3 research outputs found
[1]Benzothieno[3,2‑<i>b</i>]benzothiophene-Based Organic Dyes for Dye‑Sensitized Solar Cells
Three new metal-free organic dyes with the [1]ÂbenzothienoÂ[3,2-<i>b</i>]Âbenzothiophene (BTBT) Ď€-bridge, having the structure
donor-Ď€-acceptor (D-Ď€<i>-</i>A) and labeled
as <b>19</b>, <b>20</b> and <b>21</b>, have been
designed and synthesized for application in dye-sensitized solar cells
(DSSC). Once the design of the π-acceptor block was fixed, containing
the BTBT as the π-bridge and the cyanoacrylic group as the electron
acceptor and anchoring unit, we selected three donor units with different
electron-donor capacity, in order to assemble new chromophores with
high molar extinction coefficients (ε), whose absorption features
well reflect the good performance of the final DSSC devices. Starting
with the <b>19</b> dye, which shows a molar extinction coefficient
ε of over 14,000 M<sup>–1</sup> cm<sup>–1</sup> and takes into account the absorption maximun at the longer wavelength,
the substitution of the BFT donor unit with the BFA yields a great
enhancement of absorptivity (molar extinction coefficient ε
> 42,000 M<sup>–1</sup> cm<sup>–1</sup>), until reaching
the higher value (ε > 69,000 M<sup>–1</sup> cm<sup>–1</sup>) with the BFPhz donor unit. The good general photovoltaic
performances
obtained with the three dyes highlight the suitable properties of
electron-transport of the BTBT as the π-bridge in organic chromophore
for DSSC, making this very cheap and easy to synthesize molecule particularly
attractive for efficient and low-cost photovoltaic devices
Synthesis and Structure of Conjugated Molecules with the Benzofulvene Core
A general method
to synthesize conjugated molecules with a benzofulvene
core is reported. Up to four conjugated substituents have been introduced
via a three-step sequence including (1) synthesis of 1,2-bisÂ(arylethynyl)Âbenzenes;
(2) exo-dig electrophilic cyclization promoted by iodine; and (3)
cross-coupling reaction of the resulting bis-iodobenzofulvenes with
organoboron, organotin, or ethynyl derivatives under Pd catalysis.
Structural aspects of the new compounds are discussed
A Bioinformatics 3D Cellular Morphotyping Strategy for Assessing Biomaterial Scaffold Niches
Many
biomaterial scaffolds have been advanced to provide synthetic
cell niches for tissue engineering and drug screening applications;
however, current methods for comparing scaffold niches focus on cell
functional outcomes or attempt to normalize materials properties between
different scaffold formats. We demonstrate a three-dimensional (3D)
cellular morphotyping strategy for comparing biomaterial scaffold
cell niches between different biomaterial scaffold formats. Primary
human bone marrow stromal cells (hBMSCs) were cultured on 8 different
biomaterial scaffolds, including fibrous scaffolds, hydrogels, and
porous sponges, in 10 treatment groups to compare a variety of biomaterial
scaffolds and cell morphologies. A bioinformatics approach was used
to determine the 3D cellular morphotype for each treatment group by
using 82 shape metrics to analyze approximately 1000 cells. We found
that hBMSCs cultured on planar substrates yielded planar cell morphotypes,
while those cultured in 3D scaffolds had elongated or equiaxial cellular
morphotypes with greater height. Multivariate analysis was effective
at distinguishing mean shapes of cells in flat substrates from cells
in scaffolds, as was the metric L<sub>1</sub>-depth (the cell height
along its shortest axis after aligning cells with a characteristic
ellipsoid). The 3D cellular morphotyping technique enables direct
comparison of cellular microenvironments between widely different
types of scaffolds and design of scaffolds based on cell structure–function
relationships