3 research outputs found
Impact of Precatalyst Activation on Suzuki-Miyaura Catalyst-Transfer Polymerizations: New Mechanistic Scenarios for Pre-transmetalation Events
The
relevance of L<sub>n</sub>PdX<sub>2</sub> precatalyst activation
on the Suzuki-Miyaura reaction course was investigated in the case
of catalyst-transfer polymerizations. A catalytic study, backed up
by theoretical calculations, allowed to ascertain the coexistence
of a neutral and an anionic mechanistic pathways in the precatalyst
activation, in which the bulky <sup><i>t</i></sup>Bu<sub>3</sub>P external ligand plays a crucial role. The fine-tuning of
the catalytic conditions can steer the activation step toward the
anionic pathway, leading to the full control over the polymerization
course. While providing insights and perspectives into the catalyst-transfer
polymerizations, these results uncover unexplored scenarios for the
pre-transmetalation events of Suzuki-Miyaura reactions contributing
to its full understanding
Sustainability of Organic Dye-Sensitized Solar Cells: The Role of Chemical Synthesis
The
synthesis of a novel and efficient π-extended D-A-π-A
organic sensitizer (<b>G3</b>, η = 8.64%) for dye-sensitized
solar cells has been accomplished by applying the green chemistry
pillars, aiming at overriding traditional routes involving organometallic
intermediates with innovative synthetic strategies for reducing the
waste burden and dye production costs. It has been demonstrated that
the obtainment of a complex target sensitizer can be exclusively pursued
via direct arylation reactions. Green metrics comparison with those
of a traditional synthetic pathway clearly indicates that the new
approach has a lower environmental impact in terms of chemical procedures
and generated wastes, stressing the importance of the synergy between
the molecular design and the synthetic plan in the framework of environmentally
friendly routes to back up sustainable development of third-generation
photovoltaics. Additionally, the stability of the <b>G3</b>-based
photovoltaic devices was also investigated in aging tests on large
area devices, evidencing the excellent potentialities of the proposed
structure for all practical applications involving inorganic semiconductor/organic
dye interfaces
Addressing the Function of Easily Synthesized Hole Transporters in Direct and Inverted Perovskite Solar Cells
Two
simple small molecules are designed and successfully implemented here
as hole-transporting material (HTM) in perovskite-based solar cells
(PSCs). With the aim of elucidating the interconnection between molecular
structure, properties, and their role in the working devices, these
HTMs are implemented in both thin planar direct (n–i–p)
and inverse (p–i–n) geometries. It is observed how the
HTM layer morphology influences the photovoltaic performance. Moreover,
from analysis of the different devices, fundamental information is
retrieved on the factors influencing small molecule hole extracting/transporting
functionality in PSCs. Specifically, two main roles are identified:
When HTMs are introduced as growing substrate (p–i–n),
there is a positive impact on the device performance via influence
of perovskite formation; meanwhile, their efficacy in transporting
the holes governs the performance of direct configurations (n–i–p).
These findings can be extended to a wide family of small molecule
HTMs, providing general rules for refining the design of novel and
more efficient ones