Solution-Processed Short-Wave Infrared PbS Colloidal Quantum Dot/ZnO Nanowire Solar Cells Giving High Open-Circuit Voltage

A systematic investigation into the performance of PbS quantum dot (QD)/ZnO nanowire (NW) solar cells in the near-infrared (NIR) and short-wave infrared (SWIR) regions was carried out. The solar cells were confirmed to convert a wide range of solar energy (3.54–0.62 eV, corresponding to 0.35–2.0 μm). We found that the solar cells working in the SWIR region had a high open-circuit voltage (<i>V</i>_oc). A relatively high <i>V</i>_oc of 0.25 V was achieved even in solar cells whose photocurrent onsets were at approximately 0.64 eV (1.9 μm); this <i>V</i>_oc is as high as that of Ge solar cells, which have been used for III–V compound semiconductor triple-junction solar cells. Although short-circuit current density and fill factor have to be further increased, these results indicate that solution-processed colloidal QD solar cells with ZnO NWs are promising candidates for the middle and/or bottom subcells of multijunction solar cells

Interval Neutrosophic Sets and Logic: Theory and Applications in Computing

This book presents the advancements and applications of neutrosophics. Chapter 1 first introduces the interval neutrosophic sets which is an instance of neutrosophic sets. In this chapter, the definition of interval neutrosophic sets and set-theoretic operators are given and various properties of interval neutrosophic set are proved. Chapter 2 defines the interval neutrosophic logic based on interval neutrosophic sets including the syntax and semantics of first order interval neutrosophic propositional logic and first order interval neutrosophic predicate logic. <br

PbS-Quantum-Dot-Based Heterojunction Solar Cells Utilizing ZnO Nanowires for High External Quantum Efficiency in the Near-Infrared Region

The improvement of solar cell performance in the near-infrared (near-IR) region is an important challenge to increase power conversion efficiency under one-sun illumination. PbS quantum-dot (QD)-based heterojunction solar cells with high efficiency in the near-IR region were constructed by combining ZnO nanowire arrays with PbS QDs, which give a first exciton absorption band centering at wavelengths longer than 1 μm. The morphology of ZnO nanowire arrays was systematically investigated to achieve high light-harvesting efficiency as well as efficient carrier collection. The solar cells with the PbS QD/ZnO nanowire structures made up of densely grown thin ZnO nanowires about 1.2 μm long yielded a maximum incident-photon-to-current conversion efficiency (IPCE) of 58% in the near-IR region (@1020 nm) and over 80% in the visible region (shorter than 670 nm). The power conversion efficiency obtained on the solar cell reached about 6.0% under simulated one-sun illumination

Transporting Cells in Semi-Solid Gel Condition and at Ambient Temperature

<div><p>Mammalian cells including human cancer cells are usually transported in cryovials on dry ice or in a liquid nitrogen vapor shipping vessel between different places at long distance. The hazardous nature of dry ice and liquid nitrogen, and the associated high shipping cost strongly limit their routine use. In this study, we tested the viability and properties of cells after being preserved or shipped over long distance in Matrigel mixture for different days. Our results showed that cells mixed with Matrigel at suitable ratios maintained excellent viability (>90%) for one week at room temperature and preserved the properties such as morphology, drug sensitivity and metabolism well, which was comparable to cells cryopreserved in liquid nitrogen. We also sent cells in the Matrigel mixture via FedEx service to different places at ambient temperature. Upon arrival, it was found that over 90% of the cells were viable and grew well after replating. These data collectively suggested that our Matrigel-based method was highly convenient for shipping live cells for long distances in semi-solid gel condition and at ambient temperature.</p></div

Comparison of properties of cells recovered from medium supplemented Matrigel (MT) and thawed from cryopreserved vials in liquid nitrogen (LN).

<p>MCF-7 cells were preserved in medium (34%) supplemented Matrigel (66%) for 7 days, and were recovered as described in Materials and Methods. Cryopeserved cells in liquid nitrogen as <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0128229#pone.0128229.g002" target="_blank">Fig 2</a> was used as a control. (a) Growth of MCF-7 cells treated with hormone (estradiol, <i>E2</i>) or vehicle was assayed. (b) Glucose consumption and lactate production were detected as described in material and methods. (c) Cell growth was detected by MTT assay after cells treated with chemotherapy drug doxorubicin and taxol for 48 hours. The data are presented as the mean ± SD, **, <i>p <</i> 0.01; N.S., not significant.</p

The survival rate of various types of cells recovered from medium supplemented Matrigel and thawed from cryopreserved vials in liquid nitrogen.

<p>Various types of cells at 5×10⁶ per ml were cryopreserved in cryogenic vial in liquid nitrogen or stored in medium (34%) supplemented Matrigel (66%) at room temperature for 7 days, cells were then recovered for assays. (a) Cell survival rates were detected by Trypan blue exclusion assay. (b) Cell growth assay were done as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0128229#pone.0128229.g002" target="_blank">Fig 2(e)</a>. (c) and (d) Cell colony formation were determined as described in material and methods. The data are presented as the mean ± SD, *, <i>p <</i> 0.05; N.S., not significant.</p

A flowchart of the Matrigel based method for transporting cells in semi-solid gel condition and at ambient temperature.

<p>A flowchart of the Matrigel based method for transporting cells in semi-solid gel condition and at ambient temperature.</p

The survival rate of MCF-7 cells stored in the cell growth medium supplemented Matrigel.

<p>Cells were preserved in cryogenic vials in liquid nitrogen (LN) for 14 days, and were thawed and used as a control for determined cell viability by trypan blue exclusion assay. (a) Images of cells stored in medium supplemented Matrigel in Eppendorf tubes. (b) Cells were recovered from medium (34%) supplemented Matrigel (66%) as described in Materials and Methods, the cell survival rate was determined at the indicated time. (c) Cells were preserved in the mixture with different ratios between medium and Matrigel for 7 days, and were recovered for determining cell survival rate. (d) Different densities of cells were preserved in medium (34%) supplemented Matrigel (66%) for 7 days, and were recovered for determining cell survival rate. (e) and (f) Cells were preserved in medium (34%) supplemented Matrigel (66%) for 7 days, and were recovered for cell growth assay as described in Materials and Methods. Representative images showed cellular morphology. The data are presented as the mean ± SD *, <i>p <</i> 0.05; **, <i>p <</i> 0.01; n.s., not significant.</p