly enhanced suppression of the viability of Hep G2 cells in vitro, demonstrating its potential for use in oncology.

MicroRNAs (miRNAs) play a key role in regulating gene expression but can be associated with abnormalities linked to carcinogenesis and tumor progression. Hence there is increasing interest in developing methods to detect these non-coding RNA molecules in the human circulation system. Here, a novel FRET miRNA-195 targeting biosensor, based on silica nanofibers incorporated with rare earth-doped calcium fluoride particles (CaF2:Yb,Ho@SiO2) and gold nanoparticles (AuNPs), is reported. The formation of a sandwich structure, as a result of co-hybridization of the target miRNA which is captured by oligonucleotides conjugated at the surface of CaF2:Yb,Ho@SiO2 fibers and AuNPs, brings the nanofibers and AuNPs in close proximity and triggers the FRET effect. The intensity ratio of green to red emission, I541/I650, was found to decrease linearly upon increasing the concentration of the target miRNA and this can be utilized as a standard curve for quantitative determination of miRNA concentration. This assay offers a simple and convenient method for miRNA quantification, with the potential for rapid and early clinical diagnosis of diseases such as breast cancer.

•Proposing a simple hydrothermal route for the preparation of Bi4Ti3O12 nanosheets.•Bi4Ti3O12 nanosheets are dominated with (0 1 0) facets.•Bi4Ti3O12 nanosheets are micrometer-size in lateral and ca. 30 nm in thickness.•Preferential adsorption of (C6H10NO8)3− ions on (0 1 0) leads to Bi4Ti3O12 nanosheets.•Penetration of K+ induces the overlapped Bi4Ti3O12 nanosheets exfoliation.Single-crystalline Auivillium Bi4Ti3O12 nanosheets with dominant (0 1 0) facets have been successfully synthesized by using ammonium bismuth citrate (C6H10BiNO8) as bismuth sources via a conventional hydrothermal route. The as-prepared Bi4Ti3O12 nanosheets were characterized by X-ray diffracton, field-emission scanning electron microscopy, transmission electron microscopy (TEM), high resolution TEM, and selected area electron diffraction. In order to understand the formation mechanism of the Bi4Ti3O12 nanosheets, a set of time-dependent experiments were carried out. The results reveal that the (C6H10NO8)3− ions involved in the feedstock suspensions released by the ionization of C6H10BiNO8 play an important role in the formation of the Bi4Ti3O12 nanosheets. A possible formation mechanism of the Bi4Ti3O12 nanosheets has been discussed based on the analyses of the lattice structure of Bi4Ti3O12 and the effect of C6H10BiNO8 used in the feedstock precursors.

•Coloration processes of amorphous and crystalline WO3 films are studied by SE.•Amorphous WO3 can store more H+ ions compared to crystalline one at same voltage.•The optical parameters of crystalline WO3 are much more sensitive to the H+ ions.•Difference of electrochromic mechanisms between amorphous and crystalline WO3 is proved by SE.Amorphous and crystalline electrochromic WO3 films exhibit quite different optical properties during coloration process. In the present work, amorphous and crystalline electrochromic WO3 films prepared by a solution method were characterized using X-ray diffraction, scanning electron microscope, and transmission electron microscope techniques. A double-layer model with sharp interfaces was established for the fitting of the ellipsometry parameters. The results show that the proton favors amorphous films more than crystalline WO3 films. The refractive indices of both amorphous and polycrystalline WO3 films decrease while extinction coefficients increase with the inserting of H+ during the coloration process. But the optical parameters of the latter are much more sensitive to the H+ ions injected compared to the amorphous WO3 during the coloration process. That is the refractive index modulation of the crystalline WO3 films is about 53% at 633 nm while that of the amorphous films about 15% at the same wavelength. The Drude-like free electron model for crystalline WO3 and hopping mechanism of small polaron for amorphous WO3 are used to explain the difference in detail. These results are very helpful for the better understanding of the coloration process and for the design of electrochromic devices.Download high-res image (104KB)Download full-size image

The investigation of nano-carriers with controllable and trackable drug release kinetics has attracted worldwide attention for new tumor theranostic strategies with catabatic side effects. Herein, a range of monodispersed core–shell structured photoluminescent SrTiO3:Yb3+,Er3+@mSiO2 nanoparticles were designed and synthesized. The surfactant cetyltrimethylammonium bromide (CTAB) was used to vary the microstructure of the mesoporous SiO2 shell. The specific surface area and pore volume increase proportionally with the content of CTAB. Consequently, the doxorubicin (DOX) loading capacity increases, and the drug release kinetics possesses a sustained behaviour. More importantly, the DOX release kinetics was found to correspond well to the evolution of the up-conversion luminescence (UCL) phenomenon. More rapid drug release induces more rapid photoluminescence enhancement, and vice versa. This study has therefore been anticipated to suggest another promising multifunctional drug delivery platform for advanced chemotherapies.

Implantable localized drug delivery systems (LDDSs) have been intensively investigated for cancer therapy. However, the anticancer agent release behavior as well as the local therapeutic process in the complex physiological environment remains a dark zone and consequently hinders their clinical applications. Herein, a series of Er3+-doped electrospun strontium titanate (SrTiO3, STO) nanofibers with refined microstructural characteristics were exploited as a localized carrier for doxorubicin (DOX) delivery due to its light-responsive functionalities as well as expected biocompatibility. The highest DOX loading capacity and sustained releasing kinetics were obtained from the nanofibers with the highest surface area and lowest pore dimensions. Consequently, such nanofibers presented stronger in vitro anticancer efficacy to Hep G2 cells compared to that of other samples. More importantly, the amount of drug released was monitored by the ratio of green-to-red emission (I550/I660) due to the fluorescence resonance energy transfer (FRET) effect built between DOX molecules and upconversion photoluminescent nanofibers. The selective quenching effect of green emission due to DOX molecules was gradually weakened with drug releasing progress, whereas the intensity of red emission barely changed, resulting in an increased I550/I660 ratio. Such color evolution can be feasibly visualized by the naked eye. Monitoring with a spectral intensity ratio eliminates the disturbance of uncertainties in the complex physiological environment compared to just referring to the emission intensity. Such dual-color luminescent STO:Er nanofibers, designed based on the FRET mechanism, are therefore considered to be a promising new LDDS platform with ratiometric-monitored DOX release functionalities for future localized tumor therapeutic strategies.Keywords: doxorubicin; electrospinning; fluorescence resonance energy transfer (FRET); localized drug delivery system; SrTiO3:Er nanofibers

Bone regeneration and scaffold degradation do not usually follow the same rate, representing a daunting challenge in bone repair. Toward this end, we propose to use an external field such as light (in particular, a tissue-penetrating near-infrared light) to precisely monitor the degradation of the mineralized scaffold (demineralization) and the formation of apatite mineral (mineralization). Herein, CaTiO3:Yb3+,Er3+@bioactive glass (CaTiO3:Yb3+,Er3+@BG) nanofibers with upconversion (UC) photoluminescence (PL) were synthesized. Such nanofibers are biocompatible and can emit green and red light under 980 nm excitation. The UC PL intensity is quenched during the bone-like apatite formation on the surface of the nanofibers in simulated body fluid; more mineral formation on the nanofibers induces more rapid optical quenching of the UC PL. Furthermore, the quenched UC PL can recover back to its original magnitude when the apatite on the nanofibers is degraded. Our work suggests that it is possible to optically monitor the apatite mineralization and demineralization on the surface of nanofibers used in bone repair.

3D flower-like PbTiO3 nanostructures self-assembled with (101) nanosheets have been realized by the hydrothermal treatment of the mixture of the lead and titanium hydroxides under the effect of high KOH concentration. The layered K2Ti6O13 formed in situ under the effect of the high KOH concentration plays an important role in the crystallization of the primary PbTiO3 nanosheets and the further self-assembly of the 3D flower-like perovskite PbTiO3 nanostructures. The self-assembled 3D flower-like perovskite PbTiO3 nanostructures express good mesoporous structures and high specific surface area. In consequence, the 3D flower-like perovskite PbTiO3 nanostructures as supports show excellent ability to enhance the catalytic activity of Pt. Over the Pt/PbTiO3 nanoflowers, the CO instantaneously completely converts to CO2 at a very low temperature of ca. 107 °C facilitating the catalytic purification of the automotive exhaust produced in the cold-start period.

Ferroelectric oxides with excellent electrical, mechanical and optical multifunctions play a vital role in future microdevices with diverse applications in energy, sensors and actuators. A series of Er doped PbZr0.52Ti0.48O3 (PZT:Er3+) nanofibers with tunable upconversion photoluminescence (PL) properties were successfully synthesized via a sol–gel based electrospinning process. By controlled crystallization, PZT:Er3+ nanofibers evolve from a polycrystalline to a single-crystalline-like structure, resulting in a remarkable increase in the visible upconversion emission intensity. It was uncovered that Er3+ doping site in PZT shifts from B site to A site with increase in crystallinity and crystal size. In addition, remarkable enhancement in red emission is observed with increased Er3+ doping concentration, which facilitates the modulation of emission colour from green to orange. Combined with the excellent ferroelectric properties of PZT, such spectral tunable PZT:Er3+ nanofibers are considered as a promising multifunctional candidate for integrated electro-mechano-optical devices.

750–850 nm (NIR I) and 1000–1400 nm (NIR II) in the near infrared (NIR) spectra are two windows of optical transparency for biological tissues with the latter capable of penetrating tissue deeper. Monitoring drug release from the drug carrier is still a daunting challenge in the field of nanomedicine. To overcome such a challenge, we propose to use porous Nd3+-doped CaTiO3 nanofibers, which can be excited by NIR I to emit NIR II light, to carry drugs to test the concept of monitoring drug release from the nanofibers by detecting the NIR II emission intensity. Towards this end, we first used electrospinning to prepare porous Nd3+-doped CaTiO3 nanofibers by adding micelle-forming surfactant Pluronic F127, followed by annealing to remove the organic component. After a model drug, ibuprofen, was loaded into the porous nanofibers, the drug release from the nanofibers into the phosphate buffered saline (PBS) solution was monitored by detecting the NIR II emission from the nanofibers. We found that the release of the drug molecules from the nanofibers into the PBS solution triggers the quenching of NIR II emission by the hydroxyl groups in the surrounding media. Consequently, more drug release corresponded to more reduction in the intensity of the NIR II emission, allowing us to monitor the drug release by simply detecting the intensity of NIR II from the nanofibers. In addition, we demonstrated that tuning the amount of micelle-forming surfactant Pluronic F127 enabled us to tune the porosity of the nanofibers and thus the drug release kinetics. This study suggests that Nd3+ doped CaTiO3 nanostructures can serve as a promising drug delivery platform with the potential to monitor drug release kinetics by detecting the tissue-penetrating NIR emission.

The design of multifunctional localized drug delivery systems (LDDSs) has been endeavored in the past decades worldwide. The matrix material of LDDSs is known as a crucial factor for the success of its transformation from the laboratory to clinical practices. Herein, a biocompatible ceramic, strontium titanate (SrTiO3, STO), was utilized as the matrix. A variety of fine Er doped SrTiO3 (STO:Er) nanofibers were fabricated via electrospinning. After the surface functionalization with amino groups, the drug loading capacity of STO:Er nanofibers is dramatically increased. The nanofibers present a rather sustained drug releasing behavior in the media with pH of 7.4, and the release kinetics is significantly accelerated with the decreased pH value from 7.4 to 4.7. Furthermore, the intensity of the spectrum emitted from the STO:Er nanofibers corresponds well with the drug releasing progress under the excitation of near-infrared spectrum (∼980 nm). Fast drug release behavior (in an acid environment) induces a rapid intensity enhancing effect of photoluminescence emission and vice versa. The main mechanism is attributed to the quenching effect induced by the C-Hx groups of IBU molecules with vibration frequencies from 2850 to 3000 cm–1. Such new STO:Er nanofibers with pH-triggered and optically monitored drug delivery functionalities have therefore been considered as another new localized drug delivery platform for modern tumor diagnosis and therapy.Keywords: drug delivery; electrospinning; optical monitoring; pH-triggered; SrTiO3:Er nanofibers

Single-crystal TiO2/PbTiO3 nanofiber composites were prepared by a simple hydrothermal synthesis and annealing treatment at 650 °C, where pre-perovskite (PP) PbTiO3 (PTO) and tetrabutyl titanate (TBOT) were used as precursors. In the composites, anatase TiO2 nanorods grew on the surface of tetragonal perovskite (TP) PTO nanofibers and formed sharp TiO2/PbTiO3 interfaces, leading to single-crystal heterostructures. The as-synthesized heterostructured nanofiber composites exhibited excellent photocatalytic activity for degradation of methylene blue (MB) under visible light irradiation (λ > 400 nm). Especially, the composites TiO2/PbTiO3 TBOT: 0.4 mL showed the highest photocatalytic activity, and the degradation rate of MB was 0.02392 min−1. Such photocatalytic activity of the heterostructured nanofiber composites was supposedly attributed to the large-scale formation of the sharp interfaces, which could be critical for the photogenerated charge carrier separation and its transfer from the PTO phase to TiO2. It is suggested that the obtained heterostructured nanofiber composites TiO2/PbTiO3 can be exploited as an alternative visible-light-driven photocatalyst.

Single-crystal heterostructured PbTiO3/CdS nanorods were fabricated by a hydrothermal process. In the composites, well-crystalline CdS nanoparticles grew on the surfaces of tetragonal perovskite PbTiO3 nanorods and formed sharp PbTiO3/CdS interfaces. It was revealed that the as-synthesized heterostructured PbTiO3/CdS nanorods exhibited higher photocatalytic performance in the degradation of MB under visible light irradiation than pristine PbTiO3 nanorods and CdS nanoparticles. The enhanced performance is associated with a suitable band alignment and the promoted separation of photogenerated carriers by forming sharp interfaces between PbTiO3 and CdS in the heterostructure. Our results suggest that the heterostructured PbTiO3/CdS nanorods may be promising for highly efficient visible-light-driven photocatalysts.

•Porous hollow CaTiO3 nanofibers were synthesized via electrospinning.•The electrospinning process expedites phase separation leading to the formation of core–shell nanofibers.•Tuning of the hollow core and fiber dimension were achieved by altering the PVP/CTO molar ratio.The synthesis of porous CaTiO3 (CTO) nanotubes with controlled microstructure was demonstrated via a single-nozzle electrospinning approach. Homogenous sols comprising polyvinylpyrolidine (PVP), Pluronic F127 and CTO (metal salt) were electrospun, which resulted in fine CTO nanotubes due to phase separation phenomenon. PVP/CTO molar ratio was confirmed to induce the effective manipulation of its structural characteristics. Altering the ratio from 0.24 m to 0.12 m was found to result in the increased fiber diameter, from ~105 nm to ~230 nm, and the enhanced hollow structure (diameter of ~70 nm). Further development of biocompatible inorganic CaTiO3 nanotubes with such tunable hollow structures provides a platform for sustained drug loading and delivery.

Understanding the energy transition which is influenced by doping ions and host materials in the upconversion (UC) physical processes is of vital importance for further optimizing performance and extending applications of UC materials. In this work, we have selected 4% Er-doped perovskite PbTiO3 (PTO) nanofibers as a model system to explore the effects of tetragonality and polarization on UC photoluminescence (PL) properties. By means of in situ X-ray diffraction, the tetragonality and polarization of these nanofibers have been determined to gradually decrease with an increasing of the temperature from 50 to 300 K, leading to obvious enhancements in UC green band emission of 523 nm (about 43 times) and red band emission of 656 nm (about 8 times), in contrast to the decreased green and red UC intensities in Er-doped BaTiO3 or PTO particles. Moreover, the significant enhancement in the intensity ratio of green to red bands from 0.17 to 0.86 has been achieved, indicating that the emission enhancement is highly wavelength-dependent. On the basis of in situ UC decay curves from 50 to 300 K, the UC lifetimes of the 4S3/2 and 4F9/2 level have been derived to be 128.04 ± 0.47 μs and 278.10 ± 1.07 μs at 50 K, respectively, and the values are basically maintained as the temperature increases. The observed UC phenomena in Er-doped perovskite PTO nanofibers can be ascribed to an assisted effect of the low-energy E(1TO) phonon on the UC process. Such phonon energy can be easily tailored by the tetragonality and polarization; thus, a modification of UC emissions in Er-doped PTO nanofibers has been achieved. The findings in this work could provide new insights into understanding the UC process in perovskite oxides and offer an opportunity to tune UC emission by an external field, such as an electric field, in addition to temperature.

Perovskite PbTiO3 (PTO) nanocrystals with a truncated octahedral morphology have been prepared by a facile solid-state reaction. Pt nanoparticles preferentially nucleated on the {111} facet of PTO nanocrystals exhibit a remarkable low-temperature catalytic activity towards CO oxidation from a temperature as low as 30 °C and achieve 100% conversion at ∼50 °C.

Octahedral-shaped perovskite PbTiO3 nanocrystals (PT OCT) with well-defined {111} facets exposed have been successfully synthesized via a facile hydrothermal method by using LiNO3 as an ion surfactant. The Li–O bond on the surface of PT OCT nanocrystals is essential to the stability of such nanocrystals and also results in a dramatic high visible-light photocatalytic activity.

A brushlike PbTiO3 (PTO)/ZnO nanocomposite with ZnO nanowires (NWs) grown epitaxially on the surface of single-crystal ferroelectric tetragonal PTO NWs is successfully fabricated onto a flexible substrate via a two-step hydrothermal process. In this nanocomposite, a ZnO NW grew along [0001] on the (101) plane of the core PTO NW with a lattice mismatch of 1.06% to form an effective ferroelectric/semiconductor interface. It is found that the ultraviolet photoluminescence emission of the nanocomposite could be easily tuned by its bending curvatures at room temperature. This intriguing phenomenon can be understood by the bending-induced polarization field from the PTO NW, which could reduce the bending degree of the energy band of the ZnO NWs through the interface. Throughthe design of an effective interface, this kind of ferroelectric/semiconductor nanocomposite may find potential applications in sensor and piezophotonic nanodevices.Keywords: flexible nanocomposites; lead titanate; photoluminescence; zinc oxide

•Monodispersed LiFePO4 nanopillows were solvothermally synthesized with ethylene glycol.•LiFePO4@C core–shell nanostructures were prepared by a facile method in high yield.•LiFePO4@C core–shell nanostructures show nice capacity retention and high rate capacity.•A facile method was proposed simply to prepared fully carbon-coated LiFePO4 cathode.In this paper, monodispersed LiFePO4 nanopillows have been successfully synthesized via solvothermal route with ethylene glycol (EG) as reaction medium. Subsequently, with the basis of the solvothermally synthesized monodispersed LiFePO4 nanopillows, monodispersed LiFePO4@C core–shell nanostructures are facilely prepared in high yield. Based on the experimental results, the formation mechanism of the monodispersed LiFePO4 nanopillows has been discussed simply. The monodispersed LiFePO4@C core–shell nanostructures exhibit nice capacity retention and high rate capacity due to the full carbon-coating and the well-crystallized nanosized particles.Monodispersed LiFePO4 nanopillows are solvothermally synthesized with ethylene glycol as solvent and subsequently bring about monodispersed LiFePO4@C core–shell nanostructures exhibiting high discharge capacity of 112 mAh g−1 at 30 C.

A novel approach that combines a modified sol–gel process with a PVA-assisted hydrothermal reaction at 200 °C for 12 h has been developed to prepare single-crystal pre-perovskite PbTiO3 nanofibers with good dispersity and length control. By increasing the dosage of triethanolamine (TEA) solution into the Ti precursor to modify the sol–gel process, the length of the nanofibers in the prepared samples decreased from about 35–90 μm to 5–12 μm, whereas the corresponding diameter remained in the range of 100–300 nm. Further, the dispersity of the samples, as well as the diameter uniformity of a single nanofiber, was improved significantly. In particular, a broad green photoluminescence (PL) emission (~550 nm) was observed in the nanofibers at room temperature. It is interesting to find that no obvious size effect was detected on the green PL emission.

Mesoporous structure-tailored SrTiO3 mesoporous spheres have been hydrothermally realized by controlling the silicate semipermeable membranes with KOH concentration. The phase and microstructures were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, thermogravimetric analysis and N2-physisorption techniques, respectively. Because the high KOH concentration lowers the polymerization degree of the silicate anion species, the silicate semipermeable membranes become thinner with increasing KOH concentration. Whereas the attenuated silicate semipermeable membranes favour the penetration of the metal ions, the primary SrTiO3 nanocrystallites for the self-assembly of the SrTiO3 mesoporous spheres grow larger as the KOH concentration increases. As a consequence, the mesoporous structures of the self-assembled SrTiO3 mesoporous spheres can be simply tailored by adjusting the KOH concentration of the hydrothermal reaction system. Moreover, because the attenuation of the silicate membrane facilitates the orientation attachment of the primary nanocrystallites, the self-assembled SrTiO3 mesoporous spheres trend to single-crystal-like with the increasing KOH concentration.

In this work, ferroelectric/antiferroelectric heterostructured PbTiO3/PbZrO3 composite fibers were fabricated via hydrothermal method. Single-crystal perovskite tetragonal PbTiO3 (PT) nanofibers were employed as the growing core to react with PbZrO3 (PZ) precursors under hydrothermal conditions. Structural characterization indicated that the composite fiber consisted of single-crystal PT and PZ phases. Moreover, an epitaxial growth between the PT nanofiber and PZ crystal was revealed to occur at (01)PT/(221)PZ. At the interface, Zr4+ ions were determined to diffuse into the nanofiber within ~20 nm and possibly partially substituted Ti4+ positions in the perovskite PT. Based on all these findings, it is proposed that single-crystal PZ crystals were possibly formed on the nanofibers via diffusion and then epitaxial growth under hydrothermal condition. These PT/PZ composite fibers may offer an opportunity to explore fascinating properties including dielectricity and ferroelectricity at the ferroelectric/antiferroelectric interface.

A facile hydrothermal method has been developed to prepare single-crystal BiFeO3 (BFO) microplates, where the raw material (C6H10BiNO8) was used both as a reactant and a surface modifier. The as-synthesised BFO microplates were dominated by (012) facets with the lateral length of 8 μm and thickness of 510–550 μm. The results of XRD, SEM, TEM, HRTEM and FT-IR indicate that the adsorption behaviour of the organic ligands could play a key role in the formation of the BFO microplates. Moreover, the dielectric constant of the BFO–PVDF film is much higher than the pure BFO at room temperature. The specially chosen raw material (C6H10BiNO8) and the proposed formation mechanism of the BFO microplates could be extended to tailor the crystal growth of the 2D structures of other perovskite oxides.

This study reports the improvement in the mechanical properties of SnO2:F (FTO) thin films through the modification of the structure and surface morphology. The FTO thin films are deposited on glass substrates by the atmospheric pressure chemical vapor deposition method on an industrial production line. Both the average grain size and the surface roughness were progressively increased by increasing the flow rate of metal organic monobutyltin trichloride (MBTC). The hardness and Young's modulus of the FTO films increased from 9.01 GPa to 15.08 GPa, and from 125.24 GPa to 206.93 GPa, respectively, according to the nanoindenter results. Post-heat treatment at 650 °C for 10 min resulted in a further increase in the hardness and Young's modulus, reaching maximum values of ~15.89 GPa and ~235.9 GPa, respectively. The enhancement in mechanical properties can be attributed to the reduced grain boundaries and the improved structural densification.

•The FTO films with SiCxOy or SixSnyO2 barrier layer are deposited on industrial line.•Preferred orientation along (2 0 0) plane was enhanced via inserting barrier layer.•SnO2:F/SiCxOy films showed improved electrical properties.•SiCxOy film was a great barrier layer candidate during FTO thin film production.Polycrystalline fluorine-doped SnO2 thin films with SiCxOy or SixSnyO2 barrier layer are deposited on glass substrates by atmospheric pressure chemical vapor deposition (APCVD) method. The effect of barrier layer on structure and electrical property of FTO films was investigated. Results show that the inserting of barrier layer, especially the SiCxOy layer, has led to the improved crystallinity and the enhanced preferential orientation along the (2 0 0) crystallographic plane. SnO2:F/SiCxOy/Glass films with larger grain size and a columnar growth structure exhibited lower resistivity (~4.9×10−4), higher reflectance in the mid-far-infrared region (~80%) and lower emissivity (0.16), while maintaining high transmittance in the visible range. The SiCxOy film has therefore been considered as a more ideal potential barrier layer for FTO thin film production.

•Various fluorine-containing Y-SiAlON glass-ceramics were prepared by carbothermal reduction.•XRD and SEM reveal the presence of different crystal phases.•Addition of fluorine promoted the α-Si3N4 to Y2Si3O3N4 and β-Si3N4 phase transformation.•By controlling nucleation, enhancement of mechanical properties can be achieved.Various fluorine-containing Y-SiAlON glass-ceramics from a mixture of Y2O3, α-Si3N4, SiO2, and Al2O3 using AlF3 as the fluorine source were prepared by one-step or two-step carbothermal reduction process. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to study the crystallization behavior of the glass-ceramics. The compositions of the crystals and the glass phase were semi-quantitatively determined by EDX. The final glass-ceramics contained N-containing melilite (Y2Si3O3N4) and β-Si3N4 together with a secondary phase of yttrium aluminum garnet (YAG, Y3Al5O12). The investigated Y-SiAlON glass-ceramics with higher F content showed better sintering properties. Fluorine has important effects on crystallization of glass-ceramics as it affects the crystallization mechanism by reducing the thermal energy barrier for crystallization. By controlling the reaction, the Y-SiAlON glass-ceramics are first held at 1300 °C for 4 h, which contrasts with the samples obtained after direct sintering at 1550 °C, the conversion to Y2Si3O3N4 and β-Si3N4 is promoted and the final microstructure consists of elongated β-Si3N4 grains. These glass-ceramics showed relatively better mechanical properties.

The Er-doped preperovskite and perovskite single-crystal PbTiO3 (PTO) nanofibers with a series of doping concentration (0–4 mol %) were successfully synthesized by hydrothermal method and solid state phase transformation method, respectively. The XRD, XPS, and Raman results indicated that Er3+ occupied Pb2+ site in preperovskite PTO and Ti4+ site in perovskite PTO nanofibers. The photoluminescence (PL) measurements indicated that only the strong green emission corresponding to the preperovskite PTO host matrix was observed, whereas up-conversion (UC) emission under infrared excitation (980 nm) was absent. In contrast, the strong green emission (at 524 and 554 nm) and the weak red emission around 670 nm of Er3+ occurred in the PL and UC PL processes of Er-doped perovskite PTO nanofibers. The distinguished difference in these two kinds of nanofibers might be attributed to the substitution sites and chemical environments of Er3+. It is suggested that such Er-doped single-crystal perovskite PTO nanofibers could be interesting objects for applications in mechanical–electrical luminescence such as electric field modulation luminescence and mechanoluminescence.

A facile hydrothermal method has been developed to synthesize single-crystal ferroelectric PT nanoplates by using K2Ti6O13 nanowires as synthetic precursor. The PT nanoplates with dominant {001} facets have the side length of 500–700 nm and height of 100–150 nm. Piezoelectric force microscopy (PFM) results demonstrated that the PT nanoplates show obvious piezoelectric and ferroelectric activity. Moreover, the crystal growth of the PT nanoplates has been discussed. The results revealed that the gradual dissolution of K2Ti6O13 nanowires in alkali solution and the template of lead oxide are essential to the formation of PT nanoplates.

Single-crystal strontium titanate (SrTiO3) nanosheets have been synthesized via a solvothermal reaction route with ethylene glycol (EG) as reaction medium solvent. The as-synthesized SrTiO3 products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and high resolution transmission electron microscopy, respectively. The results show that the single-crystal SrTiO3 nanosheets are parallel to the (110) plane and self-assembled by primary nanocrystallites in monolayer. EG as a organic solvent plays an important role in the synthesis of the single-crystal SrTiO3 nanosheets. Based on the experimental results, a possible formation mechanism of the single-crystal SrTiO3 nanosheets has been proposed.

•The large-scale, textured SnO2:F film was prepared by APCVD on an industrial line.•The textured surface morphology and haze value were optimized significantly.•The film showed excellent light trapping structure for solar cell applications.In order to optimize the light trapping, textured SnO2:F (FTO) films have been successfully deposited and optimized on glass in large scale using atmospheric pressure chemical vapor deposition (APCVD) method on an industrial production line. The microstructures, optical and electrical properties of the films were investigated as a function of the total flow rate and fluorine doping concentration. The as-deposited FTO polycrystalline films possessed the tetragonal rutile structure of SnO2. Enhanced light trapping has been achieved with the increased surface roughness of the films by manipulating the total flow rate of monobutyltin trichloride (MBTC) and trifluoro acetic acid (TFA), while the corresponding high transmittance and conductivity remained stable. The optimized film with haze value of 10.9%, a figure of merit at the level of ∼10−3 and sheet resistance of ∼11 Ω sq−1, showed good potential to improve the efficiency of silicon thin film solar cells.

Perovskite-related oxides exhibiting fascinating electric and magnetic properties are important functional materials. We report, for the first time, that pre-perovskite (PP) PbTiO3, characterized by one-dimensional (1D) TiO6 octahedron columns, has a direct-band structure with a gap of 3.20 eV. The faceted single-crystal nanofibers of PP-PbTiO3 demonstrate strong green and near infrared (NIR) photoluminescence (PL) emission at room temperature, which are intrinsic and subjected to quasi-1D crystal structure and electronic band structure. These nanofibers serving as new direct band-gap semiconductors may find applications in novel optical and optoelectronic devices.

Nanocrystalline silicon (nc-Si) films were synthesized via different re-crystallization approaches from amorphous silicon (α-Si:H) films deposited using plasma enhanced chemical vapor deposition (PECVD). The microstructure evolution with various annealing conditions was investigated via high resolution transmission electron microscopy (HRTEM) and Raman spectrometry. It was found that, compared with the conventional solid phase crystallization (SPC) annealing, a rapid thermal process (RTP) pre-annealing at 600 °C for 60 s can significantly enhance the recrystallization process and the electrical conductivity of nc-Si films. In addition, for the nc-Si films with similar crystal sizes, it was uncovered that the logarithm of conductivity presented a linear relationship with the crystalline volume fraction. This study has therefore been an important step forward to the future synthesis of the nc-Si films with manipulated microstructure and electrical conductivity for further applications.Highlights► The nc-Si films with controlled microstructure and electrical conductivity (σ) ► The crystal size was controlled at ~ 5 nm at the controlled process condition. ► Logarithm of σ is linearly proportional to the crystallized fraction under the circumstance above. ► RTP enhanced the recrystallization and conductivity of the Si films.

•The sandwich structural low-e glass was prepared on an industrial line.•The film showed stable morphology and functional property under low temperature.•The functional property decreased dramatically after long time tempering at 650 °C.The low-emission glass was prepared via depositing fluorine-doped tin oxide thin film on glass substrate by atmospheric pressure chemical vapor deposition method. The as-deposited low-emission glass was found to present a SnO2:F/SiCxOy/glass sandwich structure via focused ion beam technique and transmission microscopic measurement. After tempering process at ~ 650 °C with varied periods, the electrical and optical properties of the SnO2:F thin film remained stable for less than 10 min, but decreased dramatically when the tempering period exceeded 10 min, which was mainly due to the oxygen chemisorptions and fluorine ion diffusion. It was observed that the SnO2:F thin films presented uniform polycrystalline nature of cassiterite structure throughout the tempering process. The study has therefore suggested the appropriate tempering conditions for the SnO2:F low-emission glass, and provided a critical guidance for further energy-saving glass applications.

In this work, single-crystalline α-FeOOH nanorods with a length of 400–700 nm and a diameter of 20–80 nm were successfully synthesized via a facile template-free hydrothermal method. Single-crystalline mesoporous α-Fe2O3 and Fe3O4 nanorods could be obtained from these α-FeOOH precursors after calcining at 350 °C in air and 500 °C in nitrogen, respectively. The as-prepared single-crystalline mesoporous α-Fe2O3 and Fe3O4 nanorods exhibited a large specific surface area and porosity, effectively enhancing the electrochemical reaction area and accommodate the strain during the charge–discharge cycling process.

Shape-controlled synthesis of tetragonal PbZr0.52Ti0.48O3 (PZT) perovskite nanocrystallites, microrolls, microrods and 3D complex architectures composed of microroll-bundles or microrod-bundles were realized via a hydrothermal reaction route by simply adjusting the poly-vinylalcohol (PVA) and KOH concentrations. X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), differential temperature and thermogravimetric analysis (DTA and TG) were used to characterize the phase composition, morphology and thermal behaviors of the synthesized samples. In order to investigate the effect of PVA on the shape-controlled synthesis of the tetragonal PZT perovskite particles, a series of experiments were performed by changing the PVA and KOH concentration. Based on the experimental results, the formation mechanisms of tetragonal PZT perovskite particles with various shapes and the effects of the PVA macromolecular conformation are discussed.

Ba-doped (0–8 mol%) pre-perovskite PbTiO3 single-crystal fibers have been synthesized in large-scale reproducibly by a facile polymer-assisted hydrothermal method. X-ray power diffraction, scanning electron microscope and transmission electron microscope were performed to investigate microstructure and the evolution of these single-crystal fibers. The results show that these fibers have a length of 13–120 μm and a diameter of 100–600 nm. In particular, these Ba-doped pre-perovskite PbTiO3 fibers can transform to tetragonal perovskite Ba-doped PbTiO3 (PBT) fibers with single-crystal character. Piezoresponse force microscopy measurements indicate that the perovskite PBT with Ba concentration of 5 mol% has a symmetric “square” phase loop, and the amplitude loop shows a “butterfly shape”, confirming the existence of ferroelectric and piezoelectric properties. Such findings have thus provided a promising route for the nanoscale sensors and generators applications.

A series of amorphous carbon-based films were deposited on the nanostructured Ag layers to observe surface plasmon (SP) enhanced photoluminescence (PL). The dependence of PL peak wavelength and intensity on the film composition and the nanostructure of the Ag layers were systematically investigated. The PL wavelength was tuned from 442 nm to 635 nm by varying the carbon content of the as-deposited carbon-based films. The nanostructure of Ag layers varied from nanoparticles (NPs) to continuous films via process control. With the SPs generated at the carbon-based film/Ag layer interface, the PL intensity was found to be significantly enhanced with a peak enhancement factor of 6, and the light emission range of the composite films was extended to 434–653 nm. The dependence of PL intensity on the spectral overlap between the carbon-based films and plasmon resonant Ag layers, Ag surface morphology and the internal quantum efficiency (IQE) of the carbon-based films was discussed. The redshift of SP resonance with the increasing refractive index of the upper carbon-based films was observed.Highlights► The light emission of amorphous carbon-based films is enhanced by surface plasmons. ► The light emission range is extended by surface plasmons. ► SP resonance redshifts with increasing refractive indices of the luminescent films. ► SPs are promising to enhance the full-color light emission of carbon-based films.

A range of mesoporous silica nanoparticles (MSNs) with controlled microstructural characteristics were successfully prepared via the binary surfactant templated synthesis approach with varied concentration of triblock copolymer Pluronic F127. The relationship between the MSNs structural evolution and the surfactant concentration was extensively discussed. Ibuprofen (IBU) was loaded as drug model to uncover the in vitro drug releasing kinetics. It was found that the quantity of the drug loaded mainly depended on the specific surface area, while the drug releasing rate was dominantly determined by the length and curvature of the mesopores. This study has uncovered the core influential factors of MSNs system on its drug releasing properties, and thus demonstrated a facile approach to prepare MSNs with manipulated structural characteristics for drug delivery applications.Graphical abstractHighlights► The as-prepared MSNs with manipulated morphology and structural characteristics by varying F127 concentration. ► The pore length and curvature was changed with the shape of MSNs. ► The drug-loading amount was determined by specific surface areas. ► The length and curvature of the mesopores impact on the drug releasing characteristics.

Single-crystal nanofibers of a new structured PbTiO3 with Zr doping concentration of 0–15% have been reproducibly synthesized on a large scale by a polymer-assisted hydrothermal method for the first time. Moreover, the Zr-doped new structured PbTiO3 nanofibers can transform into single-crystalline perovskite Pb(Zr, Ti)O3(PZT) nanofibers by annealing treatment in air.

A new tetragonal phase of PbTiO3 was discovered, in which each TiO6 octahedron pair shares an edge and stacks over following pairs in an interlaced manner to form a one-dimensional (1D) columned structure along the c-axis. This new tetragonal phase of PbTiO3 transforms into a normal perovskite phase in air at elevated temperature.

In this paper, we report a simple hydrothermal method without any surfactants, for the first time, to synthesize single-crystal BaTiO3 dendrites. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED), and high-resolution transmission electron microscopy (HRTEM). The KOH concentration was found to be vital to the final formation of BaTiO3 dendrites. An obvious morphology evolution from sphere-like shape to dendrite was observed when KOH concentration was decreased from 1 M to 0.1 M. It is rational to expect that dendritic structures of other perovskite oxides may also be synthesized by this simple method.

This paper presents the optical absorption and luminescence properties of Er3+ doped mixed alkali borosilicate glasses: 59.5SiO2 · 20B2O3 · xLi2O · (20 − x)Na2O · 0.5Er2O3 and 59.5SiO2 · 20B2O3 · xLi2O · (20 − x)K2O · 0.5Er2O3, with x = 0, 4, 8, 12, 16 and 20 mol%. The variations of Judd–Ofelt intensity parameters (Ω2, Ω4, and Ω6), hypersensitive transition intensities, total radiative transition probability (AT), radiative lifetimes (τR), integrated absorption cross-sections (Σ) and stimulated emission cross-sections (σp) as a function of x are discussed in detail. The changes in Ω2 and intensities of hypersensitive transitions are attributed to optical basicity changes in the host glass matrix, which leads to variations in the covalency of the Er–O bond. The luminescence properties are reported for certain transitions, and the emission cross-section is high at x = 8–12 in the case of lithium sodium glass, whereas in lithium potassium glass it is high at x = 8.

The BiCoxFe1 − xO3 samples have been successfully synthesized by hydrothermal process. The resulting products were characterized by X-ray powder diffraction (XRD), energy dispersive X-ray (EDS), differential thermal analysis (DTA), and physical property measurement system (PPMS).It was found that the magnetization of the obtained products was greatly enhanced by Co substituting for Fe ions. Furthermore, the value of magnetism of BiCoxFe1 − xO3 samples can be adjusted by Fe doping concentration. DTA curve indicates the ferroelectric properties of the obtained BCFO samples are not affected by Co substitution. Therefore, it would be interesting to realize thin films with similar compositions and study their properties in the interest of device applications.

Large-scale α-FeOOH nanowires with uniform diameter and high aspect ratios were synthesized via hydrothermal reaction at 100 °C. The obtained α-FeOOH nanowire was of diameter of 80 nm and length up to 1.2 μm. X-ray diffraction (XRD) results show that the nanowires are of orthorhombic structure, and Fourier transform infrared (FT-IR) analysis further confirms the formation of orthorhombic phase α-FeOOH. High-resolution TEM (HRTEM) studies indicate the single-crystalline nature of α-FeOOH nanowires with an oriented growth along the [001] axis direction. Based on the results of contrastive experiments, the possible mechanism for hydrothermal synthesis of α-FeOOH nanowires was also discussed.

The size-controlled synthesis of barium titanate (BaTiO3) nanocrystals has been achieved by a hydrothermal route with Fe doping and ethylenediamine (en) addition. The as-synthesized BaTiO3 nanocrystals were characterized with XRD, SEM, TEM, and HRTEM. The results revealed that the average particle sizes of Fe-doped samples were reduced compared to that of the sample without Fe doping, suggesting that the doping ions inhibited the crystal growth. It was also found that the average particle size decreased as the Fe doping concentration increased. Furthermore, the addition of en, which served as both solvent and capping agent, could suppress the particle growth and lead to the change in particle shape from sphere to cube by a confined effect.

Tm3+ and Dy3+ ions co-doped aluminoborosilicate glasses were prepared in this study. The luminescence properties of the glasses were analyzed. A combination of blue, green, yellow, and red emission bands was shown for these glasses, and white light emission could be observed under UV light excitation. White light luminescence color could be changed by varying the excitation wavelength. Concentration quenching effect was investigated in this paper. Furthermore, the dependence of luminescence properties on glass compositions was studied. Results showed that the luminescence intensity changed with different network modifier oxides, while the white color luminescence was not affected significantly.Tm3+ and Dy3+ ions co-doped aluminoborosilicate glasses, which emit white light under UV light excitation, were prepared. The dependence of luminescence properties on glass compositions was studied, and results showed that the white color luminescence was not affected significantly with different network modifier oxides. This adjustability could broaden application areas.

The effects of mixed alkaline earth oxides on crystallization and structural changes in a multi-component borosilicate glass system are studied by using X-ray diffraction (XRD) and transmission electron microscope (TEM). It is found that the crystallization is decreased with increasing alkaline earth oxide content and there are also a series changes occurred in TEM images. This paper introduces the conception that alkaline earth ions tend to occupy their preferred sites regardless of glass systems. This conception is assisted to explain the TEM images to some extent by suggesting a simple structural model about non-bridging oxygen in glass network. The conception also indicates a ‘blocking effect’ existing in such a multi-component borosilicate glass system, which may be responsible for XRD results in chief. In addition, the structural model suggested by TEM results refers a new unit of Si–O–M2+–O–B, which helps in understanding the minimum exhibits in XRD results. Moreover, a dielectric test is taken to study glass properties in detail.

The luminescence properties of europium and dysprosium ions co-doped zinc–aluminoborosilicate glasses were analyzed. A combination of blue, green, yellow and red emission bands was shown for these glasses, and white light emission could be observed under UV light excitation. The color of luminescence could be adjusted by varying the proportions of europium and dysprosium. The concentration quenching effect was also investigated in this paper. Furthermore, the reduction of Eu3+ → Eu2+ in air at high temperature was observed in the zinc–aluminoborosilicate glasses.

Nanocrystalline Si-rich silicon oxide films were deposited using plasma enhanced chemical vapor deposition technique with the mixture of silane (SiH4), nitrous oxide (N2O) and hydrogen (H2) as gas source on quartz glass substrate at the substrate temperature of 300 °C. The effect of the ratio N2O/SiH4 on the oxidation, microstructures and photoluminescence (PL) of the as-deposited Si-rich silicon oxide films was investigated with FTIR, XRD and HRTEM. The results reveal that with the increasing ratio of N2O/SiH4, more amounts of oxygen are incorporated in the as-deposited films and more nanosized silicon particles are embedded in the films, forming nanocrystalline Si-rich silicon oxide films. The quantum confinement effect or the cooperation of quantum confinement and luminescence center results in the nanocrystalline Si-rich silicon oxide films of higher PL intensity.

In order to obtain a more accurate dispersion relation for the optical properties of amorphous Si (a-Si) films, a modification on Forouhi–Bloomer's model (FB model) considering the effects of the non-parabolic bands and phonons was performed. A series of experimentally measured optical constant data have been fitted by the modified and original FB models for asserting the advantages of the former. The results indicates that considering the non-parabolic conduction and valence bands for modeling the optical properties of the a-Si films improves the goodness of fits and the modified model provides more useful and correct information about the optical properties.

Nanosized PbZr0.52Ti0.48O3 (PZT) powders are synthesized by a two-stage precipitation route assisted with the polyvinyl alcohol (PVA) evaporation. DTA/TG and XRD were employed to investigate the thermal behavior and phase evaluation of the PZT precursor with PVA polymer. The particle size of the powder calcined at different temperature was observed and characterized by FESEM. The results show that the process provides a technically simple route for the preparation of nanosized, narrow particle distribution and free dense agglomerate PZT powder at low calcination temperature.

Large-scale CdS nanowires with uniform diameter and high aspect ratios were synthesized using a simple solvothermal route that employed CdCl2 and S powder as starting materials, ethylenediamine (en) as the solvent. X-ray diffraction (XRD) pattern and transmission electron microscopy (TEM) images show that the products are hexagonal structure CdS nanowires with diameter of 40 nm and length up to 10 μm. Selected area electron diffraction (SAED) and high resolution TEM (HRTEM) studies indicate the single-crystalline nature of CdS nanowires with an oriented growth along the c-axis direction. The optical properties of the products were characterized by optical absorption spectra and photoluminescence spectra. Based on the results of contrastive experiments, it is found that the sulfur source and the solvent play significant roles in the formation of uniform nanowires. A possible formation mechanism of nanowires is discussed.TEM image of CdS nanowires synthesized using CdCl2 and S as the reactants and ethylenediamine as the solvent under solvothermal conditions.

A wide range of cadmium sulphide (CdS) 1-D nanocrystals were prepared using a novel polyvinylpyrrolidone (PVP)-assisted solvothermal method that employed ethylenediamine (en) as the solvent. X-ray diffraction (XRD) results shows that the nanorods are of hexagonal structure, and are further identified as single crystalline in selected area electron diffraction (SAED). The optical properties of CdS were characterized by optical absorption spectra and photoluminescence spectra. A series of experiments were carried out with different concentrations of PVP, and all the results confirm that the dosage of PVP is a vital factor in the morphology and optical properties of CdS. Moreover when the best dosage of 0.8 g/50 mL was used, continuous single-crystalline nanorods with regular and smooth morphology were obtained. The mechanism for the PVP-assisted solvothermal synthesis of CdS 1-D nanostructures was also investigated, and the reaction model of CdS/PVP was first presented.

Alumina coating, approximately 30 μm, was deposited on an LY12 Al alloy substrate using a microarc oxidation (MAO) process in a H3BO3–KOH electrolyte solution with the Na2WO4 addition varying from 0 to 6 g/l. The MAO process was studied by measuring the voltage as a function of time. The coating layers were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) with respect to the phases and microstructures and by measuring microhardness and wear resistance. The results show that the concentration of Na2WO4 has direct effects on the behavior of MAO process and the quality of the MAO coatings as well. The final phases in the coating were found to be α-Al2O3 and both γ-Al2O3 and a small amount of W. Without an addition of Na2WO4, the MAO coating process could not successfully proceed. With increasing the Na2WO4 concentration in the electrolyte, the working voltage at the microarc discharge stage decreased, the thickness and the content of α-Al2O3 phase in the coating both reduced. The microhardness and the wear resistance were both enhanced as the content of α-Al2O3 phase increased.

Ring- and single-crystal-like superstructures of Fe-doped PbTiO3 nanocrystals have been prepared by a simple hydrothermal method using (poly ethylene glycol) (PEG) as a surfactant. Two oriented-attachment forms of the nanocrystals favor the formation of the rings in view of geometry. Magnetism measurement shows that Fe-doped PbTiO3 sample is ferromagnetic even at room temperature. It is proposed that the magnetic dipole interactions and the presence of PEG molecules could together contribute to the formation of ring- and single-crystal-like superstructures composed of Fe-doped PbTiO3 nanocrystals.

Single-crystal SrTiO3 dendritic nanostructures were synthesized for the first time via a simple hydrothermal method without any surfactant. Structure characterizations suggest that the SrTiO3 dendrites show preferential orientation along [1 1 0]. Additionally, it is found that KOH concentration plays an important role in the formation of SrTiO3 dendrites, and the morphology of SrTiO3 crystallites can vary from cubic-like, star-like to dendritic shape. A rational mechanism is proposed to illustrate the growth of SrTiO3 dendrites.

Photodynamic therapy (PDT) and photothermal therapy (PTT) have been explored widely for application in cancer treatment. In this work, we describe the synthesis of CaTiO3:Yb,Er (CTO) nanofibers co-conjugated with Rose Bengal (RB) and gold nanorods (AuNRs), which offer the potential for combined upconversion photoluminescence (UCPL) and enhanced, synergistic PDT and PTT. Based on this delivery platform, RB and AuNRs served as the PDT and PTT agents, respectively. RB and AuNRs have strong and well-matched absorption with the green and red emissions of UCPL CTO nanofibers respectively, hence a single 980 nm continuous wave laser with deep tissue penetration can be employed to allow PDT and PTT to occur simultaneously. The nanocomposite can effectively convert the near-infrared (NIR) radiation from the laser into a combination of targeted hyperthermia and generation of reactive oxygen species (ROS). In comparison with PDT or PTT alone, the combined PDT/PTT treatment showed significantly enhanced suppression of the viability of Hep G2 cells in vitro, demonstrating its potential for use in oncology.

In this work, single-crystalline α-FeOOH nanorods with a length of 400–700 nm and a diameter of 20–80 nm were successfully synthesized via a facile template-free hydrothermal method. Single-crystalline mesoporous α-Fe2O3 and Fe3O4 nanorods could be obtained from these α-FeOOH precursors after calcining at 350 °C in air and 500 °C in nitrogen, respectively. The as-prepared single-crystalline mesoporous α-Fe2O3 and Fe3O4 nanorods exhibited a large specific surface area and porosity, effectively enhancing the electrochemical reaction area and accommodate the strain during the charge–discharge cycling process.

Single-crystal nanofibers of a new structured PbTiO3 with Zr doping concentration of 0–15% have been reproducibly synthesized on a large scale by a polymer-assisted hydrothermal method for the first time. Moreover, the Zr-doped new structured PbTiO3 nanofibers can transform into single-crystalline perovskite Pb(Zr, Ti)O3(PZT) nanofibers by annealing treatment in air.

Ferroelectric oxides with excellent electrical, mechanical and optical multifunctions play a vital role in future microdevices with diverse applications in energy, sensors and actuators. A series of Er doped PbZr0.52Ti0.48O3 (PZT:Er3+) nanofibers with tunable upconversion photoluminescence (PL) properties were successfully synthesized via a sol–gel based electrospinning process. By controlled crystallization, PZT:Er3+ nanofibers evolve from a polycrystalline to a single-crystalline-like structure, resulting in a remarkable increase in the visible upconversion emission intensity. It was uncovered that Er3+ doping site in PZT shifts from B site to A site with increase in crystallinity and crystal size. In addition, remarkable enhancement in red emission is observed with increased Er3+ doping concentration, which facilitates the modulation of emission colour from green to orange. Combined with the excellent ferroelectric properties of PZT, such spectral tunable PZT:Er3+ nanofibers are considered as a promising multifunctional candidate for integrated electro-mechano-optical devices.

Perovskite PbTiO3 (PTO) nanocrystals with a truncated octahedral morphology have been prepared by a facile solid-state reaction. Pt nanoparticles preferentially nucleated on the {111} facet of PTO nanocrystals exhibit a remarkable low-temperature catalytic activity towards CO oxidation from a temperature as low as 30 °C and achieve 100% conversion at ∼50 °C.

Octahedral-shaped perovskite PbTiO3 nanocrystals (PT OCT) with well-defined {111} facets exposed have been successfully synthesized via a facile hydrothermal method by using LiNO3 as an ion surfactant. The Li–O bond on the surface of PT OCT nanocrystals is essential to the stability of such nanocrystals and also results in a dramatic high visible-light photocatalytic activity.

3D flower-like PbTiO3 nanostructures self-assembled with (101) nanosheets have been realized by the hydrothermal treatment of the mixture of the lead and titanium hydroxides under the effect of high KOH concentration. The layered K2Ti6O13 formed in situ under the effect of the high KOH concentration plays an important role in the crystallization of the primary PbTiO3 nanosheets and the further self-assembly of the 3D flower-like perovskite PbTiO3 nanostructures. The self-assembled 3D flower-like perovskite PbTiO3 nanostructures express good mesoporous structures and high specific surface area. In consequence, the 3D flower-like perovskite PbTiO3 nanostructures as supports show excellent ability to enhance the catalytic activity of Pt. Over the Pt/PbTiO3 nanoflowers, the CO instantaneously completely converts to CO2 at a very low temperature of ca. 107 °C facilitating the catalytic purification of the automotive exhaust produced in the cold-start period.

750–850 nm (NIR I) and 1000–1400 nm (NIR II) in the near infrared (NIR) spectra are two windows of optical transparency for biological tissues with the latter capable of penetrating tissue deeper. Monitoring drug release from the drug carrier is still a daunting challenge in the field of nanomedicine. To overcome such a challenge, we propose to use porous Nd3+-doped CaTiO3 nanofibers, which can be excited by NIR I to emit NIR II light, to carry drugs to test the concept of monitoring drug release from the nanofibers by detecting the NIR II emission intensity. Towards this end, we first used electrospinning to prepare porous Nd3+-doped CaTiO3 nanofibers by adding micelle-forming surfactant Pluronic F127, followed by annealing to remove the organic component. After a model drug, ibuprofen, was loaded into the porous nanofibers, the drug release from the nanofibers into the phosphate buffered saline (PBS) solution was monitored by detecting the NIR II emission from the nanofibers. We found that the release of the drug molecules from the nanofibers into the PBS solution triggers the quenching of NIR II emission by the hydroxyl groups in the surrounding media. Consequently, more drug release corresponded to more reduction in the intensity of the NIR II emission, allowing us to monitor the drug release by simply detecting the intensity of NIR II from the nanofibers. In addition, we demonstrated that tuning the amount of micelle-forming surfactant Pluronic F127 enabled us to tune the porosity of the nanofibers and thus the drug release kinetics. This study suggests that Nd3+ doped CaTiO3 nanostructures can serve as a promising drug delivery platform with the potential to monitor drug release kinetics by detecting the tissue-penetrating NIR emission.