Organometal halide perovskites, as promising semiconductor materials for achieving future low-cost optoelectronic devices, suffer from inherent instability and undergo extremely fast degradation under exposure to moisture, UV light, or high temperature. Herein, we present a facile and low cost approach for the preparation of perovskite-based composite films via blending CH3NH3PbBr3 nanocrystals (MAPbBr3 NCs) with two kinds of commercially available silicone resins. The highest photoluminescence quantum yield of the prepared composite films is up to 62%. The composite films of MAPbBr3 NCs with phenyl methyl silicon resin (PMSR) show unprecedented stability against water, heat and UV exposure. Their applications as paints or as phosphors for the fabrication of green and white light LEDs are demonstrated.

•Bi2O3 nanoparticles are prepared by using a facile thermal decomposition method.•Bi2O3 nanoparticles self assemble into well-shaped nanobelts.•Oleylamine and the size of nanoparticles play key roles in the formation of nanobelt.•A possible formation mechanism of the nanobelts was proposed.•Bi2O3 nanobelts shows good capacity to photo-degrading RhB under visible light irradiation.Bi2O3 nanoparticles are prepared by using a facile solution-based thermal decomposition method assisted by oleylamine. These Bi2O3 nanoparticles self assemble into nanobelts. The reaction time and temperature affect self-assembly behaviour of the Bi2O3 nanoparticles. Increasing the reaction time or temperature results in the larger size of nanoparticles, which leads to failure of formation of nanobelts. It is illustrated that oleylamine and the size of nanoparticles play key roles in the self-assembly of nanoparticles. Based on the experimental results, a formation mechanism of the self-assembled nanobelts was proposed and this method may be extended to fabrication of other metal oxide nanobelts.Download high-res image (152KB)Download full-size image

•MoS2 and WS2 nanosheets were chemically exfoliated from their bulk materials in nitrate/HCl.•The yield of MoS2 nanosheets reaches 58%.•The MoS2 nanosheets showed improved catalytic activity toward the oxygen reduction.•The MoS2 nanosheets exhibited excellent anticorrosion properties as a filler.An efficient nitrate/HCl chemical exfoliation system for rapid production of MoS2 and WS2 nanosheets were presented here. After exfoliation in the NaNO3/HCl solution with the assistant of ultrasonication, MoS2 and WS2 nanosheets were produced with yields of 58% and 52%, respectively. The morphologies and crystallinity of MoS2 and WS2 nanosheets were characterized by transmission electron microscopy, atomic force microscopy and X-ray diffraction spectroscopy. This efficient exfoliation method is based on the synergy effects of surface etching, insertion of ions and eruption of gas bubbles. The MoS2 and WS2 nanosheets exhibited improved catalytic activity toward the oxygen-reduction reaction.Download high-res image (372KB)Download full-size image

Combination of excellent optical properties and ferroelectricity of hybrid materials leads to high-performance optoelectronic devices. Here we present a new organic–inorganic hybrid compound (diisopropylammonium)2MnBr4 (DIPA2MnBr4) which shows high temperature ferroelectricity accompanied by highly efficient green-light emission. DIPA2MnBr4 also exhibits sensitive and selective optical response to alcohol vapors.

•Zr(OPr)4, ZnCl2 or MnCl2 reacted with [HMIM][HSO4] via anion exchange and resulted in the formation of imidazole template sulfates [HMIM]2Zr[SO4]3[DMSO]2 (1), [HMIM]2Zn[SO4]2 (2) and [HMIM]2Mn[SO4]2 (3), respectively.•Cu(OAc)2 interacted with imidazole to form imidazole-Cu complex [MIM]4Cu[HSO4]2 (4).•The imidazole template sulfates present various crystal structures, in which [HMIM]2Zr[SO4]3[DMSO]2 (1) has zero-dimensional monomeric structure made up of [Zr(SO4)3(DMSO)2]2− anions and [HMIM]+ cations. While, [HMIM]2Zn[SO4]2 (2) and [HMIM]2Mn[SO4]2 (3) exhibit one-dimensional metal–organic framework which consist of infinite linear chains linked by SO4 units.The reactions of metal salts with Bronsted acidic ionic liquid [HMIM][HSO4] in ethanol were investigated. Zr(OPr)4, ZnCl2 or MnCl2 reacted with [HMIM][HSO4] via an anion exchange and resulted in the formation of imidazole template sulfates [HMIM]2Zr[SO4]3[DMSO]2 (1), [HMIM]2Zn[SO4]2 (2) and [HMIM]2Mn[SO4]2 (3), respectively. On the other hand, Cu(OAc)2 interacted with imidazole to form an imidazole-Cu complex [MIM]4Cu[HSO4]2 (4). The imidazole template sulfates present various crystal structures, in which [HMIM]2Zr[SO4]3[DMSO]2 (1) has zero dimensional monomeric structure made up of [Zr(SO4)3(DMSO)2]2− anions and [HMIM]+ cations. While, [HMIM]2Zn[SO4]2 (2) and [HMIM]2Mn[SO4]2 (3) exhibit one dimensional metal–organic framework which consist of infinite linear chains linked by SO4 units. Compound 4 is an imidazole-metal complex, in which four imidazoles coordinate to Cu(II) to form tetragonal structure compensating the charges with protonated sulfates. Additionally, the magnetic property of compound 3 is investigated to find that it presents a weak antiferromagnetic property probably due to the coupling interactions between the neighboring Mn(II) centers.Zr(OPr)4, ZnCl2 or MnCl2 reacted with [HMIM][HSO4] via anion exchange and resulted in the formation of imidazole template sulfates [HMIM]2Zr[SO4]3[DMSO]2 (1), [HMIM]2Zn[SO4]2 (2) and [HMIM]2Mn[SO4]2 (3), respectively. On the other hand, Cu(OAc)2 interacted with imidazole to form imidazole-Cu complex [MIM]4Cu[HSO4]2 (4). The imidazole template sulfates present various crystal structures, in which [HMIM]2Zr[SO4]3[DMSO]2 (1) has zero-dimensional monomeric structure made up of [Zr(SO4)3(DMSO)2]2− anions and [HMIM]+ cations. While, [HMIM]2Zn[SO4]2 (2) and [HMIM]2Mn[SO4]2 (3) exhibit one-dimensional metal–organic framework which consist of infinite linear chains linked by SO4 units. Compound 4 is an imidazole-metal complex, in which four imidazoles coordinate to Cu(II) to form tetragonal structure compensating the charge with protonated sulfate.

We describe a chemical exfoliation method for the preparation of MoS2 nanosheets. The nanosheets were incorporated into poly(3,4-ethylenedioxythiophene) (PEDOT) by electrodeposition on a glassy carbon electrode (GCE) to form a nanocomposite. The modified GCE is shown to enable simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). Due to the synergistic effect of MoS2 and PEDOT, this electrode displays better properties in terms of electrocatalytic oxidation of AA, DA and UA than pure PEDOT, which is illustrated by cyclic voltammetry and differential pulse voltammetry (DPV). Under optimum conditions and at pH 7.4, the respective sensitivities and best working potentials are as follows: AA: 1.20 A∙mM−1∙m−2, 30 mV; DA: 36.40 A∙mM−1∙m−2, 210 mV; UA: 105.17 A∙mM−1∙m−2, 350 mV. The calculated detection limits for AA, DA and UA are 5.83 μM, 0.52 μM and 0.95 μM, respectively. The modified electrode was applied to the detection of the three species in human urine samples and gave satisfactory results.

•Water-soluble Gd-doped CdTe QDs were successfully synthesized by a one-step strategy.•The photoluminescence quantum yield of the prepared Gd:CdTe QDs was up to 42.5%.•Their function as a fluorescence-MRI dual model agent was illustrated.•The Gd:CdTe QDs have good biocompatibility and great potential for biomedical application.A facile one-pot strategy has been developed for the aqueous synthesis of Gd doped CdTe (Gd:CdTe) QDs as fluorescence and magnetic resonance imaging dual-modal agent. The prepared Gd:CdTe QDs showed narrow size distribution and the average size was less than 5 nm. The amount of Gd3+ dopant in Gd:CdTe QDs significantly affected the optical properties of obtained QDs. The highest PL QY for the prepared Gd:CdTe QDs was up to 42.5%. The QDs showed the weak toxicity and significant enhancement in MRI signal. The specific relaxivity value (r1) was determined to be 4.22 mM−1s−1. These properties make the prepared Gd:CdTe QDs be an effective dual-modal imaging agent and have great potential applications in biomedical field.

Four organic dyes based on indolo[3,2,1-jk]carbazole (IC-1, IC-2, IC-3, and IC-4) with different π-bridges (benzene ring and thiophene ring) are used for dye-sensitized solar cells (DSSCs) to investigate the effect of π-bridge on their photovoltaic performance. The introduction of thiophene ring as π-bridge (the dye IC-2) greatly improves the cell performance compared to benzene ring. The increasing conjugation length of the molecules decreases the performance of DSSCs. The best performance of DSSC based on IC-2 is obtained with a Voc of 0.66 V and a conversion efficiency of 3.68%. The poor performance of DSSCs based on IC-1 and IC-3 which contains only benzene ring as the π-bridge can be attributed to poor spectral coverage and higher electron charge transfer resistance as evaluated from EIS studies.

Pure phase bismuth nanospheres have been successfully prepared by thermolysis of bismuth acetate in oleylamine. The size distribution of the bismuth nanospheres was improved by quickly quenching the reaction as revealed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The ultraviolet–near-infrared (UV-NIR) absorbance spectrum of the bismuth nanospheres showed camel-like shapes located at 425 and 575 nm, which could be ascribed to the effect of the surface plasmon resonance and light scattering. Due to the absorption in the visible range, the prepared bismuth nanospheres showed good photocatalytic properties to the degradation of RhB.

A Ni/silicon microchannel plate (Ni/Si MCP) electrode modified with poly(3,4-ethylenedioxythiophene) (PEDOT) was successfully fabricated. The analytical performance of prepared electrode for the simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA) was investigated by using cyclic voltammetry and differential pulse voltammetry (DPV). The sensitivities for AA, DA and UA obtained by DPV are 5.39 A m−2 mM−1, 0.054 A m−2 μM−1 and 0.022 A m−2 μM−1, respectively. The calculated detection limits were 10 μM (AA), 1.5 μM (DA) and 2.7 μM (UA). The prepared electrode was successfully applied to the detection of AA, DA and UA in urine samples. The experiments illustrate that Ni/Si MCP is a good electrode material which provides a large surface-to-volume ratio and enhances the selectivity and sensitivity.

In this work, a facile method for the synthesis of pure phase BiFeO3 (BFO) nanoparticles with the microwave assistance was reported. BFO nanoparticles with high pure phase can be prepared in 20 min, which is much shorter than that of the traditional hydrothermal methods. The effect of microwave heating time on the phase purity of obtained samples was investigated in detail by using X-ray diffraction (XRD). An interesting phenomenon was observed that the pervoskite-type BFO with pure phase periodically appeared during the microwave heating process. The investigation of the magnetic properties of prepared samples also revealed the periodical formation of the pure phase BFO. The sample with a microwave heating time of 20 min shows a magnetization of 1.05 emu g−1 which is in accordance with the reported value.Highlights► Pure phase BiFeO3 nanoparticles were prepared with microwave assistance in 20 min ► Pure phase BiFeO3 formed, decomposed and reformed periodically during the microwave heating process. ► The special heating mechanism of microwave causes this phenomenon. ► The evolution of the magnetization testified the periodical formation of the pure phase BiFeO3.

A polythiophene functionalized with methylene blue (PMT-MB) was synthesized and used as an indicator for electrochemical oligonucleotides (ODNs) hybridization detection. After hybridization with complementary ODNs, the current signal of PMT-MB increased, which illustrated that PMT-MB can effectively recognize complementary ODN targets as an indicator. Compared to MB, PMT-MB showed much better resistance to the concentration change of buffer solution. In all buffer solutions tested, the hybridization always resulted in the increased current signal of PMT-MB due to the electrostatic interaction. While, when MB was used as an indicator, the inconsistent current response was obtained after the hybridization. When high concentration of buffer solution was used for accumulation, the hybridization resulted in the decreased current signal, while at the low concentrations, the current signal increased. The interaction between PMT-MB and dsODNs was also studied by UV–vis spectroscopy.Highlights► A cationic polymer, methylene blue (MB) functionalized polythiophene, was prepared. ► It was used as an electrochemical indicator for oligonucleotides hybridization detection. ► Compared to MB, This polymer shows much better resistance to the change of ionic strength. ► The dominated interaction of PMT-MB with ODN was investigated by UV–vis spectroscopy.

In this work, we systematically investigated the morphologies of polymers prepared by chemical oxidation of aniline and methyl-, methoxy-, or ethoxy-substituted aniline under the same experimental conditions. No matter the presence or absence of 10-camphorsulfonic acid (CSA), the oxidation of aniline produces nanotubes, while the oxidation of most aniline derivatives produce hollow microspheres under the same experimental conditions. These results illustrate the oligomers with phenazine-like structures produced at the initial oxidation of aniline are crucial for the formation of PANI nanotubes. The formation mechanism of the hollow microspheres of PANI derivatives is discussed. The main factors to control the polymer morphology are stability of droplets of aniline and its derivatives formed in an aqueous solution and the rate of exothermal reaction. The fast exothermal reaction benefits the formation of uniform microspheres. We also suggest that the hole on the surface of microspheres forms at the initial oxidation stage and is maintained by the flux of water and water-soluble components in the course of polymerization.

•DIPAB crystal with P21 phase is directly obtaned in solution at room temperature.•The water plays a key role in the phase of DIPAB crystal during crystallization.•A three-stage behavior of the dynamic hysteresis of DIPAB crystal is observed.The molecular ferroelectric, diisopropylammonium bromide (DIPAB) crystal with P21 phase is successfully prepared in an anhydrous environment at room temperature. The results illustrate that the water in the solvent / environment plays a key role in the phase of DIPAB single crystal during crystallization process. The scaling behavior of the dynamic hysteresis of DIPAB crystal is also investigated. The scaling relations of hysteresis area(A) against frequency (f) and applied electric field amplitude (E0) can be expressed with A∝f−0.17E01 in the f-region I (30–6.6 Hz), A∝f0.045E00.92 in the f-region II (200–50 Hz) and A∝f−0.41E02 in the f-region III (500–250 Hz). This three-stage behavior between the loop area A and frequency is ascribed to the coexistence of order-disorder and displacive characters in the ferroelectric transition characters in such molecular ferroelectrics.

Combination of excellent optical properties and ferroelectricity of hybrid materials leads to high-performance optoelectronic devices. Here we present a new organic–inorganic hybrid compound (diisopropylammonium)2MnBr4 (DIPA2MnBr4) which shows high temperature ferroelectricity accompanied by highly efficient green-light emission. DIPA2MnBr4 also exhibits sensitive and selective optical response to alcohol vapors.