Structure and properties of a non-traditional glass containing TeO2, SeO2 and MoO3

Bachvarova-Nedelcheva, A.; Iordanova, R.; Kostov, Konstantin; Yordanov, St.; Ganev, Valentin

doi:10.1016/j.optmat.2012.05.002

Cited by 35 publications

(11 citation statements)

References 37 publications

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“…The new peaks at 575.6 and 585.9 eV were corresponding to the TeO 3 2– . Therefore, the Te 2– in QDs was also oxidized to TeO 3 2– by H 2 O 2 . , As shown in Figure S8, the fluorescence lifetime of QDs was nearly invariant before and after adding H 2 O 2 . The UV–vis absorption spectra, XPS, and fluorescence decay curves indicated that the mechanism of fluorescence quenching of QDs was in accord with that of static quenching.…”

Section: Resultsmentioning

confidence: 96%

One-Step Synthesis of Rox-DNA Functionalized CdZnTeS Quantum Dots for the Visual Detection of Hydrogen Peroxide and Blood Glucose

et al. 2017

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As the blood glucose concentration is an important clinical parameter of diabetes, the rapid and effective detection of blood glucose is very significant for monitoring and managing diabetes. Here, a facile method to prepare Rox-DNA functionalized CdZnTeS quantum dots (QDs) was developed. The Rox-DNA functionalized CdZnTeS QDs were prepared by a one-pot hydrothermal method through phosphorothioate DNA bound to QDs, which were employed as a ratiometric fluorescent probe for the rapid and sensitive detection of HO and glucose. Compared with the traditional multistep construction of ratiometric fluorescent probes, this presented approach is simpler and more effective without chemical modification and complicated separation. The CdZnTeS QDs with green fluorescence is specifically sensitive to HO, while the red fluorescence of Rox is invariable. HO is the product from the oxidation of glucose catalyzed by glucose oxidase (GOx). Therefore, a facile method to detect HO and glucose with a detection limit of 0.075 μM for HO and 0.042 μM for glucose was developed. In addition, this proposed probe has been employed for the detection of glucose in human serum with a satisfactory result. Moreover, this probe has been used for visual detection, and the health and diabetics can be distinguished by the naked eye. Meanwhile, this nanoprobe is also generalizable and can be extended to the detection of many other HO-mediated analytes.

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Section: Resultsmentioning

confidence: 96%

One-Step Synthesis of Rox-DNA Functionalized CdZnTeS Quantum Dots for the Visual Detection of Hydrogen Peroxide and Blood Glucose

et al. 2017

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“…The broad peak at around 59.2 eV is attributed to the oxidized Se species such as the SeO 2 impurity. 57 However, these peaks are observable in as-grown but not in HBr-treated MoSe 2 layers. It is known that HBr is able to remove the oxygen in SeO 2 through the formation of SeBr 4 .…”

Section: Resultsmentioning

confidence: 98%

Photoluminescence Enhancement and Structure Repairing of Monolayer MoSe₂by Hydrohalic Acid Treatment

Han

Lu³

et al. 2016

ACS Nano

193

167

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Atomically thin two-dimensional transition-metal dichalcogenides (TMDCs) have attracted much attention recently due to their unique electronic and optical properties for future optoelectronic devices. The chemical vapor deposition (CVD) method is able to generate TMDCs layers with a scalable size and a controllable thickness. However, the TMDC monolayers grown by CVD may incorporate structural defects, and it is fundamentally important to understand the relation between photoluminescence and structural defects. In this report, point defects (Se vacancies) and oxidized Se defects in CVD-grown MoSe2 monolayers are identified by transmission electron microscopy and X-ray photoelectron spectroscopy. These defects can significantly trap free charge carriers and localize excitons, leading to the smearing of free band-to-band exciton emission. Here, we report that the simple hydrohalic acid treatment (such as HBr) is able to efficiently suppress the trap-state emission and promote the neutral exciton and trion emission in defective MoSe2 monolayers through the p-doping process, where the overall photoluminescence intensity at room temperature can be enhanced by a factor of 30. We show that HBr treatment is able to activate distinctive trion and free exciton emissions even from highly defective MoSe2 layers. Our results suggest that the HBr treatment not only reduces the n-doping in MoSe2 but also reduces the structural defects. The results provide further insights of the control and tailoring the exciton emission from CVD-grown monolayer TMDCs.

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“…The signals for all three samples are fit with two individual peaks (at 529.2–529.3 and 531.6–531.8 eV), both of which are stronger in the CdCl 2 ‐treated sample. The lower energy peak is in the typical binding energy range for nonbridging metaloxide bonds, while the higher energy peak is in the range for bridging metal–oxygen–metal bonds . Further identification of the two (or more) environments is not possible since the chemical shifts are not sufficiently different to allow it.…”

Section: Resultsmentioning

confidence: 99%

“…Note that depth profi les were repeated on separate regions of all samples and this accumulation was again (and only) seen in the CdCl 2 -treated sample. [ 58,59 ] Further identifi cation of the two (or more) environments is not possible since the chemical shifts are not suffi ciently different to allow it. In this case, the O accumulation at the CdTe-CdS interface for the CdCl 2treated sample suggests that the out-diffusion mechanism into the CdTe is restricted.…”

Section: Chemical Analysis Of Cdte Surface and Device Stackmentioning

confidence: 99%

A Comparative Study of the Effects of Nontoxic Chloride Treatments on CdTe Solar Cell Microstructure and Stoichiometry

Williams

Major

Bowen

et al. 2015

Advanced Energy Materials

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either by vapor deposition [ 5,8,10,11 ] or by drop-casting of a CdCl 2 /methanol solution (also used for CdTe nanoparticle solar cells), [ 7,[12][13][14] followed by an air-anneal at temperatures of ≈370-450 °C. While CdTe (as well as CdS) is a highly stable compound and is insoluble in water, the use of water-soluble CdCl 2 in the industrial production of CdTe modules may pose an environmental risk. Recently however, a breakthrough study demonstrated the direct replacement of the toxic (and costly) CdCl 2 with the nontoxic and cheap alternative, MgCl 2 , with no detriment to device performance. [ 15 ] Subsequently, both ZnCl 2[ 16 ] and NH 4 Cl [ 17 ] have also been shown to be potentially suitable alternatives. Interestingly, the use of other salts including NaCl, MnCl 2 , KCl, and HCl was signifi cantly less successful in terms of producing high effi ciencies. [ 15 ] Importantly, these recent studies have reopened a critical parameter space within the fabrication process. In order to accelerate process development, fundamental material studies are now required to investigate the relative effectiveness of different chloride compounds in inducing the desired materials changes in a CdTe thin-fi lm device stack. Moreover, by correlating such studies with the respective device performances, further improvements are anticipated. Reports of desirable materials changes associated with CdCl 2 activation include: Recrystallization and grain growth of CdTe [18][19][20] and CdS [ 5,21 ] fi lms (for minimization of stress and to reduce the density of deleterious defects), p-type doping of CdTe, [ 2,6,8,15 ] S/Te interdiffusion, [ 22,23 ] and grain boundary passivation. [ 5,24 ] However, such reports are often contradictory in terms of identifying which of these is most beneficial in improving effi ciency. [ 25 ] In this work, CdTe solar cell stacks (i.e., CdTe/CdS/ZnO/ SnO 2 /glass) treated with CdCl 2 , MgCl 2 , NaCl, and NH 4 Cl were subjected to extensive X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM) studies, with the critical aim being to distinguish the reasons as to why CdCl 2 and MgCl 2 treatments can yield higher effi ciencies than NH 4 Cl and, in particular, NaCl. The device performances, reported elsewhere, [ 15,17 ] for each of these Cl treatments, as well as those following MnCl 2 -and KCl treatments, This work presents the fi rst systematic comparison of the effects of a range of chlorides (CdCl 2 , MgCl 2 , NaCl, and NH 4 Cl) on the microstructure and chemical composition of CdTe/CdS/ZnO/SnO 2 solar cells, providing valuable insight to the ubiquitous Cl-activation process. Using X-ray diffraction, it is shown that CdCl 2 induces the greatest extent of recrystallization (standard deviation of texture coeffi cients, σ , reduces from 0.93 for as-grown CdTe to 0.43) and minimizing stress (from 178 MPa for as-grown material to zero). MgCl 2 treatment also yields signifi cant randomization of the CdTe texture ( σ = 0.55) but NaCl treatment does not ( σ = 1....

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Structure and properties of a non-traditional glass containing TeO2, SeO2 and MoO3

Cited by 35 publications

References 37 publications

One-Step Synthesis of Rox-DNA Functionalized CdZnTeS Quantum Dots for the Visual Detection of Hydrogen Peroxide and Blood Glucose

One-Step Synthesis of Rox-DNA Functionalized CdZnTeS Quantum Dots for the Visual Detection of Hydrogen Peroxide and Blood Glucose

Photoluminescence Enhancement and Structure Repairing of Monolayer MoSe₂by Hydrohalic Acid Treatment

A Comparative Study of the Effects of Nontoxic Chloride Treatments on CdTe Solar Cell Microstructure and Stoichiometry

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Structure and properties of a non-traditional glass containing TeO2, SeO2 and MoO3

Cited by 35 publications

References 37 publications

One-Step Synthesis of Rox-DNA Functionalized CdZnTeS Quantum Dots for the Visual Detection of Hydrogen Peroxide and Blood Glucose

One-Step Synthesis of Rox-DNA Functionalized CdZnTeS Quantum Dots for the Visual Detection of Hydrogen Peroxide and Blood Glucose

Photoluminescence Enhancement and Structure Repairing of Monolayer MoSe2by Hydrohalic Acid Treatment

A Comparative Study of the Effects of Nontoxic Chloride Treatments on CdTe Solar Cell Microstructure and Stoichiometry

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Photoluminescence Enhancement and Structure Repairing of Monolayer MoSe₂by Hydrohalic Acid Treatment