The ternary strategy has been widely identified as an effective approach to obtain high‐efficiency organic solar cells (OSCs). However, for most ternary OSCs, the nonradiative voltage loss lies ...between those of the two binary devices, which limits further efficiency improvements. Herein, an asymmetric guest acceptor BTP‐2F2Cl is designed and incorporated into a PM1:L8‐BO host blend. Compared with the L8‐BO neat film, the L8‐BO:BTP‐2F2Cl blend film shows higher photoluminescence quantum yield and larger exciton diffusion length. Introducing BTP‐2F2Cl into the host blend extends its absorption spectrum, improves the molecular packing of host materials, and suppresses the nonradiative charge recombination of the ternary OSCs. Consequently, the power conversion efficiency is improved up to 19.17% (certified value 18.7%), which represents the highest efficiency value reported for single‐junction OSCs so far. The results show that improving the exciton behaviors is a promising approach to reducing the nonradiative voltage loss and realizing high‐performance OSCs.
A new ternary system is developed by introducing an asymmetric electron acceptor BTP‐2F2Cl into the PM1:L8‐BO host system. The ternary system exhibits a record‐high efficiency of 19.17% and demonstrates better long‐term stability compared to the host system.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Gasdermin E (GSDME) has an important role in inducing secondary necrosis/pyroptosis. Upon apoptotic stimulation, it can be cleaved by activated caspase-3 to generate its N-terminal fragment ...(GSDME-NT), which executes pyroptosis by perforating the plasma membrane. GSDME is expressed in many human lung cancers including A549 cells. Paclitaxel and cisplatin are two representative chemotherapeutic agents for lung cancers, which induce apoptosis via different action mechanisms. However, it remains unclear whether they can induce GSDME-mediated secondary necrosis/pyroptosis in lung A549 cancer cells. Here we showed that both paclitaxel and cisplatin evidently induced apoptosis in A549 cells as revealed by the activation of multiple apoptotic markers. Notably, some of the dying cells displayed characteristic morphology of secondary necrosis/pyroptosis, by blowing large bubbles from the cellular membrane accompanied by caspase-3 activation and GSDME-NT generation. But the ability of cisplatin to induce this phenomenon was much stronger than that of paclitaxel. Consistent with this, cisplatin triggered much higher activation of caspase-3 and generation of GSDME-NT than paclitaxel, suggesting that the levels of secondary necrosis/pyroptosis correlated with the levels of active caspase-3 and GSDME-NT. Supporting this, caspase-3 specific inhibitor (Ac-DEVD-CHO) suppressed cisplatin-induced GSDME-NT generation and concurrently reduced the secondary necrosis/pyroptosis. Besides, GSDME knockdown significantly inhibited cisplatin- but not paclitaxel-induced secondary necrosis/pyroptosis. These results indicated that cisplatin induced higher levels of secondary necrosis/pyroptosis in A549 cells than paclitaxel, suggesting that cisplatin may provide additional advantages in the treatment of lung cancers with high levels of GSDME expression.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Despite the remarkable progress achieved in recent years, organic photovoltaics (OPVs) still need work to approach the delicate balance between efficiency, stability, and cost. Herein, two fully ...non‐fused electron acceptors, PTB4F and PTB4Cl, are developed via a two‐step synthesis from single aromatic units. The introduction of a two‐dimensional chain and halogenated terminals for these non‐fused acceptors plays a synergistic role in optimizing their solid stacking and orientation, thus promoting an elongated exciton lifetime and fast charge‐transfer rate in bulk heterojunction blends. As a result, PTB4Cl, upon blending with PBDB‐TF polymer, has enabled single‐junction OPVs with power conversion efficiencies of 12.76 %, representing the highest values among the reported fully unfused electron acceptors so far.
Two new non‐fused‐ring acceptors (NFRAs), denoted as PTB4F and PTB4Cl, are developed via a two‐step synthesis from simple phenyl and thiophene units. The corresponding organic photovoltaics based on PTB4Cl:PBDB‐TF have impressively achieved a power conversion efficiency of 12.76 %, representing the highest value among the fully non‐fused NFRAs reported so far.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Device engineering is an effective way to improve the photovoltaic performance of organic solar cells (OSCs). Currently, the widely used bulk heterojunction (BHJ) structure has problems such as ...material solubility limitations and the emerging pseudoplanar heterojunction (PPHJ) structure is also troubled by printing technology requirements. However, these issues can be solved by the reasonable application of traditional planar heterojunction (PHJ) structure. Herein, PM6:BO‐4F system is selected to prepare PHJ devices by combining sequential spin‐coating and orthogonal solvent strategy. In view of the good solubility of PM6 and BO‐4F in commonly used high‐boiling solvent chlorobenzene (CB) and green solvent tetrahydrofuran (THF), respectively, the PHJ devices are successfully prepared by using these two orthogonal solvents, achieving a power conversion efficiency (PCE) of 15.6%. On this basis, green nonhalogen reagent o‐xylene (O‐XY) is further used to process PM6. Due to the large polarity difference between O‐XY and THF, all‐green solvent‐processed PHJ devices are successfully fabricated and obtain an astonishing PCE of 16%. As far as it is known, it is the highest efficiency for PHJ OSCs. The results prove the huge research potential of PHJ structure and point out new direction for solving OSC materials compatibility, long‐term stability, and future commercial applications.
Device engineering is an effective way to improve the photovoltaic performance of organic solar cells. Herein, PM6:BO‐4F system is selected to prepare planar heterojunction (PHJ) devices. The PHJ devices are successfully fabricated by using green orthogonal solvents of o‐xylene (O‐XY) and tetrahydrofuran (THF), achieving an excellent power conversion efficiency (PCE) of 16%, which is the highest efficiency of the PHJ structure.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Nonfullerene acceptors (NFAs) are regarded as star candidates for efficient organic solar cells with power conversion efficiency (PCE) over 18%. In contrast to the rapid development of NFA materials, ...however, the underlying excited-state dynamics which fundamentally govern the device performance remains unclear. In this Perspective, we discuss recent advances and provide our insights on photoinduced charge transfer and combination dynamics in NFA-based organic solar cells (OSCs), including the biphasic hole-transfer process and its correlation with morphology, the role of driving force and Marcus normal region behavior on interfacial hole-transfer properties, and charge recombination energy loss by NFA triplet formation. We also discuss our understanding of how to control the charge-transfer and recombination processes by phase morphology and molecular design to improve OSC performance. Finally, we suggest a few research directions, including the interfacial charge transfer and separation mechanism, the origin of low fill factor, and complex excited-state dynamics in multicomponent OSCs.
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IJS, KILJ, NUK, PNG, UL, UM
Antimony trisulfide (Sb
S
) is considered to be a promising photovoltaic material; however, the performance is yet to be satisfactory. Poor power conversion efficiency and large open circuit voltage ...loss have been usually ascribed to interface and bulk extrinsic defects By performing a spectroscopy study on Sb
S
polycrystalline films and single crystal, we show commonly existed characteristics including redshifted photoluminescence with 0.6 eV Stokes shift, and a few picosecond carrier trapping without saturation at carrier density as high as approximately 10
cm
. These features, together with polarized trap emission from Sb
S
single crystal, strongly suggest that photoexcited carriers in Sb
S
are intrinsically self-trapped by lattice deformation, instead of by extrinsic defects. The proposed self-trapping explains spectroscopic results and rationalizes the large open circuit voltage loss and near-unity carrier collection efficiency in Sb
S
thin film solar cells. Self-trapping sets the upper limit on maximum open circuit voltage (approximately 0.8 V) and thus power conversion efficiency (approximately 16 %) for Sb
S
solar cells.
The ternary blend is demonstrated as an effective strategy to promote the device performance of organic photovoltaics (OPVs) due to the dilution effect. While the compromise between the charge ...generation and recombination remains a challenge. Here, a mixed diluent strategy for further improving the device efficiency of OPV is proposed. Specifically, the high‐performance OPV system with a polymer donor, i.e., PM6, and a nonfullerene acceptor (NFA), i.e., BTP‐eC9, is diluted by the mixed diluents, which involve a high bandgap NFA of BTP‐S17 and a low bandgap NFA of BTP‐S16 (similar with that of the BTP‐eC9). The BTP‐S17 of better miscibility with BTP‐eC9 can dramatically enhance the open‐circuit voltage (VOC), while the BTP‐S16 maximizes the charge generation or the short‐circuit current density (JSC). The interplay of BTP‐17 and BTP‐S16 enables better compromise between charge generation and recombination, thus leading to a high device performance of 19.76% (certified 19.41%), which is the best among single‐junction OPVs. Further analysis on carrier dynamics validates the efficacy of mixed diluents for balancing charge generation and recombination, which can be further attributed to the more diverse energetic landscapes and improved morphology. Therefore, this work provides an effective strategy for high‐performance OPV for further commercialization.
A mixed diluent strategy is proposed to better compromise the charge generation and recombination for multicomponent organic photovoltaics (MC‐OPVs), which involve a large bandgap and a low bandgap nonfullerene acceptors as diluent. This strategy improves balance between photocurrent and open‐circuit voltage, and enables a power conversion efficiency of 19.76% (certified 19.41%), which represents a world record of single‐junction OPV.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Enhancing the luminescence property without sacrificing the charge collection is one key to high-performance organic solar cells (OSCs), while limited by the severe non-radiative charge ...recombination. Here, we demonstrate efficient OSCs with high luminescence via the design and synthesis of an asymmetric non-fullerene acceptor, BO-5Cl. Blending BO-5Cl with the PM6 donor leads to a record-high electroluminescence external quantum efficiency of 0.1%, which results in a low non-radiative voltage loss of 0.178 eV and a power conversion efficiency (PCE) over 15%. Importantly, incorporating BO-5Cl as the third component into a widely-studied donor:acceptor (D:A) blend, PM6:BO-4Cl, allows device displaying a high certified PCE of 18.2%. Our joint experimental and theoretical studies unveil that more diverse D:A interfacial conformations formed by asymmetric acceptor induce optimized blend interfacial energetics, which contributes to the improved device performance via balancing charge generation and recombination.
With the deepening of the research on flipped classroom teaching theory, the flipped classroom teaching model has gradually been applied to classroom teaching at all levels and types of schools, and ...some beneficial results and experiences have been obtained. Due to the relatively low self-learning ability and motivation level of students, in the implementation of flipped classrooms, the quality of preclass self-study links is difficult to guarantee, resulting in unsatisfactory results of flipped classroom teaching in secondary vocational schools. This article aims to solve the current dilemma faced by the optimization of the flipped classroom teaching mode of programming courses by studying the course platform based on the flipped classroom teaching model. The source-destination node distribution is constructed with a model based on node affinity to restore the actual network node distribution architecture. The change in the distribution of source-destination nodes has led to different degrees of aggregation in the overall data flow of the network. After that, the capacity and delay performance of the primary network and the secondary network will change as the degree of data flow aggregation changes. By laying base stations in the main network, we reanalyzed the network. Through the comprehensive analysis of students’ learning status through the scores of students in class and the test situation after class, we modify the specific teaching plan of flipped classroom. Experiments have proved that the in-class flipping model we proposed effectively avoids the inherent shortcomings of students who are not strong in autonomous learning before class, solves the problem that secondary vocational students cannot do well in autonomous learning before class, and improves students to a certain extent. The results show that the flipped classroom teaching model in class can provide more powerful value for vocational teaching to achieve this goal.
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