The design of polymer acceptors plays an essential role in the performance of all‐polymer solar cells. Recently, the strategy of polymerized small molecules has achieved great success, but most polymers are synthesized from the mixed monomers, which seriously affects batch‐to‐batch reproducibility. Here, a method to separate γ‐Br‐IC or δ‐Br‐IC in gram scale and apply the strategy of monomer configurational control in which two isomeric polymeric acceptors (PBTIC‐γ‐2F2T and PBTIC‐δ‐2F2T) are produced is reported. As a comparison, PBTIC‐m‐2F2T from the mixed monomers is also synthesized. The γ‐position based polymer (PBTIC‐γ‐2F2T) shows good solubility and achieves the best power conversion efficiency of 14.34% with a high open‐circuit voltage of 0.95 V when blended with PM6, which is among the highest values recorded to date, while the δ‐position based isomer (PBTIC‐δ‐2F2T) is insoluble and cannot be processed after parallel polymerization. The mixed‐isomers based polymer, PBTIC‐m‐2F2T, shows better processing capability but has a low efficiency of 3.26%. Further investigation shows that precise control of configuration helps to improve the regularity of the polymer chain and reduce the π–π stacking distance. These results demonstrate that the configurational control affords a promising strategy to achieve high‐performance polymer acceptors.
A porous
two-dimensional (2D) metal–organic framework (MOF), namely,
[Cd(PBA)(DMF)]·DMF (Cd-PBA), has been solvothermally synthesized
by the reaction of 5-(4-pyridin-3-yl-benzoylamino)-isophthalic acid
ligand (H2PBA) and Cd(II) ions. Structural analysis shows
that Cd-PBA possesses 2D (3,6)-connected kgd net topology
with the Schläfli symbol of (43)2(46.66.83) and exhibits two distinct types
of one-dimensional opening channels along a- and c-axes. The incorporation of Cd metal centers and −NH
groups of amides endows Cd-PBA rich open metal sites and Lewis basic
sites, which are applied as an efficient catalyst for the important
Knoevenagel condensation and cyanosilylation of aldehyde reactions.
This Cd-PBA presents highly efficient catalytic activity and recyclability
for both Knoevenagel condensation reaction and cyanosilylation of
various aldehydes with trimethylsilyl cyanide (TMSCN). The excellent
catalytic activity can be maintained at least four cycles without
loss of obvious catalytic activity. These results indicate Cd-PBA
can serve as a promising heterogeneous catalyst toward C–C
bond formation due to the stability and high catalytic activity.
Oligomeric acceptors are expected to combine the advantages of both highly developed small molecular and polymeric acceptors. However, organic solar cells (OSCs) based on oligomers lag far behind due to their slow development and low diversity. Here, three oligomeric acceptors were produced through oligomerization of small molecules. The dimer dBTICγ‐EH achieved the best power conversion efficiencies (PCEs) of 14.48 % in bulk heterojunction devices and possessed a T80 (80 % of the initial PCE) lifetime of 1020 h under illumination, which were far better than that of small molecular and polymeric acceptors. More excitingly, it showed PCEs of 16.06 % in quasi‐planar heterojunction (Q‐PHJ) devices which is the highest value OSCs using oligomeric acceptors to date. These results suggest that oligomerization of small molecules is a promising strategy to achieve OSCs with optimized performance between the high efficiency and durable stability, and offer oligomeric materials a bright future in commercial applications.
Oligomeric acceptors are expected to combine the advantages of both highly developed small molecular and polymeric acceptors. However, organic solar cells (OSCs) based on oligomers lag far behind due to their slow development and low diversity. Here, three oligomeric acceptors were produced through oligomerization of small molecules. The dimer dBTICγ-EH achieved the best power conversion efficiencies (PCEs) of 14.48 % in bulk heterojunction devices and possessed a T80 (80 % of the initial PCE) lifetime of 1020 h under illumination, which were far better than that of small molecular and polymeric acceptors. More excitingly, it showed PCEs of 16.06 % in quasi-planar heterojunction (Q-PHJ) devices which is the highest value OSCs using oligomeric acceptors to date. These results suggest that oligomerization of small molecules is a promising strategy to achieve OSCs with optimized performance between the high efficiency and durable stability, and offer oligomeric materials a bright future in commercial applications.
Metal–organic
framework-derived lithium cobaltate nanoparticles
were fabricated by annealing of the ZIF-67 precursor with Li2CO3 under air, followed by homogeneous AlF3 coating and carbon nanotubes (CNTs) wrapping. The as-prepared AlF3-coated LiCoO2/CNTs electrode can act as a potential
cathode for enhanced lithium storage at both room temperature and
an elevated temperature of 50 °C.
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