38 research outputs found
In-Depth Consideration of Vertically 3D Microstructured Bulk Heterojunction Layers via Solvent Vapor Annealing in DR3TSBDT:PC<sub>71</sub>BM Solar Cells
The
physical nature of solvent vapor annealing (SVA) treatment
is quite straightforward, and its application is ideal in small molecule-based
bulk heterojunction solar cells. It has been suggested to rapidly
achieve high-performance small-molecule photovoltaics by alternating
the blends to ideally connect the crystallite morphology. However,
most previous reports on SVA have shown only influences of the degree
of donor/acceptor phase separation within part of active textures.
Here, we investigated solution-processed small-molecule solar cells
consisting of the previously developed DR3TSBDT and [6,6]-phenyl-C<sub>71</sub>-butyric acid methyl ester (PC<sub>71</sub>BM) after SVA
in terms of the vertical gradient crystalline phase in three-dimensional
(3D) active layers. These systematic studies of the vertically phase-separated
morphology for 3D heterojunction structures clarified in more detail
varied active blend morphology underlying SVA and showed a clear structure–property
relationship in related device performance. This provided not only
a clear understanding of the precise effect of SVA treatments on varied
3D morphological structures but also a path toward the rational optimization
of device performance
Schematic Studies on the Structural Properties and Device Physics of All Small Molecule Ternary Photovoltaic Cells
Although
the field of ternary organic solar cells has seen much progress in
terms of device performance in the past few years, limited understanding
has restricted further development. For example, studies of the crystalline
packing structure of ternary blends have rarely been reported in the
solar cell field. Consequently, we chose two ternary blends of small
molecules, two fullerene derivatives (small-molecule:PC<sub>71</sub>BM:PC<sub>61</sub>BM or small-molecule:PC<sub>71</sub>BM:ICBA), to
investigate crystallization behavior and interactions among the three
components. The crystalline structure of the ternary active blends
was characterized using various techniques such as 2D-GIWAXS and AFM,
and the relationship of the observed morphologies to device performance
is discussed. Furthermore, the device physics associated with the
charge generation, transport, and recombination dynamics of these
ternary blend systems were investigated
Structure–Property Correlation: A Comparison of Charge Carrier Kinetics and Recombination Dynamics in All-Polymer Solar Cells
We
report a comparison of charge carrier kinetics and recombination
dynamics correlated with the device performances of <b>PBDTTT-C</b> and <b>PBDTTT-CT</b> in nonfullerene <b>PÂ(NDI2OD-T2)</b> solar cells. The nanoscale morphological characteristics are found
to be remarkably different for these two polymers in all-polymer bulk
heterojunction (BHJ) blends. Important insights into the carrier dynamics
and crystalline packing features of these different donor materials
are provided in detail. The higher device performance of the <b>PBDTTT-CT:PÂ(NDI2OD-T2)</b> device [2.78% compared to 1.56% for
the <b>PBDTTT-C:PÂ(NDI2OD-T2)</b> cell] is shown to result from
efficient charge generation and faster carrier separation, reducing
nongeminate recombination during charge collection, which is attributed
to the perfect intermixing between the donor and acceptor polymer
networks
Tumor-specific mutation detection rates in groups classified according to the presence of distant metastasis at the time of blood sampling.
<p>Tumor-specific mutation detection rates in groups classified according to the presence of distant metastasis at the time of blood sampling.</p
Comparison of survival rates of patients in the metastasis group with or without detectable plasma tumor-specific <i>KRAS</i> mutations.
<p>Overall survival rates are poorer for patients with detectable plasma <i>KRAS</i> mutations than patients without detectable plasma <i>KRAS</i> mutations.</p
Box and whisker plots of concentrations of circulating DNA.
<p>The concentration of DNA was significantly higher in patient groups (metastasis and non-metastasis groups) than in healthy volunteers (<i>P</i><0.001). There was no significant difference between patient groups. (Horizontal line in the middle of each box, median; boxes, 25 percentile ~ 75 percentile; whiskers, 1.5 x interquartile range from each boundary of the boxes; circles, outlier values with corresponding case number; <i>P</i>-value by Mann-Whitney U test, two-tailed).</p
Comparison of clinicopathological features between patient subgroups with or without detectable plasma tumor-specific <i>KRAS</i> mutations within the metastasis group (n = 106).
<p>Comparison of clinicopathological features between patient subgroups with or without detectable plasma tumor-specific <i>KRAS</i> mutations within the metastasis group (n = 106).</p
Isolation of Coralmycins A and B, Potent Anti-Gram Negative Compounds from the Myxobacteria <i>Corallococcus coralloides</i> M23
Two new potent anti-Gram negative
compounds, coralmycins A (<b>1</b>) and B (<b>2</b>),
were isolated from cultures of the myxobacteria <i>Corallococcus
coralloides</i> M23, together with another derivative (<b>3</b>) that was identified as the very recently reported cystobactamid
919-2. Their structures including the relative stereochemistry were
elucidated by interpretation of spectroscopic, optical rotation, and
CD data. The relative stereochemistry of <b>3</b> was revised
to “<i>S*R*</i>” by NMR analysis. The antibacterial
activity of <b>1</b> was most potent against Gram-negative pathogens,
including <i>Escherichia coli</i>, <i>Pseudomonas aeruginosa</i>, <i>Acinetobacter baumanii</i>, and <i>Klebsiella
pneumoniae</i>, with MICs of 0.1–4 μg/mL; these
MICs were 4–10 and 40–100 times stronger than the antibacterial
activities of <b>3</b> and <b>2</b>, respectively. Thus,
these data indicated that the β-methoxyasparagine unit and the
hydroxy group of the benzoic acid unit were critical for antibacterial
activity
Efficient Encapsulation and Sustained Release of Basic Fibroblast Growth Factor in Nanofilm: Extension of the Feeding Cycle of Human Induced Pluripotent Stem Cell Culture
Basic fibroblast
growth factor (bFGF) has an established pivotal function in biomedical
engineering, especially for the human pluripotent stem cells (iPSCs).
However, the limitation of bFGF is the ease of denaturation under
normal physiological conditions, inducing loss of its activity. In
this study, we designed multi-trilayered nanofilm composed of a repeating
polycation/polyanion/bFGF structure, which has high loading efficiency
and short buildup time. We also investigated that the loading and
release of bFGF from the nanofilm with two parameters (counter-polyanion
and film architectures). Then, we prepared the optimized nanofilm
which maintains a sustained bFGF level in physiological condition
to apply the nanofilm to human iPSCs culture. The amount of bFGF release
from 12 trilayer nanofilm was 36.4 ng/cm<sup>2</sup>, and activity
of bFGF encapsulated into the nanofilm was maintained (60%) until
72 h during incubation at 37 °C. As a result, the iPSCs grown
in the presence of the nanofilm with tridaily replacement of growth
medium maintained undifferentiated morphology and expression levels
of pluripotency marker proteins
Dithienobenzodithiophene-Based Small Molecule Organic Solar Cells with over 7% Efficiency via Additive- and Thermal-Annealing-Free Processing
Here we introduce a novel small molecule
based on dithienobenzodithiophene
and rhodanine, <b>DTBDT-Rho</b>, developed to study the effect
of the rhodanine substitutuent on small molecule bulk heterojunction
(BHJ) solar cells. <b>DTBDT-Rho</b> possesses distinct crystalline
characteristics, sufficient solubility in chlorinated solvents, and
broad absorption properties. Therefore, solution-processed BHJ photovoltaic
cells made with <b>DTBDT-Rho</b>:PC<sub>71</sub>BM blends showed
an extremely high power conversion efficiency (PCE; 7.10%); notably,
this PCE value was obtained without the use of additives or thermal
treatments. To our knowledge, the PCE over 7% is a significantly powerful
value among rhodanine-based small molecule BHJ solar cells without
additives or thermal treatments