查找使用阿拉丁产品的科研文献

DFT insights into the selective NH3 sensing mechanism of two dimensional ZnTe monolayer

Xiao Chang,Xiaofang Li,Qingzhong Xue

Exploring novel NH3 sensing materials is crucial in chemical industries, fertilizing plants and medical fields. Herein, for the first time, the NH3 sensing behaviors and sensing mechanisms of two dimensional (2D) ZnTe monolayer are systematically investigated by density functional theory calculations. It is shown that 2D ZnTe monolayer exhibits excellent selective NH3 sensing properties. (220) crystal facet of ZnTe possesses a higher NH3 adsorption energy (−1.59 eV) and a larger charge transfer (0.195e) than (111) and (311) crystal facets. The positive charges could enhance NH3 sensing while the negative charges could reduce NH3 sensing. The NH3 adsorption strengths are significantly improved in O2 atmosphere while it is negligibly affected by N2 atmosphere and H2O atmosphere. Moreover, the presence of Zn vacancy and Fe, Co, Ni doping could improve the NH3 sensing of ZnTe. Additionally, the experimental results confirms that ZnTe possesses a low detection limit of 0.1 ppm NH3. These theoretical predictions and experimental results present a wide range of possibilities for the further development of ZnTe monolayer in NH3 sensing fields.

Nanocluster-Mediated Synthesis of Diverse ZnTe Nanostructures: from Nanocrystals to 1D Nanobelts

Jiaojiao Zheng,Meng Xu,Jia Liu,Xiaoyan Cheng,Jiajia Liu,Hongpan Rong,Jiatao Zhang

Graphical Nano nano : Considering the difficulty of direct nucleation-growth, monodisperse ZnTe nanoclusters were chosen to mediate the seed growth and oriented attachment mechanism to synthesize the flexible ZnTe nanostructures, from monodisperse dendrimer-like nanocrystals to flexible 1D tens-of-micrometers-length nanobelts. Liquid phase one-pot synthesis of semiconductor nanocrystals, by direct nucleation-growth crystallization, is unsuccessful for synthesis of some kinds of semiconductors. Using ZnTe as an example here, highly disperse ZnTe nanoclusters with diameters of 2–3 nm were first synthesized by a facile solvothermal method. Then the ZnTe nanoclusters were chosen as starting crystallization seeds to mediate the synthesis of flexible semiconductor nanostructures. Three-dimensional (3D) oriented assembly of ZnTe nanoclusters to monodisperse dendrimer-like nanocrystals (DLNCs), and one-dimensional (1D) ZnTe nanobelts with cubic phase, have been achieved successfully. Supported by TEM characterization of time-dependent morphology evolution, the oriented attachment assisted seed growth, based on ZnTe nanoclusters, enabled the 1D flexible ZnTe nanobelts formation, which could reach to ≈10 micrometers length.

Visible-light-driven Z-scheme ZnTe/WO3 heterojunction for simultaneous elimination of tetracycline and Cu(II)

Hongyan Zhang,Jiehui Huang,Yuxiang Shen,Zuofang Yao,Chenchen Xing,Yanping Hou

Z-Scheme heterojunction photocatalysts can effectively suppress the recombination of charge carriers while maintaining high redox capacity. In this study, ZnTe/WO 3 (ZW) Z-scheme heterojunction photocatalysts were synthesized using a hydrothermal method, and a series of photocatalytic materials were prepared for the simultaneous removal of tetracycline (TC) and Cu(II) from water. The physicochemical and photoelectrochemical properties of the catalytic materials were characterized through various methods, including SEM, XRD, XPS, and others. The experimental results indicate that the ZW-10 % composite material exhibits the most significant removal efficiency for pollutants. Within 150 min of visible light irradiation, the removal rates for TC and Cu(II) reach 73.8 % and 73.3 %, respectively, representing a substantial improvement compared to individual ZnTe and WO 3 . Free radical capture experiments and electron spin resonance analysis reveal that ·O 2 − and ·OH are the key reactive species responsible for TC oxidation, while electrons (e − ) dominate the reduction of Cu(II).

ZnTe quantum dots as fluorescence sensors for the detection of iron ions

Xing Xiaowei,Wang Dongming,Chen Zhi,Zheng Bodan,Li Baohong,Wu Dudu

Colloidal mercaptoacetic acid capped ZnTe quantum dots (QDs) are prepared to target iron ions as a fluorescence sensor. The results show that the obtained QDs present excellent selectivity for the detection of Fe 3+ and display a good linearity from 2.0 × 10 − 6 to 1.0 × 10 − 4  mol L − 1 . The optimum fluorescence intensity for detecting Fe 3+ is found in a buffer (pH 7.0) at 25 °C. The detection limitation of Fe 3+ ions is 4.89 × 10 − 6  mol L − 1 under optimized conditions. The quenching rate constant K q (1.24 × 10 13  L mol − 1  s − 1 ) is calculated and confirmed to describe a static quenching procedure. Moreover, the obtained probes are used to detect Fe 3+ ions in lake water samples, showing perspectives of environmental determination for future research.

Aqueous synthesis of high-fluorescence ZnTe quantum dots

Cheng Tao,Li Dongmei,Li Jie,Ren Bing,Wang Gang,Cheng Jingwei

High fluorescence ZnTe quantum dots (QDs) were prepared by one-step aqueous method in faintly acid solution. The detailed microstructure and morphology of the prepared ZnTe QDs has been characterized by X-ray powder diffraction and high resolution transmission electron microscopy, respectively. The average size of as-prepared ZnTe QDs is about 5 nm, which is hexagonal wurtzite structure. The PL spectra consists of a strong peak around 550 nm originating from surface state emission and a weak peak around 470 nm via band edge emission. Meanwhile, ZnTe/ZnSe QDs were prepared by passivating ZnSe shell on surface of ZnTe core, which effectively prevent the Tellurium ion oxidation to reduce the zinc carrier trap and the emission peak at about 470 nm has been strengthened. ZnTe/ZnSe QDs show a higher quantum yield (21.90 %) than ZnTe QDs (10.19 %). Moreover, ZnTe/ZnSe QDs exhibit excellent stability against time.

Formation and Transformation of ZnTe and CdTe Magic-Size Clusters Assisted by Their Precursor Compounds

Zhe Wang,Chunchun Zhang,Shanling Wang,Meng Zhang,Xiaoqin Chen,Chaoran Luan,Kui Yu

Colloidal semiconductor magic-size clusters (MSCs) remain poorly understood with regard to their formation and transformation. We show that ZnTe MSC-324 (with an optical absorption peak at 324 nm) and MSC-398 evolve in reactions of Zn and Te precursors, while CdTe MSC-371 and MSC-481 develop in reactions of Cd and Te precursors. We propose that MSCs evolve from their precursor compounds (PCs). Chemical self-assembly results in the formation of ZnTe PC-324 and CdTe PC-371, which, respectively, transform to ZnTe PC-398 and CdTe PC-481 via monomer addition. When the ZnTe MSCs are mixed with Cd(OAc)2/OLA (cadmium acetate in oleylamine), the CdTe MSCs also evolve. We further hypothesize that cation exchange occurs on the ZnTe PCs, resulting in CdTe PCs that transform to their counterpart CdTe MSCs. Moreover, ZnTe PC/MSC-324 and CdTe PC/MSC-371 have similar Zn/Cd-to-Te stoichiometries, as do ZnTe PC/MSC-398 and CdTe PC/MSC-481. Accordingly, the Te precursor quantitatively dictates the coassembly of Zn or Cd and Te precursors as well as the monomer addition. The present findings advance the understanding of the initial PC formation, PC-to-PC transformation, PC-to-MSC isomerization, and PC-to-monomer fragmentation.

Bifunctional ZnTe Enables Top-Illuminated p-on-n PbS Quantum Dot Infrared Photodetectors and Imagers

Xi Ran,Hang Xia,Jing Liu,Mohan Yuan,Xudong Hu,Ya Wang,Xinzheng Lan

Lead sulfide (PbS) colloidal quantum dot (CQD) photodetectors are promising devices for low-cost, high-performance, and large-area infrared imaging. For integration with readout integrated circuits (ROICs), top illumination is urgently required to ensure simultaneous light absorption and signal acquisition. However, the traditional best-performing p-on-n PbS CQD photodetectors rely on opaque top metal contacts, thus limiting the development of top-illuminated imagers. Herein, we addressed this issue by introducing a bifunctional ZnTe layer. The presence of the ZnTe layer─while allowing efficient hole collection─serves as a protective layer for the CQD layer during subsequent transparent electrode deposition. The resultant PbS CQD photodetectors based on the ZnTe layer show a specific detectivity of 2.09 × 1012 Jones at ≈1300 nm, representing approximately a 5-fold improvement over the control device (4.30 × 1011 Jones). This performance is comparable to that of the best PbS CQD photodetectors reported at similar wavelengths. The advantages of this architecture are further demonstrated by building a PbS CQD imager with a pixel array of 256 × 256, verifying the compatibility of photodetectors with ROICs.

Broadband Optical Non-linearity Induced by Charge-Transfer Excitons in Type-II CdSe/ZnTe Nanocrystals

Yunlong Liu,Chunfeng Zhang,Huichao Zhang,Rui Wang,Zheng Hua,Xiaoyong Wang,Jiayu Zhang,Min Xiao

Graphical Benefiting from excitonic charge-transfer states, an efficient non-linear optical response is observed in type-II nanocrystals by four-wave mixing when the incident photon energy lies below the bandgaps of constituent semiconductors. The non-linear optical properties in nanocrystals can be manipulated by the band alignment of the core–shell components, which serves as a promising platform to design broadband non-linear optical devices.

Exploiting bifunctional ZnTe for Zn anode protection and conversion-type cathode toward compatible aqueous Zn-ion batteries

Dawei Sha,Chengjie Lu,Rongxiang Hu,Zhuoheng Bao,Long Pan,ZhengMing Sun

Aqueous zinc-ion batteries (AZIBs) offer an attractive solution for grid-scale energy storage but suffer from a significant challenge in finding advanced Zn anodes and cathodes that are mutually compatible. Here we propose tellurides, specifically ZnTe, as a multifunctional material that can simultaneously serve as a Zn anode protective layer and a cathode material with excellent compatibility and performance. Theoretical analyses disclose that ZnTe possesses high electronic conductivity, favorable Zn 2+ adsorption and diffusion, and structural stability upon Zn 2+ insertion, which are fundamental to Zn anode protection and Zn 2+ storage. Experimental findings reveal that ZnTe effectively protects Zn anodes from dendrite growth and surface corrosion, resulting in a minimal voltage hysteresis of only 38 mV over 3100 h at 1 mA cm –2 . Additionally, the ZnTe cathode exhibits a conversion-reaction mechanism of ZnTe ⇄ ZnTe 2 ⇄ Te, with excellent plateau capacities. We also demonstrate the good compatibility between ZnTe-based anodes and cathodes by assembling full cells that deliver exceptional cyclability (80 % capacity retention at 2 A g –1 over 1000 cycles). Our work provides a general design guideline for compatible and advanced electrode materials for AZIBs.

Band Engineering in Core/Shell ZnTe/CdSe for Photovoltage and Efficiency Enhancement in Exciplex Quantum Dot Sensitized Solar Cells

Shuang Jiao,Qing Shen,Iván Mora-Seró,Jin Wang,Zhenxiao Pan,Ke Zhao,Yuki Kuga,Xinhua Zhong,Juan Bisquert

Even though previously reported CdTe/CdSe type-II core/shell QD sensitizers possess intrinsic superior optoelectronic properties (such as wide absorption range, fast charge separation, and slow charge recombination) in serving as light absorbers, the efficiency of the resultant solar cell is still limited by the relatively low photovoltage. To further enhance photovoltage and cell efficiency accordingly, ZnTe/CdSe type-II core/shell QDs with much larger conduction band (CB) offset in comparison with that of CdTe/CdSe (1.22 eV vs 0.27 eV) are adopted as sensitizers in the construction of quantum dot sensitized solar cells (QDSCs). The augment of band offset produces an increase of the charge accumulation across the QD/TiO2 interface under illumination and induces stronger dipole effects, therefore bringing forward an upward shift of the TiO2 CB edge after sensitization and resulting in enhancement of the photovoltage of the resultant cell devices. The variation of relative chemical capacitance, Cμ, between ZnTe/CdSe and reference CdTe/CdSe cells extracted from impedance spectroscopy (IS) characterization under dark and illumination conditions clearly demonstrates that, under light irradiation conditions, the sensitization of ZnTe/CdSe QDs upshifts the CB edge of TiO2 by the level of ∼50 mV related to that in the reference cell and results in the enhancement of Voc of the corresponding cell devices. In addition, charge extraction measurements have also confirmed the photovoltage enhancement in the ZnTe/CdSe cell related to reference CdTe/CdSe cell. Furthermore, transient grating (TG) measurements have revealed a faster electron injection rate for the ZnTe/CdSe-based QDSCs in comparison with the CdSe cells. The resultant ZnTe/CdSe QD-based QDSCs exhibit a champion power conversion efficiency of 7.17% and a certified efficiency of 6.82% under AM 1.5G full one sun illumination, which is, as far as we know, one of the highest efficiencies for liquid-junction QDSCs.

Fluorescence Probe for Detection of Paeoniflorin Using ZnTe Quantum Dots

Bodan Zheng,Baohong Li,Zhi Chen,Xiaowei Xing,Dudu Wu

Stable Near-Infrared Light and Microcavity of the ZnTe Microbelt and Different Emission Behaviors

Yongbo Zhou,Ye Tian,Arfan Bukhtiar,Zhijie Zhou,Hualin Zhao,Wenchao Lin,Xianci Zhong,Bingsuo Zou

Among a II–VI semiconductor, ZnTe is an inherent p-type semiconductor and exhibits strong emissions within the visible range, which make it suitable for various optoelectronic applications. Here, we have obtained the ZnTe- and Fe-doped ZnTe microbelt by CVD growth. Near-infrared (NIR) luminescence from 600 to 1000 nm can be seen in the PL emission spectra of ZnTe microstructure excited by CW laser, along with the appearance of multimode peaks because of the optical microcavity. The NIR luminescence in ZnTe comes from the presence of Zn vacancies due to polymorphous transition of ZnTe in the vapor solid mechanism. The PL emission under femtosecond pulsed laser excitation produces a low-threshold laser line which is near the band edge of the ZnTe microbelt, which is quite different from the continuous wave excitation PL spectrum. The time of photon–matter interaction and the fast and slow coherent recombination of exciton and defect states determine their emission distribution. As the excitation pulse changes, the different optical behaviors generated by the semiconductor may be applied in many photonic devices. We also found that in addition to the two sides of the microbelt that form the FP cavity in the pure ZnTe microbelt, the interface in the doped ZnTe microbelt can also form the FP cavity together with one side of the microbelt; the presence of interface is due to the presence of impurities.