Yonglei Xing

Highly Efficient Flexible Perovskite Solar Cells Using Solution-Derived NiOx Hole Contacts

A solution-derived NiOx film was employed as the hole contact of a flexible organic-inorganic hybrid perovskite solar cell. The NiOx film, which was spin coated from presynthesized NiOx nanoparticles solution, can extract holes and block electrons efficiently, without any other post-treatments. An optimal power conversion efficiency (PCE) of 16.47% was demonstrated in the NiOx-based perovskite solar cell on an ITO-glass substrate, which is much higher than that of the perovskite solar cells using high temperature-derived NiOx film contacts. The low-temperature deposition process made the NiOx films suitable for flexible devices. NiOx-based flexible perovskite solar cells were fabricated on ITO-PEN substrates, and a preliminary PCE of 13.43% was achieved.

High efficiency hysteresis-less inverted planar heterojunction perovskite solar cells with a solution-derived NiOx hole contact layer

A hysteresis-less inverted planar heterojunction perovskite solar cell with 14.42% power conversion efficiency (PCE) was successfully fabricated by employing a solution-derived NiOx film as the hole selective contact. Here, the non-stoichiometric transparent NiOx film is composed of a lot of small NiOx nanocrystals with a cubic crystal structure. Inverted planar heterojunction perovskite solar cells based on the as-prepared NiOx hole selective contacts show a much higher PCE and air storage stability than the control device fabricated from the PEDOT:PSS film as the hole selective contact, since NiOx has a better electron blocking property due to its high conduction band edge position. The thickness of the NiOx contact strongly influences the performance of the NiOx-based perovskite solar cells, which include the PCE, hysteresis behaviors and air storage stability due to the thickness-dependent morphology of the NiOx contact.

Facile synthesis of ZnO/CuInS2 nanorod arrays for photocatalytic pollutants degradation.

Vertically-aligned ZnO nanorod arrays on a fluorine-doped tin oxide glass substrate were homogeneously coated with visible light active CuInS2 quantum dots by using a controllable electrophoretic deposition strategy. Compared with the pure ZnO nanorod arrays, the formation of high-quality ZnO/CuInS2 heterojunction with well-matched band energy alignment expanded the light absorption from ultraviolet to visible region and facilitated efficient charge separation and transportation, thus yielding remarkable enhanced photoelectrochemical performance and photocatalytic activities for methyl orange and 4-chlorophenol degradation. The ZnO/CuInS2 film with the deposition duration of 80min showed the highest degradation rate and photocurrent density (0.95mA/cm(2)), which was almost 6.33 times higher than that of the pure ZnO nanorod arrays film. The CuInS2 QDs sensitized ZnO nanorod arrays film was proved to be a superior structure for photoelectrochemical and photocatalytic applications due to the optimized CuInS2 loading and well-maintained one-dimensional nanostructure.

Fabrication of Bi2Sn2O7-ZnO heterostructures with enhanced photocatalytic activity

ZnO microspheres synthesized by a hydrolysis method were sensitized with Bi2Sn2O7 (BSO) nanoparticles prepared using a hydrothermal method at different concentrations. Various characterization methods were employed to study the microstructural, morphological, optical and photocatalytic properties of the BSO-ZnO heterostructures. The effect of the BSO concentration on the photocatalytic activity of the as-prepared samples was also investigated. The 12.5BSO-ZnO sample exhibits the highest photocatalytic efficiency. The enhanced photocatalytic efficiency is ascribed to an effective separation of the photogenerated electrons and holes due to the presence of the BSO-ZnO heterojunction.

Bi2Sn2O7–TiO2 nanocomposites for enhancing visible light photocatalytic activity

Bi2Sn2O7–TiO2 nanocomposites with different ratios of Bi2Sn2O7 (BSO) and TiO2 were prepared by combining a facile co-precipitation method with the aid of a template. X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy were employed to characterize the physicochemical properties of the as-prepared nanocomposites. The band gap energies of the nanocomposites were established by diffuse reflectance UV-Vis spectra. The specific surface area and average pore diameter of the nanoparticles were measured by an N2 adsorption–desorption isotherm. Photocatalytic degradation of Rhodamine B dye molecules was also investigated in the visible region so as to explore the photocatalytic activity of the as-prepared nanocomposites. The results showed that the 10BSO–TiO2 nanocomposites had a remarkably enhanced photocatalytic performance as compared with other samples including anatase TiO2. It was also found that all BSO modified TiO2 samples had a wider band gap energy than the pure BSO sample, but showed a higher photocatalytic activity than the pure BSO sample due to the photosensitization mechanism of the dye molecules.

Crack-free polydimethylsiloxane–bioactive glass–poly(ethylene glycol) hybrid monoliths with controlled biomineralization activity and mechanical property for bone tissue regeneration

Crack-free organic-inorganic hybrid monoliths with controlled biomineralization activity and mechanical property have an important role for highly efficient bone tissue regeneration. Here, biomimetic and crack-free polydimethylsiloxane (PDMS)-modified bioactive glass (BG)-poly(ethylene glycol) (PEG) (PDMS-BG-PEG) hybrids monoliths were prepared by a facile sol-gel technique. Results indicate that under the assist of co-solvents, BG sol and PDMS and PEG could be hybridized at a molecular level, and effects of the PEG molecular weight on the structure, biomineralization activity, and mechanical property of the as-prepared hybrid monoliths were also investigated in detail. It is found that an addition of low molecular weight PEG can significantly prevent the formation of cracks and speed up the gelation of the hybrid monoliths, and the surface microstructure of the hybrid monoliths can be changed from the porous to the smooth as the PEG molecular weight increases. Additionally, the hybrid monoliths with low molecular weight PEG show the high formation of the biological apatite layer, while the hybrids with high molecular weight PEG exhibit negligible biomineralization ability in simulated body fluid (SBF). Furthermore, the PDMS-BG-PEG 600 hybrid monolith has significantly high compressive strength (32 ± 3 MPa) and modulus (153 ± 11 MPa), as well as good cell biocompatibility by supporting osteoblast (MC3T3-E1) attachment and proliferation. These results indicate that the as-prepared PDMS-BG-PEG hybrid monoliths may have promising applications for bone tissue regeneration.

Enhanced Conversion Efficiencies in Dye-Sensitized Solar Cells Achieved through Self-Assembled Platinum(II) Metallacages.

Two-component self-assembly supramolecular coordination complexes with particular photo-physical property, wherein unique donors are combined with a single metal acceptor, can be utilized for many applications including in photo-devices. In this communication, we described the synthesis and characterization of two-component self-assembly supramolecular coordination complexes (SCCs) bearing triazine and porphyrin faces with promising light-harvesting properties. These complexes were obtained from the self-assembly of a 90° Pt(II) acceptor with 2,4,6-tris(4-pyridyl)-1,3,5-triazine (TPyT) or 5,10,15,20-Tetra(4-pyridyl)-21H,23H-porphine (TPyP). The greatly improved conversion efficiencies of the dye-sensitized TiO2 solar cells were 6.79 and 6.08 respectively, while these SCCs were introduced into the TiO2 nanoparticle film photoanodes. In addition, the open circuit voltage (Voc) of dye-sensitized solar cells was also increased to 0.769 and 0.768 V, which could be ascribed to the inhibited interfacial charge recombination due to the addition of SCCs.

New architecture of a petal-shaped Nb2O5 nanosheet film on FTO glass for high photocatalytic activity

A petal-shaped Nb2O5 nanosheet thin film was grown directly on a transparent conductive fluorine-doped tin oxide (FTO) glass substrate via a facile hydrothermal method. Structural and morphological characterization showed that the Nb2O5 nanosheets with a thickness of about 30 nm stood almost vertically on the FTO glass substrate. The vertical thickness of the petal-shaped Nb2O5 nanosheet array film, which grows along (020) and (003) crystal planes, was 2–3 μm. The petal-shaped Nb2O5 nanosheet array film on FTO glass without annealing showed excellent photocatalytic activity for degrading aqueous rhodamine B. The activity was better than that of the porous P25 film with a thickness of 50 μm. The new architecture is suitable for reuse in photocatalytic applications.

Content-dependent biomineralization activity and mechanical properties based on polydimethylsiloxane–bioactive glass–poly(caprolactone) hybrids monoliths for bone tissue regeneration

In this study, polydimethylsiloxane–bioactive glass–poly(caprolactone) (PDMS–BG–PCL) hybrid monoliths with various PDMS–BG contents were successfully fabricated via a typical sol–gel route. As a reinforcement, the PDMS–BG was used to improve the biomineralization activity, mechanical properties and osteoblasts biocompatibility of PCL polymer. The incorporation of PCL significantly decreased the formation time and increased the toughness of crack-free PDMS–BG–PCL hybrid monoliths. The mechanical properties of PDMS–BG–PCL hybrid monoliths were significantly affected by the content of PDMS–BG and PDMS–BG–PCL (30 wt%) showed a much higher elastic modulus (328.87 ± 18.82 MPa). The hydrophilicity of PDMS–BG–PCL hybrids was also increased as the PDMS–BG increased. Additionally, the biomineralization activity of PDMS–BG–PCL hybrid monoliths could be tailored by the PDMS–BG content. All PDMS–BG–PCL hybrids could induce fast deposition of a crystalline apatite layer on their surface in SBF for 7 days. The in vitro cellular studies also showed that PDMS–BG–PCL hybrids can enhance osteoblasts attachment and cell viability compared with PCL. The crack-free monolith structure, biomimetic hybrid composition and high apatite-forming bioactivity make PDMS–BG–PCL hybrid a promising candidate as scaffolds and implants for drug delivery and bone regeneration applications.

Fabrication of Ag2O–Bi2Sn2O7 Heterostructured Nanoparticles for Enhanced Photocatalytic Activity

Ag2O-Bi2Sn2O7 composites were prepared by a chemical co-precipitation method. The microstructural, morphological and optical properties of the as-prepared composites were characterized and studied. Effects of Ag2O contents on photocatalytic activity of the Ag2O-Bi2Sn2O7 composites were also investigated in detail. Compared with pure Bi2Sn2O7, the 0.03Ag2O-Bi2Sn2O7 composite exhibits the highest photocatalytic activity for the degradation of Rhodamine B aqueous solution under visible light irradiation. The enhanced photocatalytic activity of the Ag2O-Bi2Sn2O7 composite can be attributed to the existence of the Ag2O-Bi2Sn2O7 heterojunction, which is propitious to an effective separation of the photogenerated electron-hole pairs.