Organic solar cells (OSCs) are regarded as one of the most promising flexible power sources due to their lightweight and flexible properties, with the improvement of photovoltaic and mechanical performance. To improve the current density and power conversion efficiency (PCE), mPh4F-TS (TS) and PYSe2F-T (PA) are introduced into the binary host, PM6/mPh4F-TT (PM6/TT) as third components. It is demonstrated that the corresponding ternary devices, in both rigid and flexible devices, achieved superior efficiencies (19.6%/17.7% for PM6/TT+TS, and 19.2%/17.4% for PM6/TT+PA) outperform the binary counterparts (18.3%/16.4%). However, distinct differences in mechanical performance are observed between the polymer acceptor (PA) and small-molecular acceptor (TS). The PM6/TT+PA significantly improved the mechanical stability of flexible devices with a lower elastic modulus of 3.6 GPa, while the PM6/TT+TS resulted in the opposite effect with a higher elastic modulus of 5.5 GPa. Through in-depth investigation, a clear correlation between the elastic modulus, crack density, and mechanical stability of the active layer blends is successfully established, revealing the key role of reducing the elastic modulus in enhancing the mechanical stability of flexible OSCs. This study provides important guidance for the development of flexible photovoltaic devices with both high efficiency and mechanical robustness.

Efficient charge transport and minimized energy loss are critical for advancing the performance of organic solar cells (OSCs). In this study, a series of quinoxaline-based electron acceptors, BQx-MeF, BQx-MeCl, and BQx-MeBr, featuring methyl and halogen substitutions is designed and synthesized to systematically modulate reorganization energy (λ) and film morphology. Quantum chemical calculations confirmed that methylation effectively reduces λ by limiting structural relaxation, leading to suppressed non-radiative recombination energy loss (ΔEnr) and improved charge transport. Among the synthesized materials, BQx-MeCl exhibited the lowest energy loss and the most balanced electron and hole mobilities, resulting in a superior power conversion efficiency (PCE) of 19.2% in a binary device. In optimized ternary OSCs, BQx-MeCl further reached a remarkable PCE of 19.6%. This enhancement is attributed to optimized molecular stacking, improved film morphology, and reduced trap-assisted recombination. These findings highlight the pivotal role of molecular design in lowering reorganization energy to minimize energy losses and maximize charge collection, offering an effective strategy for the development of high-efficiency OSCs.

Composite polymer electrolytes (CPE) have attracted considerable attention due to their potential to achieve high flexibility and large energy density. However, their practical application is hampered by their suitability at a single temperature and severe lithium dendrite growth. In this work, we have doped the perovskite inorganic filler LaCoO3 into polyamide (PI) nanofibers and constructed a LaCoO3/PI/PVDF CPE. Electrochemical characterization of the CPE and density functional theory calculations performed for it show that perovskite nanofibers have abundant oxygen vacancies, which are conducive to accelerating the dissociation of lithium salts and releasing more free lithium ions. Li//Li symmetric batteries exhibit excellent long cycle performance (over 3000 h) at 30 degrees C, and LiFePO4//Li batteries exhibit excellent cycling performance with over 1000 cycles at (0.5 C, 30 degrees C) and 400 cycles at (0.2 C, 60 degrees C), which can be realized with high voltage cathode NMC 811. The physical properties of the CPEs are also quite outstanding, with good thermal stability as it can withstand a high temperature of 200 degrees C and tensile strength up to 12.01 MPa. This work presents a new idea for designing CPEs with high safety and excellent electrochemical properties, which can provide stable circulation over a wide temperature range.

The difluoromethyl group is a crucial fluorinated moiety with distinctive biological properties, and the synthesis of chiral CF₂H-containing analogs has been recognized as a powerful strategy in drug design. To date, the most established method for accessing enantioenriched difluoromethyl compounds involves the enantioselective functionalization of nucleophilic and electrophilic CF₂H synthons. However, this approach is limited by lower reactivity and reduced enantioselectivity. Leveraging the unique fluorine effect, we design and synthesize a radical CF₂H synthon by incorporating isoindolinone into alkyl halides for asymmetric radical transformation. Here, we report an efficient strategy for the asymmetric construction of carbon stereocenters featuring a difluoromethyl group via nickel-catalyzed Negishi cross-coupling. This approach demonstrates mild reaction conditions and excellent enantioselectivity. Given that optically pure difluoromethylated amines and isoindolinones are key structural motifs in bioactive compounds, this strategy offers a practical solution for the efficient synthesis of CF₂H-containing chiral drug-like molecules. The difluoromethyl group is a crucial fluorinated moiety, and the synthesis of chiral CF₂H-containing analogs is a powerful strategy in drug design and screening. Here, the authors report a strategy for the asymmetric construction of carbon stereocenters featuring a difluoromethyl group via nickel-catalyzed Negishi cross-coupling.

Solid-state batteries (SSBs) with projected high safety and high-energy density have been heavily pursued as the next generation of electrochemical storage devices, while their realization still faces challenges, including scalable fabrication process, high-loading electrode, and robust thin solid electrolyte. Dry electrode technology (DET) is an emerging battery preparation method that embodies with numerous advantages, including simplified production procedures, loading-enhanced electrode, as well as elimination of solvent sensitivity. Currently, the DET is of great interest for its potential capability in upgrading the slurry-based SSB system that we are experiencing. Herein, the issues encountered in the wet process and the corresponding remedies by DET are introduced, followed by a summarization of multiple DET methodologies. The latest developments of DET are analyzed separately in terms of its application in cathode, anode, and solid electrolytes with emphasis on manufacturing method and material science. Binder selection, which has a growing influence on the quality of the dry film, is discussed as well. Based on the insights acquired, future potential attempts at DET are proposed to meet the goal of SSB commercialization.

The scaling strategy is widely used to achieve much improved performance and reduced cost in a single chip with more devices for field-effect transistors (FETs) based on Si and state-of-the-art 2D materials. However, the downscaling of polymer FETs with high performance has not been achieved. Here both the body thickness scaling and channel length scaling strategies are employed, and demonstrate a 2.4-nm-thick polymer monolayer FET, where the shortest channel length (L) of 18 nm is achieved that is comparable to the smallest technology node (≈20 nm) for planar Si FETs. Such short-channel FETs, with good operational stability and reliability, exhibit only slightly lower field-effect mobility than the device with micrometer-long channel, but the on-state current density reaches 2.4 × 10-4 A µm-1. More importantly, a high intrinsic gate delay of 0.79 ps is achieved, while maintaining the on/off current ratio up to 109. Additionally, by increasing the thickness of gate dielectric a remarkable short channel effect is observed, which is in excellent agreement with natural scale length evaluated by the Scale Length Theory.

Indoor organic photovoltaics (IOPVs) are an emerging LED light recycling technology with promising applications such as indoor off-grid ecosystem for the Internet of Things. However, efficient and stable IOPVs based on giant dimeric acceptors (GDAs) are rarely reported due to the dearth of GDAs with hypsochromic absorption (absorption onset < 850 nm) and good crystallinity. Herein, two hypsochromic GDAs are proposed with different fluorination degrees, namely DY4FO-V and DY6FO-V, and process a systematic study of hypsochromic acceptor materials from the small molecule to dimers and polymer. Interestingly, both hypsochromic GDAs possess better crystallinity, thus faster carrier transport and suppress recombination than small-molecule and polymer acceptor-based devices. With extra fluorination, PM6:DY6FO-V exhibits higher external quantum efficiency response and tighter packing compared with PM6:DY4FO-V. As a result, PM6:DY6FO-V delivers a champion efficiency over 29% under a LED illumination of 2000 lux (2600 k), positioning it the highest values for GDA-based IOPVs. Meanwhile, the high glass transition temperature of DY6FO-V endowed corresponding devices with great photostability and enhanced mechanical stability in flexible devices, demonstrating the feasibility of practical applications of the DY6FO-V-based IOPVs. This research underscores the huge potential of developing hypsochromic GDAs for highly efficient IOPVs with superior stability.

The rational design of non-fullerene acceptors (NFAs) with both high crystallinity and photoluminescence quantum yield (PLQY) is of crucial importance for achieving high-efficiency and low-energy-loss organic solar cells (OSCs). However, increasing the crystallinity of an NFA tends to decrease its PLQY, which results in a high non-radiative energy loss in OSCs. Here we demonstrate that the crystallinity and PLQY of NFAs can be fine-tuned by asymmetrically adapting the branching position of alkyl chains on the thiophene unit of the L8-BO acceptor. It was found that L8-BO-C4, with 2-butyloctyl on one side and 4-butyldecyl on the other side, can simultaneously achieve high crystallinity and PLQY. A high efficiency of 20.42

In the pursuit of advancing the commercialization of organic solar cells (OSCs), stability emerges as a paramount challenge. Herein, we show that the electron transport connectivity is a key factor determining the electron transport and device stability of OSCs. When compared to small molecular acceptors (SMAs), the larger-size polymeric acceptors (PAs) are likely to establish an electron transport network with superior connectivity. This enhanced connectivity enables more robust electron transport during potential device degradation. Our findings indicate that PA-integrated devices sustain elevated electron mobilities, even under reduced acceptor ratios (or higher impurity doping) over prolonged device operation. Furthermore, we employ the refined Su-Schrieffer-Heeger tight-binding model, in tandem with a random electron passing test and algebraic connectivity evaluations of molecular configurations, to conclusively validate the pivotal role played by the electron transport connectivity. These revelations are poised to offer new perspectives for material choices and methodologies for improving stability of OSCs.

Tuning the electronic properties of polymers is of great importance in designing highly efficient organic solar cells. Noncovalent intramolecular interactions have been often used as conformational control to enhance the planarity of polymers or molecules, which may reduce band gaps and promote charge transfer. However, it is little known if noncovalent interactions may alter the electronic properties of conjugated polymers through some mechanism other than the conformational control. Here, we studied the effects of various noncovalent interactions, including sulfur-nitrogen, sulfur-oxygen, sulfur-fluorine, oxygen-nitrogen, oxygen-fluorine, and nitrogen-fluorine, on the elec- tronic properties of polymers with planar geometry using unconstrained and constrained density functional theory. We found that the sulfur-nitrogen intramolecular interaction may reduce the band gaps of polymers and enhance the charge transfer more obviously than other noncovalent interactions. Our findings are also consistent with the experi- mental data. For the first time, our study shows that the sulfur-nitrogen noncovalent interaction may further affect the electronic structure of coplanar conjugated polymers, which cannot be only explained by the enhancement of molecular planarity. Our work suggests a new mechanism to manipulate the electronic properties of polymers to design high-performance small-molecule-polymer and all-polymer solar cells.

Side chain engineering of small-molecule ac-ceptors(SMAs)is a promising strategy for improving device efficiency in organic solar cells(OSCs).This study investigates the parent SMAs of BT-BO and BT-TBO,along with the newly synthesized asymmetric SMA,BT-ASY,which features bran-ched alkyl chains and thiophene side chains substituted at theβ positions of the thiophene units,respectively.Despite ex-hibiting comparable optical and electrochemical properties,the PM6:BT-ASY-based device achieves a power conversion efficiency(PCE)of 18.08％ representing a significant im-provement over its symmetric counterparts.This enhance-ment is primarily attributed to improved charge mobility,extended carrier lifetimes,optimized molecular packing,and effective phase separation,as confirmed by grazing incidence wide-angle X-ray scattering measurements.Our findings highlight that asymmetric side-chain strategy enhances π-πstacking and electronic coupling,offering a simple yet effective approach to improving photovoltaic performance.This work underscores the potential of asymmetric structural modifica-tions in SMAs for advancing OSC technology and renewable energy solutions.

Giant dimeric acceptors (GDAs), a sub-type of acceptor materials for organic solar cells (OSCs), have garnered much attention due to the synergistic advantages of their monomeric and polymeric acceptors, forming a well-defined molecular structure with a giant molecular weight for high efficiency and stability. In this study, for the first time, two new GDAs, DYF-V and DY2F-V are designed and synthesized for OSC operation, by connecting one vinylene linker with the mono-/di-fluorinated end group on two Y-series monomers, respectively. After fluorination, both DYF-V and DY2F-V exhibit bathochromic absorption and denser packing modes due to the stronger intramolecular charge transfer effect and torsion-free backbones. Through precise fluorination, the DYF-V-based devices exhibit the highest performance of 18.63% among the GDA-based OSCs, outperforming its non-fluorinated counterpart, DY-V-based ones (16.53%). Theoretical and morphological results demonstrate that proper fluorination in DYF-V-based devices strengthens intra/intermolecular interactions for enhanced crystallinity, superior phase segregation, and less energy disorder, which is beneficial for fast exciton dissociation, rapid carrier transport, and suppressed charge recombination. The work demonstrates that proper fluorination on GDAs with rigid coplanar backbones is effective for broader photon harvesting, stronger packing, and robust stability in GDA-based OSCs.

All perovskite tandem solar cells (PTSCs) were expected to overcome the Shockley-Queisser limit of single-junction perovskite solar cells (PSCs). Nevertheless, wide bandgap (WBG) subcells suffer from large photovoltage loss and device instability due to extensive film defect, interfacial degradation and phase segregation. Herein, a polymeric multi-dentate anchoring (PMDA) strategy by introducing poly(carbazole phosphonic acid) was employed to engineer the bottom interface and suppress phase segregation. The reinforced and homogeneous anchorage by multiple repeat phosphonic acid groups onto NiOx significantly optimised the bottom interface, suppressing unfavourable interfacial reactions and thus alleviating phase segregation of WBG perovskite. As a result, the PMDA-modified WBG PSCs showed higher power conversion efficiency (PCE) than the control device (19.84% vs. 18.18%), along with better device photostability (T80 = 1200 vs. 500 h). Coupled with narrow bandgap (NBG) PSCs, the PMDA-modified PTSCs reached a PCE of up to 28.51% with device operation photostability over 700 h (T80).

Ternary strategies have critical roles in pursuing high efficiencies for organic solar cells (OSCs).

A comparative investigation of electronic and transport properties of Te single atomic chain and Te single atomic chain encapsulated in carbon and boron nitride nanotubes (Te@CNT and Te@BNNT) based on first principle calculations. It is found Te@CNT and Te@BNNT show, respectively, type-II and type-I nanostructures with direct bandgap, and the band alignment relates to the diameter of NTs, whereas Te single atomic chain shows the transition between indirect and direct with compressive strain. Moreover, acoustic deformation potential (ADP) and ionized impurity (IMP) scattering rate play primarily responsible for the reduction of transport properties of Te single atomic chain and Te@NTs. The existence of NT can provide favorable surroundings to passivate dangling bonds and weak surface states for achieving high transport properties, and Te@CNT has the highest mobility due to the optimization of electronic and transport properties by CNT. Our results provide a guideline for designing high performance of 1D nanostructure for desirable applications.

Perovskite-based tandem solar cells (PTSCs) are promising for achieving higher efficiency limits, making them promising candidates for energy supply. However, the commercialization in complex scenarios necessitate extreme stability and reliability of tandem devices, particularly in ambient conditions. Herein, the use of a high-efficiency and air-stable quaternary all-polymer bulk heterojunction (BHJ) is pioneered to optimize spectral absorption, facilitate charge transport, and suppress exciton recombination, resulting in 18.0% of power conversion efficiency (PCE) in the organic subcell. The resultant monolithic perovskite/organic tandem solar cell (POTSC) delivers an impressive PCE of 24.8%, with minimal efficiency distribution and negligible hysteresis. Ambient stability tests on tandem devices reveal outstanding ambient stability, which is attributed to the reduced increase in exciton recombination. Remarkably, the unencapsulated tandem device maintained 88% of its initial efficiency after exposure to air for 500 h. The superior stability is owing to the enhanced resistance of the hydrophobic all-polymer BHJ to water and oxygen, thereby protecting the perovskite active layer. This work provides a novel approach from an organic perspective for achieving superior efficiency and stability in POTSC devices and holds promise for future real-world applications in the field of tandem solar cells.

The incorporation of thick active layers (>300 nm) is an essential requirement for wide-scale industrial production of organic solar cells (OSCs). However, it is still challenging to achieve efficient thick film devices, in particular for all-polymer OSCs, which are generally considered the most stable type of OSCs. In this study, a simple yet effective method is introduced by using a direct current (DC) field to manipulate the morphology of bulk heterojunction (BHJ) films within all-polymer OSCs during a blade coating process. By utilizing this method, a favorable vertical phase distribution is achieved, thereby effectively reducing the electron percolation threshold and enhancing the overall device performance. With this, an outstanding efficiency of 17.59% is achieved for thick-film all-polymer devices by blade-coating, which is the best performance in this category. This study introduces a non-contact DC field method aimed at mitigating the fabrication challenges encountered when transitioning thick-film all-polymer systems from laboratory to manufacturing settings, and will potentially contributing to the advancement of the OSC industrialization.

Boosting power conversion efficiency (PCE) of organic solar cells (OSCs) has been restricted by its undesirably high energy loss, especially for those nonhalogenated solvent-processed ones. Here,a dichloro-methoxylated terminal group in an asymmetric small molecular acceptor design, which realizes a significantly reduced non-radiative energy loss (0.179 eV) compared to its symmetric counterpart (0.202 eV), is reported. Consequently, the device efficiency is improved by up to 20% for PM6:BTP-eC9-4ClO, without sacrificing the photon harvest or charge transport ability of the control system PM6:BTP-eC9. Further characterizations reveal the asymmetric acceptor BTP-eC9-4ClO's blend film demonstrates a suppressed triplet state formation, enabled by an enhanced electron delocalization. In addition, the asymmetric BTP-eC9-4ClO is found to be thermally stabler than BTP-eC9, and thus providing an improved device stability, whose T80 value reaches > 7800 h under 80 °C anneal in N2 via linear extrapolation. This work represents state-of-the-art device performance for nonhalogenated solvent-processed binary OSCs with certified results (19.45%).

Alkoxylated dimeric giant acceptor DYO-V boosts organic solar cell efficiency and stability, achieving 20.2% PCE outdoors and 28.1% indoors, offering a versatile strategy for durable, high-performance photovoltaics.