High performance perovskite solar cells using TiO2 nanospindles as ultrathin mesoporous layer

Single crystal anatase TiO2 nanospindles （NSs） with highly exposed {101} facets were synthesized and employed as electron transport materials （ETMs） in perovskite solar cells （PSCs）. Time-resolved photoluminescence （TRPL） spectra revealed that the TiO2 NSs are more effective than TiO2 nanoparticles in accepting electrons from perovskite. Moreover. the TiO2 nanospindles further endowed the PSCs with good reproducibility and suppressed hysteresis. The best device with TiO2 NSs as ETMs yielded power conversion efficiency （PCE） of 19.6%, demonstrating that the home-made TiO2 NSs is a good ETM for PSCs.

Fabrication of a Sensitive Electrochemical Biosensor for Detection of DNA Hybridization Based on Gold Nanoparti- cles/CuO Nanospindles Modified Glassy Carbon Electrode

In this work, a sensitive electrochemical DNA biosensor for the detection of sequence-specific target DNA was reported. Firstly, CuO nanospindles （CuO NS） were immobilized on the surface of a glassy carbon electrode （GCE）. Subsequently, gold nanoparticles （Au NPs） were introduced to the surface of CuO NS by the electrochemical deposition mode. Probe DNA with SH （HS-DNA） at the 5＇-phosphate end was covalently immobilized on the surface of the Au NPs through Au-S bond. Scanning electron microscopy （SEM） was used to elucidate the morphology of the assembled film, and electrochemical impedance spectroscopy technique （EIS） was used to investigate the DNA sensor assembly process. Hybridization detection of DNA was performed with differential pulse voltammetry （DPV） and the methylene blue （MB） was hybridization indicator. Under the optimal conditions, the decline of reduction peak current of MB （A/） was linear with the logarithm of the concentration of complementary DNA from 1.0 X 10-13 to 1.0× 10-6 mol·L l with a detection limit of 3.5 × 10 14 mol·L -1 （S/N=3）. In addition, this DNA biosensor has good selectivity, and even can distinguish single-mismatched target DNA.

Synthesis of RE(OH)_2Cl and REOCl (RE=Eu, Tb) nanostructures

Anisotropic structures, nanoneedles, and nanospindles of rare earth hydroxychloride （RE（OH）2Cl） and oxychloride （REOCl） （rare earth=Eu and Tb） were synthesized. The rare earth hydroxychloride nanostructures were formed via a thermally assisted hydrolysis of the rare-earth sesquioxide nanocrystals. The morphological evolution of the nanostructures was studied using high-resolution transmission electron microscopy and scanning electron microscopy, while the structural evolution was investigated using X-ray diffraction techniques. The thermal stability of the rare earth hydroxychlorides was investigated using thermogravimetric analysis. The rare earth oxychloride nanospindles were synthesized via a simple heat-treatment of rare earth hydroxychloride nanospindles.

Multi-shelled α-Fe_2O_3 microspheres for high-rate supercapacitors

Hollow structured metal oxides are extensively studied in energy storage and conversion systems. In this work, we report the fabrication of multi-shelled Fe_2O_3 microspheres with nanospindles assembly on its exterior shell. The β-FeOOH precursor nanospindles were firstly grown on the surface of carbon microspheres to produceβ-FeOOH@carbon composites, which were later converted into multi-shelled Fe_2O_3 microspheres by calcination in air.As electrode material for supercapacitors, the multi-shelled Fe_2O_3 microspheres exhibit high capacity and good rate capability. The electrode delivers the specific capacitances of630 and 510 F g^(-1) at the current densities of 1 and 5 A g^(-1),respectively.

Formation mechanism and magnetic properties of three different hematite nanostructures synthesized by one-step hydrothermal procedure

The spindle-like, tubular, and tire-like hematite were successively fabricated by a facile, one-step hydrothermal procedure, which is of great importance in facilitating the controllable-synthesis process of commercial industrialization. A mechanism involving a formation-dissolution process was proposed based on the X-ray diffraction, scanning electron microscopy, trans-mission electron microscopy, and high-resolution transmission electron microscopy analysis. It was demonstrated that the presence of phosphate ions during the reaction process is crucial to the morphology evolution of hematite. Their different ad-sorption ability on the different crystallographic planes of hematite and a coordination effect with ferric ions could promote the preferential dissolution of the spindle-like hematite precursors along the long axis [001] from the tips down to the interior, and thus yield the tubular and tire-like hematite one by one with the increasing reaction time. The magnetic measurements have also been performed to investigate the different magnetic properties such as coercivity and low-temperature transition behavior of three different hematite nanostructures.