查找使用阿拉丁产品的科研文献

In situ decorating of ultrasmall Ag2Se on upconversion nanoparticles as novel nanotheranostic agent for multimodal imaging-guided cancer photothermal therapy

Kaimin Du,Pengpeng Lei,Lile Dong,Manli Zhang,Xuan Gao,Shuang Yao,Jing Feng,Hongjie Zhang

A novel multifunctional theranostic nanoplatform was fabricated via in situ growth of ultrasmall Ag 2 Se nanodots on the surface of chitosan (CS) coated NaYF 4 :Yb/Er@NaLuF 4 :Nd/Yb@NaLuF 4 upconversion nanoparticles (UCNPs). NaYF 4 :Yb/Er@NaLuF 4 :Nd/Yb@NaLuF 4 @CS@Ag 2 Se (labeled as UCNPs@CS@Ag 2 Se) nanocomposites can provide downshifting (DS) and upconversion (UC) luminescence in NIR biological window I and II under 808-nm continuous-wave laser excitation simultaneously. Meanwhile, the attached Ag 2 Se nanodots could produce hyperthermia and photoacoustic energy upon 808-nm laser irradiation due to its strong near-infrared (NIR) absorbance. Together with the X-ray absorbance feature of lanthanide components, the nanocomposites with excellent luminescent properties, high X-ray attenuation coefficient and strong NIR absorbance could be utilized as a smart contrast agent for upconversion luminescence (UCL)/downshifting luminescence (DSL)/computer tomography (CT)/photoacoustic (PA) multimodal imaging in vitro and in vivo . Furthermore, the as-synthesized nanocomposites possess superior photothermal performance, good biocompatibility, and negligible toxicity, showing great potential as an ideal photothermal therapy (PTT) agent. These outstanding properties revealed that UCNPs@CS@Ag 2 Se nanocomposites are promising theranostic agents for tetra-modal imaging-guided PTT of cancer.

First application of CoO nanorods as efficient counter electrode for quantum dots-sensitized solar cells

Qiu Zhang,Zhanbin Jin,Fengyan Li,Zhinan Xia,Yi Yang,Lin Xu

For boosting the power conversion efficiency (PCE) of quantum dot sensitized solar cells (QDSSCs), metal oxide (CoO) has been prepared via a facile mean and applied for CE materials in CdS/CdSe/ZnS QDSSCs. The electrochemical properties of the CoO counter electrode (CE) and photovoltaic performances of QDSSCs are investigated in detail. Under analogous sunlight illumination, compared with traditional Cu 2 S CE, the QDSSCs fabricated with CoO CE showed an obvious enhancement in cell properties and increased the power conversion efficiency (PCE) by 32.7%. A PCE of 6.02% was achieved by the QDSSCs with CoO CEs, which deliver a short circuit current density (J sc ) of 20.42 mA/cm 2 , open circuit voltage (V oc ) of 0.655 V and fill factor (FF) of 0.45. Research so far has shown that metal oxide (e.g. CoO) has many excellent properties, such as good electrical conductivity , outstanding catalytic activity , relatively small charge transfer resistance , large surface area and cost-effective, so it is very promising to be a CE material for QDSSCs.

Electrospun Sb2Se3@C nanofibers with excellent lithium storage properties

Yan Dong,Yuezhan Feng,Jiwei Deng,Pengbin He,Jianmin Ma

Antimony-based materials have become promising anodes within lithium-ion batteries (LIBs) due to their low cost and the high theoretical capacity. However, there is a potential to further enhance the electrochemical performance of such antimony-based materials. Herein, Sb 2 Se 3 @C nanofibers (Sb 2 Se 3 @CNFs) are designed and obtained via a novel electrospinning method. Upon electrochemically testing as an anode within LIBs, the Sb 2 Se 3 @CNFs (annealed at 600 °C) delivers a remarkably good cycling performance of 625 mAh/g at 100 mA/g after 100 cycles. Moreover, it still remains at 490 mAh/g after 500 cycles with an applied current density of 1.0 A/g. The excellent performance of the Sb 2 Se 3 @CNFs can be attributed to the fact that the N-doped C matrices not only remit the volume expansion of materials, but also enhance the electrical and ionic conductivity thusly increasing the lithium-ion diffusion. The obtained Sb 2 Se 3 @CNFs are promising anode for LIBs in the future.

Mo doping induced metallic CoSe for enhanced electrocatalytic hydrogen evolution

Yan Zhou,Jingtong Zhang,Hao Ren,Yuan Pan,Youguo Yan,Fengchao Sun,Xueyuan Wang,Shutao Wang,Jun Zhang

Cation doping into 2D transition metal chalcogenides (TMC) is always interesting and meaningful, due to the possibilities of tuning both the crystal and electronic structures of TMCs. Herein, we used a mixed phase of CoSe/Co 9 Se 8 to facilitate the successful doping of Mo in CoSe crystal lattice. XRD, HRTEM, Raman spectroscopy and EXAFS analyses show a lattice contraction of Mo doped CoSe. Theoretical calculation confirms that Mo doping can lead to the lattice contraction of CoSe, and cause continuity shift of electron density of state toward Fermi level. We also demonstrated in this work, experimentally and theoretically, that the successful tuning of both crystal and electronic structure of CoSe upon on Mo doping leads to enhanced electrocatalytic HER performance in acidic condition. Co 0.8 Mo 0.2 Se showed the best HER activity, with only 186.1 mV overpotential needed to achieve 100 mA cm −2 current density and low Tafel slope of 58.7 mV dec -1 .

Enhancing monolayer photoluminescence on optical micro/nanofibers for low-threshold lasing

Feng Liao,Jiaxin Yu,Zhaoqi Gu,Zongyin Yang,Tawfique Hasan,Shuangyi Linghu,Jian Peng,Wei Fang,Songlin Zhuang,Min Gu,Fuxing Gu

Although monolayer transition metal dichalcogenides (TMDs) have direct bandgaps, the low room-temperature photoluminescence quantum yields (QYs), especially under high pump intensity, limit their practical applications. Here, we use a simple photoactivation method to enhance the room-temperature QYs of monolayer MoS2 grown on to silica micro/nanofibers by more than two orders of magnitude in a wide pump dynamic range. The high-density oxygen dangling bonds released from the tapered micro/nanofiber surface are the key to this strong enhancement of QYs. As the pump intensity increases from 10−1 to 104 W cm−2, our photoactivated monolayer MoS2 exhibits QYs from ~30 to 1% while maintaining high environmental stability, allowing direct lasing with greatly reduced thresholds down to 5 W cm−2. Our strategy can be extended to other TMDs and offers a solution to the most challenging problem toward the realization of efficient and stable light emitters at room temperature based on these atomically thin materials.

Ultrapure Green Light-Emitting Diodes Based on CdSe/CdS Core/Crown Nanoplatelets

Zuoliang Wen,Chaojian Zhang,Ziming Zhou,Bing Xu,Kai Wang,Kie Leong Teo,Xiao Wei Sun

Rapid ratiometric detection of Cd2+ based on the formation of ZnSe/CdS quantum dots

Zhi-Qiang Zhou,Yuan-Ping Liao,Jing Yang,Shan Huang,Qi Xiao,Li-Yun Yang,Yi Liu

Developing simple and sensitive non-aggregation strategy for detecting Cd 2+ is necessary for improving the selectivity and sensitivity of probe. Here, we establish a simple, rapid and ratiometric strategy for the recognition of Cd 2+ based on the formation of core-shell ZnSe/CdS structure using ZnSe quantum dots (QDs). The transformation from binary ZnSe QDs to core-shell ZnSe/CdS QDs both change the elemental composition and structure of ZnSe QDs, leading to the changes in band gap of ZnSe QDs, which could be observed in the UV–vis spectra. In the detection process, ZnSe QDs only possess absorption peak at 343 nm, the formation of ZnSe/CdS after the addition of Cd 2+ leads to the appearance of the new peak at 397 nm, while other heavy metal ions could not cause the appearance of new absorption peak. Therefore, this strategy shows good selectivity for Cd 2+ detection. Based on this strategy, the limit of detection (LOD) for Cd 2+ is 11 nM by UV–vis spectroscopy with a desirable relation of linearity (R 2  = 0.999) between A 397 /A 343 and Cd 2+ contents, which is superior to the LOD of most reported nanomaterials . The response time for Cd 2+ detection is as short as 60 s, which is suitable for rapid detection. This ratiometric probe has also been applied to the detection of Cd 2+ in tap water samples, the recovery of Cd 2+ was between 94.9% and 105.6% for tap water samples, indicating the high accuracy of our ratiometric assay. Our strategy not only provided a new method for detecting Cd 2+ , but also put forward an implication that the band energy changes of QDs caused by heavy metal ions can be applied in the selective and sensitive detection of heavy metal ions.

Soft-Chemical Method for Synthesizing Intermetallic Antimonide Nanocrystals from Ternary Chalcogenide

Yilan Jiang,Long Yuan,Yanyan Xu,Jiaojiao Ma,Yu Sun,Xia Gao,Keke Huang,Shouhua Feng

The synthesis of intermetallic antimonides usually depends on either the high-temperature alloying technique from high-purity metals or the flux method in highly poisonous Pb-melt. In this paper, we introduced a soft-chemical method to synthesize intermetallic antimonides from ternary chalcogenide precursors under an argon atmosphere below 200 °C. Powder X-ray diffraction and compositional analysis clearly indicate that a new phase of the Ag3Sb nanocrystal was synthesized from the Ag3SbS3 precursors. Three types of trialkylphosphines (TAPs) were applied as desulfurization agents, and the transformation mechanism was elucidated. The capability of the desulfurization agent follows the sequence of triphenylphosphine (TPP) > tributylphosphine (TBP) > trioctylphosphine (TOP). Besides, this TAP-driven desulfurization route to synthesize the intermetallic phase could also be possible for AgSbSe2 and Sb2S3. Therefore, this paper provides an efficient and mild technique for the fabrication of intermetallic nanocrystals.

Construction of hierarchical cobalt-molybdenum selenide hollow nanospheres architectures for high performance battery-supercapacitor hybrid devices

Fei Ma,Jinghua Lu,Linyu Pu,Wei Wang,Yatang Dai

Transition metal selenides have aroused widespread attention as a class of emerging electrode materials for high-performance supercapacitors attributed to their featured with high theoretical capacitance and low electronegativity. Nevertheless, their practical applications are seriously restricted by the large volume expansion during high-rate charge/discharge. It is imperative to reasonably construct tunable composition and attractive architectures for electrode materials at nanoscale to mitigate the issues. Herein, hierarchical cobalt-molybdenum selenide (denoted as CoSe 2 /MoSe 2 -3-1) hollow nanospheres architectures are purposefully prepared via an efficient gas bubble-templated method combined with post-annealing process. Benefiting from the rationally hierarchical hollow structures and maximized utilization ratio of active materials, the novel bimetallic selenides acquire superior electrochemical performance with high specific capacity (211.97 mA h g −1 at 1 A g −1 ) and remarkable cycling stability (94.2% capacity retention over 2000 cycles at 3 A g −1 ). Significantly, the assembled CoSe 2 /MoSe 2 -3-1//activated carbon (AC) battery-supercapacitor hybrid (BSH) device renders a high energy density up to 51.84 W h kg −1 at a power density of 799.2 W kg −1 and preeminent cycling stability with 93.4% retention over 10,000 cycles. The present work provides an effective and rational design route to engineer advanced bimetallic selenides with hierarchical hollow structures for electrochemical energy storage and conversion.

Construction of ternary CdxMo1−xSe quantum dots for enhanced photocatalytic hydrogen production

Han Jishu,Liu Ying,Wang Ying,Zhao Ruiyang,Wang Lei

The development of novel photocatalyst is an important issue for improving the photocatalytic hydrogen production efficiency. Herein, novel aqueous ternary Cd x Mo 1− x Se quantum dots (QDs) are prepared with five ratios ( x  = 0, 0.5, 0.67, 0.75, 1) by modulating the metal content. Experimental results show that the doping of Mo promotes the photoinduced electrons transfer and decreases the photoinduced electron–hole pairs recombination. Compared with the CdSe QDs, Cd 0.75 Mo 0.25 Se QDs, Cd 0.5 Mo 0.5 Se QDs and MoSe 2 QDs, Cd 0.67 Mo 0.33 Se QDs exhibit significantly enhanced photocatalytic activity, and the amount of H 2 production comes up to 911.1 μmol in 7 h. Meanwhile, the Cd 0.67 Mo 0.33 Se QDs display substantially high stability in recycling test, which facilitates the utilization of ternary QDs in the photocatalytic hydrogen production application.

Engineering Ni2P-NiSe2 heterostructure interface for highly efficient alkaline hydrogen evolution

Caichi Liu,Tao Gong,Jun Zhang,Xuerong Zheng,Jing Mao,Hui Liu,Ying Li,Qiuyan Hao

Developing earth-abundant transition-metal phosphides electrocatalysts with high activity and good durability toward alkaline hydrogen evolution reaction (HER) is crucial for sustainable hydrogen energy economy. However, their intrinsic activity is limited by the inadequate hydrogen adsorption energy. Herein, we reported a novel self-supported heterostructure catalyst in the form of Ni 2 P-NiSe 2 , which is obtained by phosphorization of NiSe 2 nanosheet arrays grown on the carbon cloth. The heterostructure catalyst exhibits excellent HER performance in 1 M KOH, only requiring an overpotential of 66 mV at a current density of 10 mA cm −2 with a Tafel slope of 72.6 mV dec -1 and showing excellent long-term durability. The experimental and theoretical calculation results demonstrate the strongly electronic interaction between Ni 2 P and NiSe 2 , resulting in the optimized Gibbs free energy of hydrogen and water adsorption. This work concerning the regulation of electronic structure through interface engineering may offer a deep insight to explore superior catalysts.

“Turn off-on” fluorescent sensor based on quantum dots and self-assembled porphyrin for rapid detection of ochratoxin A

Li Liu,Qingwen Huang,Zafar Iqbal Tanveer,Keqiu Jiang,Jinghui Zhang,Hongye Pan,Lianjun Luan,Xuesong Liu,Zheng Han,Yongjiang Wu

We report herein a “turn off-on” fluorescent sensor based on ZnCdSe quantum dots (ZnCdSe QDs) and self-assembled zinc porphyrin for sensitive and rapid detection of ochratoxin A (OTA). Using environmentally friendly dodecyl dimethyl betaine as “soft template”, zinc 5, 10, 15, 20-tetra(4-pyridyl)-21H-23H-porphine (ZnTPyP) was self-assembled into nanorods (SA-ZnTPyP) through a green process. The OTA detection process involves two steps: (1) the fluorescence of ZnCdSe QDs is significantly quenched by SA-ZnTPyP, and (2) the combination between SA-ZnTPyP and OTA releases ZnCdSe QDs from their quenchers such that the fluorescence is recovered. Under the optimized experimental conditions, the newly developed fluorescent sensor showed a linear response in concentration range 0.5–80 ng mL −1 , with a detection limit of 0.33 ng mL −1 . The excellent applicability of the system has been verified in milk and coffee samples, with relative recoveries between 98.33% and 103.70%. The proposed fluorescent sensor exhibits excellent selectivity and high sensitivity, and thus could be a promising tool for on-site determination of OTA in food safety control and environmental monitoring.