Unveiling the correlations among molecular structures, morphological characteristics, macroscopic properties and device performances is crucial for developing better photovoltaic materials and achieving higher efficiencies. To achieve this goal, a comprehensive study is performed based on four state-of-the-art non-fullerene acceptors (NFAs), which allows to systematically examine the above-mentioned correlations from different scales. It’s found that extending conjugation of NFA shows positive effects on charge separation promotion and non-radiative loss reduction, while asymmetric terminals can maximize benefits from both terminals. Another molecular optimization is from alkyl chain tuning. The shortened alkyl side chain results in strengthened terminal packing and decreased π-π distance, which contribute high carrier mobility and finally the high charge collection efficiency. With the most-acquired benefits from molecular structure and macroscopic factors, PM6:BTP-S9-based organic photovoltaics (OPVs) exhibit the optimal efficiency of 17.56% (certified: 17.4%) with a high fill factor of 78.44%, representing the best among asymmetric acceptor based OPVs. This work provides insight into the structure-performance relationships, and paves the way toward high-performance OPVs via molecular design.
The
donor/acceptor weight ratio is crucial for photovoltaic performance
of organic solar cells (OSCs). Here, we systematically investigate
the photovoltaic behaviors of PM6:Y6 solar cells with different stoichiometries.
It is found that the photovoltaic performance is tolerant to PM6 contents
ranging from 10 to 60 wt %. Especially an impressive efficiency over
10% has been achieved in dilute donor solar cells with 10 wt % PM6
enabled by efficient charge generation, electron/hole transport, slow
charge recombination, and field-insensitive extraction. This raises
the question about the origin of efficient hole transport in such
dilute donor structure. By investigating hole mobilities of PM6 diluted
in Y6 and insulators, we find that effective hole transport pathway
is mainly through PM6 phase in PM6:Y6 blends despite with low PM6
content. The results indicate that a low fraction of polymer donors
combines with near-infrared nonfullerene acceptors could achieve high
photovoltaic performance, which might be a candidate for semitransparent
windows.
This study investigated the interaction between eupatorin and bovine serum albumin (BSA) using ultraviolet-visible (UV-vis) absorption, fluorescence, synchronous fluorescence, circular dichroism (CD) spectroscopies, and molecular modeling at pH 7.4. Results of UV-vis and fluorescence spectroscopies illustrated that BSA fluorescence was quenched by eupatorin via a static quenching mechanism. Thermodynamic parameters revealed that hydrophobic and electrostatic interactions played major roles in the interaction. Moreover, the efficiency of energy transfer, and the distance between BSA and acceptor eupatorin, were calculated. The effects of eupatorin on the BSA conformation were analyzed using UV-vis, CD, and synchronous fluorescence. Finally, the binding of eupatorin to BSA was modeled using the molecular docking method.
Multi-component organic photovoltaics (OPVs), e.g., ternary blends, are effective for high performance, while the fundamental understanding from the molecular to device level is less-known. To address this issue, we here...
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