Energy-efficient superparamagnetic Ising machine and its application to traveling salesman problems.

The growth of artificial intelligence leads to a computational burden in solving non-deterministic polynomial-time (NP)-hard problems. The Ising computer, which aims to solve NP-hard problems faces challenges such as high power consumption and limited scalability. Here, we experimentally present an Ising annealing computer based on 80 superparamagnetic tunnel junctions (SMTJs) with all-to-all connections, which solves a 70-city traveling salesman problem (TSP, 4761-node Ising problem). By taking advantage of the intrinsic randomness of SMTJs, implementing global annealing scheme, and using efficient algorithm, our SMTJ-based Ising annealer outperforms other Ising schemes in terms of power consumption and energy efficiency. Additionally, our approach provides a promising way to solve complex problems with limited hardware resources. Moreover, we propose a cross-bar array architecture for scalable integration using conventional magnetic random-access memories. Our results demonstrate that the SMTJ-based Ising computer with high energy efficiency, speed, and scalability is a strong candidate for future unconventional computing schemes.

Balancing Flexible Side Chains on 2D Conjugated Acceptors Enables High-Performance Organic Solar Cell.

Balancing the rigid backbones and flexible side chains of light-harvesting materials is crucially important to reach optimized intermolecular packing, micromorphology, and thus photovoltaic performance of organic solar cells (OSCs). Herein, based on a distinctive CH-series acceptor platform with 2D conjugation extended backbones, a series of nonfullerene acceptors (CH-6F-Cn) are synthesized by delicately tuning the lengths of flexible side chains from n-octyl to n-amyl. A systemic investigation has revealed that the variation of the side chain's length can not only modulate intermolecular packing modes and crystallinity but also dramatically improve the micromorphology of the active layer and eventual photovoltaic parameters of OSCs. Consequently, the highest PCE of 18.73% can be achieved by OSCs employing D18:PM6:CH-6F-C8 as light-harvesting materials.

What is the Limit Size of 2D Conjugated Extension on Central Units of Small Molecular Acceptors in Organic Solar Cells?

2D conjugated extension on central units of small molecular acceptors (SMAs) has gained great successes in reaching the state-of-the-art organic photovoltaics. Whereas the limit size of 2D central planes and their dominant role in constructing 3D intermolecular packing networks are still elusive. Thus, by exploring a series of SMAs with gradually enlarged central planes, it is demonstrated that, at both single molecular and aggerated levels, there is an unexpected blue-shift for their film absorption but preferable reorganization energies, exciton lifetimes and binding energies with central planes enlarging, especially when comparing to their Y6 counterpart. More importantly, the significance of well-balanced molecular packing modes involving both central and end units is first disclosed through a systematic single crystal analysis, indicating that when the ratio of central planes area/end terminals area is no more than 3 likely provides a preferred 3D intermolecular packing network of SMAs. By exploring the limit size of 2D central planes, This work indicates that the structural profiles of ideal SMAs may require suitable central unit size together with proper heteroatom replacement instead of directly overextending 2D central planes to the maximum. These results will likely provide some guidelines for future better molecular design.

High-speed flexible near-infrared organic photodiode for optical communication.

Optical communication is a particularly compelling technology for tackling the speed and capacity bottlenecks in data communication in modern society. Currently, the silicon photodetector plays a dominant role in high-speed optical communication across the visible-near-infrared spectrum. However, its intrinsic rigid structure, high working bias and low responsivity essentially limit its application in next-generation flexible optoelectronic devices. Herein, we report a narrow-bandgap non-fullerene acceptor (NFA) with a remarkable π-extension in the direction of both central and end units (CH17) with respect to the Y6 series, which demonstrates a more effective and compact 3D molecular packing, leading to lower trap states and energetic disorders in the photoactive film. Consequently, the optimized solution-processed organic photodetector (OPD) with CH17 exhibits a remarkable response time of 91 ns (λ = 880 nm) due to the high charge mobility and low parasitic capacitance, exceeding the values of most commercial Si photodiodes and all NFA-based OPDs operating in self-powered mode. More significantly, the flexible OPD exhibits negligible performance attenuation (<1%) after bending for 500 cycles, and maintains 96% of its initial performance even after 550 h of indoor exposure. Furthermore, the high-speed OPD demonstrates a high data transmission rate of 80 MHz with a bit error rate of 3.5 [Formula: see text] 10-4, meaning it has great potential in next-generation high-speed flexible optical communication systems.

Emerging Light-Harvesting Materials Based on Organic Photovoltaic D/A Heterojunctions for Efficient Photocatalytic Water Splitting.

Photocatalytic water splitting to hydrogen is a highly promising method to meet the surging energy consumption globally through the environmentally friendly means. As the initial step before photocatalysis, harvesting photons from sunlight is crucially important, thus making the design of photosensitizers with visible even near-infrared (NIR) absorptions get more and more attentions. In the past three years, organic donor/acceptor (D/A) heterojunctions with absorptions extending to 950 nm, have emerged as the new star light-harvesting materials for photocatalytic water splitting, demonstrating exciting advantages over inorganic materials in solar light utilization, hydrogen yielding rate, etc. This Minireview firstly gives a brief discussion about the principle processes and determining factors for photocatalytic water splitting with organic photovoltaic D/A heterojunction as photosensitizers. Thereafter, the current progress is summarized in details by introducing typical and excellent D/A heterojunction-based photocatalytic systems. Finally, not only the great prospects but also the most challenging issues confronted by organic D/A heterojunctions are indicated along with a perspective on the opportunities and new directions for future material explorations.

Central unit hetero-di-halogenation of acceptors enables organic solar cells with 19% efficiency.

Although peripheral hetero-di-halogenation of non-fullerene acceptors (NFAs) would allow more precise optimization of molecular properties by providing the complementary advantages of two different halogens, thus enabling further improvements of organic solar cells (OSCs), hetero-di-halogenated NFAs are seldom prepared due to the challenging construction of building blocks with two adjacent hetero-halogens. Herein, three CH-series acceptors with hetero-di-halogenated central units, named CH-FC, CH-FB and CH-CB, are constructed successfully. PM6:D18:CH-FB-based OSCs afforded an attractive PCE of 19.0% due to tighter intermolecular packing at both the single-crystal and blended-film levels, more efficient charge transfer/dissociation, and superior film morphology compared to those of PM6:D18:CH-FC (PCE 18.41%) and PM6:D18:CH-CB (PCE 18.21%). Our work highlights the effectiveness of such a CH-series molecular platform in conducting hetero-di-halogenation and achieving high-performance OSCs, and will stimulate further exploration of hetero-substitution-based acceptors.

Propeller vs Quasi-Planar 6-Cantilever Small Molecular Platforms with Extremely Two-Dimensional Conjugated Extension.

Two exotic 6-cantilever small molecular platforms, characteristic of quite different molecular configurations of propeller and quasi-plane, are established by extremely two-dimensional conjugated extension. When applied in small molecular acceptors, the only two cases of CH25 and CH26 that could contain six terminals and such broad conjugated backbones have been afforded thus far, rendering featured absorptions, small reorganization and exciton binding energies. Moreover, their distinctive but completely different molecular geometries result in sharply contrasting nanoscale film morphologies. Finally, CH26 contributes to the best device efficiency of 15.41 % among acceptors with six terminals, demonstrating two pioneered yet highly promising 6-cantilever molecular innovation platforms.

A Polymer Acceptor with Grafted Small Molecule Acceptor Unit for Efficient All Polymer Organic Solar Cells.

A polymer acceptor, named PX-1, is  designed and synthesized using a polymerization strategy with grafted small molecule acceptors. This design approach allows for the freedom of end groups while maintaining efficient terminal packing, enhancing π-π interactions, and facilitating charge transport. All-polymer organic solar cells based on PM6: PX-1 demonstrate a promising efficiency of 13.55%. The result presents an alternative pathway for the design of high-efficiency polymer acceptors through the careful regulation of small molecule acceptor monomers and linker units.

Complete Peripheral Fluorination of the Small-Molecule Acceptor in Organic Solar Cells Yields Efficiency over 19 .

Due to the intrinsically flexible molecular skeletons and loose aggregations, organic semiconductors, like small molecular acceptors (SMAs) in organic solar cells (OSCs), greatly suffer from larger structural/packing disorders and weaker intermolecular interactions comparing to their inorganic counterparts, further leading to hindered exciton diffusion/dissociation and charge carrier migration in resulting OSCs. To overcome this challenge, complete peripheral fluorination was performed on basis of a two-dimensional (2D) conjugation extended molecular platform of CH-series SMAs, rendering an acceptor of CH8F with eight fluorine atoms surrounding the molecular backbone. Benefitting from the broad 2D backbone, more importantly, strengthened fluorine-induced secondary interactions, CH8F and its D18 blends afford much enhanced and more ordered molecular packings accompanying with enlarged dielectric constants, reduced exciton binding energies and more obvious fibrillary networks comparing to CH6F controls. Consequently, D18:CH8F-based OSCs reached an excellent efficiency of 18.80 %, much better than that of 17.91 % for CH6F-based ones. More excitingly, by employing D18-Cl that possesses a highly similar structure to D18 as a third component, the highest efficiency of 19.28 % for CH-series SMAs-based OSCs has been achieved so far. Our work demonstrates the dramatical structural multiformity of CH-series SMAs, meanwhile, their high potential for constructing record-breaking OSCs through peripheral fine-tuning.

Terminally Chlorinated and Thiophene-linked Acceptor-Donor-Acceptor Structured 3D Acceptors with Versatile Processability for High-efficiency Organic Solar Cells.

To exploit the potential of our newly developed three-dimensional (3D) dimerized acceptors, a series of chlorinated 3D acceptors (namely CH8-3/4/5) were reported by precisely tuning the position of chlorine (Cl) atom. The introduction of Cl atom in central unit affects the molecular conformation. Whereas, by replacing fluorinated terminal groups (CH8-3) with chlorinated terminal groups (CH8-4 and CH8-5), the red-shift absorption and enhanced crystallization are achieved. Benefiting from these, all devices received promising power conversion efficiencies (PCEs) over 16 % as well as decent thermal/photo-stabilities. Among them, PM6:CH8-4 based device yielded a best PCE of 17.58 %. Besides, the 3D merits with multi alkyl chains enable their versatile processability during the device preparation. Impressive PCEs of 17.27 % and 16.23 % could be achieved for non-halogen solvent processable devices prepared in glovebox and ambient, respectively. 2.88 cm2 modules also obtained PCEs over 13 % via spin-coating and blade-coating methods, respectively. These results are among the best performance of dimerized acceptors. The decent performance of CH8-4 on small-area devices, modules and non-halogen solvent-processed devices highlights the versatile processing capability of our 3D acceptors, as well as their potential applications in the future.

Extending Se substitution to the limit: from 5S to 5Se in high-efficiency non-fullerene acceptors.

Based on the newly synthesized seleno[3,2-b]selenophene unit, two near-infrared non-fullerene acceptors (NFAs) of 4Se and 5Se are constructed by replacing four or all sulfurs with selenium in high-efficiency Y-series NFAs. Consequently, binary devices based on 4Se and 5Se afford PCEs of 15.17% and 15.23%, respectively, with a photoelectric response approaching 1000 nm. More excitingly, the energy loss of the 5Se-based device was as low as 0.477 eV along with almost the smallest non-radiative loss of ∼0.15 eV thus far.

A rare case of brominated small molecule acceptors for high-efficiency organic solar cells.

Given that bromine possesses similar properties but extra merits of easily synthesizing and polarizing comparing to homomorphic fluorine and chlorine, it is quite surprising very rare high-performance brominated small molecule acceptors have been reported. This may be caused by undesirable film morphologies stemming from relatively larger steric hindrance and excessive crystallinity of bromides. To maximize the advantages of bromides while circumventing weaknesses, three acceptors (CH20, CH21 and CH22) are constructed with stepwise brominating on central units rather than conventional end groups, thus enhancing intermolecular packing, crystallinity and dielectric constant of them without damaging the favorable intermolecular packing through end groups. Consequently, PM6:CH22-based binary organic solar cells render the highest efficiency of 19.06% for brominated acceptors, more excitingly, a record-breaking efficiency of 15.70% when further thickening active layers to ~500 nm. By exhibiting such a rare high-performance brominated acceptor, our work highlights the great potential for achieving record-breaking organic solar cells through delicately brominating.

Central Unit Fluorination of Non-Fullerene Acceptors Enables Highly Efficient Organic Solar Cells with Over 18 % Efficiency.

Halogenation of terminal of acceptors has been shown to give dramatic improvements in power conversion efficiencies (PCEs) of organic solar cells (OSCs). Similar significant results could be expected from the halogenation of the central units of state-of-the-art Y-series acceptors. Herein, a pair of acceptors, termed CH6 and CH4, featuring a conjugation-extended phenazine central unit with and without fluorination, have been synthesized. The fluorinated CH6 has enhanced molecular interactions and crystallinity, superior fibrillar network morphology and improved charge generation and transport in blend films, thus affording a higher PCE of 18.33 % for CH6-based binary OSCs compared to 16.49 % for the non-fluorinated CH4. The new central site offers further opportunities for structural optimization of Y-series molecules to afford better-performed OSCs and reveals the effectiveness of fluorination on central units.

Achieving over 18 % Efficiency Organic Solar Cell Enabled by a ZnO-Based Hybrid Electron Transport Layer with an Operational Lifetime up to 5†Years.

Although organic solar cells (OSCs) have delivered an impressive power conversion efficiency (PCE) of over 19 %, most of them demonstrated rather limited stability. So far, there are hardly any effective and universal strategies to improve stability of state-of-the-art OSCs. Herein, we developed a hybrid electron-transport layer (ETL) in inverted OSCs using ZnO and a new modifying agent (NMA), and significantly improved the stability and PCEs for all the tested devices. In particular, when applied in the D18 : N3 system, its inverted OSC exhibits so far the highest PCE (18.20 %) among inverted single-junction OSCs, demonstrating an extrapolated T80 lifetime of 7572 h (equivalent to 5 years under outdoor exposure). This is the first report with T80 over 5000 h among OSCs with over 18 % PCE. Furthermore, a high PCE of 16.12 % can be realized even in a large-area device (1 cm2 ). This hybrid ETL strategy provides a strong stimulus for highly prospective commercialization of OSCs.

All-Small-Molecule Organic Solar Cells with Efficiency Approaching 16% and FF over 80.

Molecule engineering has been demonstrated as a valid strategy to adjust the active layer morphology in all-small-molecule organic solar cells (ASM-OSCs). In this work, two non-fullerene acceptors (NFAs), FO-2Cl and FO-EH-2Cl, with different alkyl side chains are reported and applied in ASC-OSCs. Compared with FO-2Cl, FO-EH-2Cl is designed by replacing the octyl alkyl chains with branched iso-octyl alkyl chains, leading to an enhanced molecular packing, crystallinity, and redshifted absorption. With a small molecule BSFTR as donor, the device of BSFTR:FO-EH-2Cl obtains a better morphology and achieves a higher power conversion efficiency (PCE) of 15.78% with a notable fill factor (FF) of 80.44% than that of the FO-2Cl-based device with a PCE of 15.27% and FF of 78.41%. To the authors' knowledge, the FF of 80.44% is the highest value in ASM-OSCs. These results demonstrate a good example of fine-tuning the molecular structure to achieve suitable active layer morphology with promising performance for ASM-OSCs, which can provide valuable insight into material design for high-efficiency ASM-OSCs.

Spirocyclic side chain of a non-fullerene acceptor enables efficient organic solar cells with reduced recombination loss and energetic disorder.

Suppressing intramolecular vibration of non-fullerene acceptors (NFAs) by molecular rigidification has been proven to be an effective way to reduce the non-radiative recombination loss and energetic disorder of organic solar cells (OSCs). Thus far, extensive attention has been drawn on rigidifying the fused-ring backbones of NFAs, whereas the highly flexible alkyl side chains are barely concerned. Herein, an effective strategy of side chain rigidification by introducing a spiro-ring is developed for the first time and applied to construct the NFA of Spiro-F. Compared to its counterpart F-2F, the rigid spirocyclic side chain can constrain the vibrational-rotational motion and control the orientation of two highly flexible n-octyl chains effectively. As a result, an optimal molecular packing with enhanced intermolecular actions and lower energetic disorder is achieved by Spiro-F, endowing the OSC based on the as cast blend of PM6:Spiro-F with a significantly improved PCE of 13.56% and much reduced recombination loss compared to that of PM6:F-2F. This work provides a feasible strategy to achieve efficient OSCs through the rigidification of the side chain and could boost the PCEs further if applied to some other efficient systems with smaller bandgaps.

Pyrene-Based Dopant-Free Hole-Transport Polymers with Fluorine-Induced Favorable Molecular Stacking Enable Efficient Perovskite Solar Cells.

A new class of polymeric hole-transport materials (HTMs) are explored by inserting a two-dimensionally conjugated fluoro-substituted pyrene into thiophene and selenophene polymeric chains. The broad conjugated plane of pyrene and "Lewis soft" selenium atoms not only enhance the π-π stacking of HTM molecules greatly but also render a strong interaction with the perovskite surface, leading to an efficient charge transport/transfer in both the HTM layer and the perovskite/HTM interface. Note that fluorine substitution adjacent to pyrene boosts the stacking of HTMs towards a more favorable face-on orientation, further facilitating the efficient charge transport. As a result, perovskite solar cells (PSCs) employing PE10 as dopant-free HTM afford an excellent efficiency of 22.3 % and the dramatically enhanced device longevity, qualifying it among the best PSCs based on dopant-free HTMs.

A Phenanthrocarbazole-Based Dopant-Free Hole-Transport Polymer with Noncovalent Conformational Locking for Efficient Perovskite Solar Cells.

Adequate hole mobility is the prerequisite for dopant-free polymeric hole-transport materials (HTMs). Constraining the configurational variation of polymer chains to afford a rigid and planar backbone can reduce unfavorable reorganization energy and improve hole mobility. Herein, a noncovalent conformational locking via S-O secondary interaction is exploited in a phenanthrocarbazole (PC) based polymeric HTM, PC6, to fix the molecular geometry and significantly reduce reorganization energy. Systematic studies on structurally explicit repeats to targeted polymers reveals that the broad and planar backbone of PC remarkably enhances π-π stacking of adjacent polymers, facilitating intermolecular charge transfer greatly. The inserted "Lewis soft" oxygen atoms passivate the trap sites efficiently at the perovskite/HTM interface and further suppress interfacial recombination. Consequently, a PSC employing PC6 as a dopant-free HTM offers an excellent power conversion efficiency of 22.2 % and significantly improved longevity, rendering it as one of the best PSCs based on dopant-free HTMs.

Network Pharmacology-Based Study of the Underlying Mechanisms of Huangqi Sijunzi Decoction for Alzheimer's Disease.

BACKGROUND: Huangqi Sijunzi decoction (HQSJZD) is a commonly used conventional Chinese herbal medicine prescription for invigorating Qi, tonifying Yang, and removing dampness. Modern pharmacology and clinical applications of HQSJZD have shown that it has a certain curative effect on Alzheimer's disease (AD). METHODS: The active components and targets of HQSJZD were searched in the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP). The genes corresponding to the targets were retrieved using UniProt and GeneCard database. The herb-compound-target network and protein-protein interaction (PPI) network were constructed by Cytoscape. The core targets of HQSJZD were analysed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). The main active compounds of HQSJZD were docked with acetylcholinesterase (AChE). In vitro experiments were conducted to detect the inhibitory and neuroprotective effects of AChE. RESULTS: Compound-target network mainly contained 132 compounds and 255 corresponding targets. The main compounds contained quercetin, kaempferol, formononetin, isorhamnetin, hederagenin, and calycosin. Key targets contained AChE, PTGS2, PPARG, IL-1B, GSK3B, etc. There were 1708 GO items in GO enrichment analysis and 310 signalling pathways in KEGG, mainly including the cAMP signalling pathway, the vascular endothelial growth factor (VEGF) signalling pathway, serotonergic synapses, the calcium signalling pathway, type II diabetes mellitus, arginine and proline metabolism, and the longevity regulating pathway. Molecular docking showed that hederagenin and formononetin were the top 2 compounds of HQSJZD, which had a high affinity with AChE. And formononetin has a good neuroprotective effect, which can improve the oxidative damage of nerve cells. CONCLUSION: HQSJZD was found to have the potential to treat AD by targeting multiple AD-related targets. Formononetin and hederagenin in HQSJZD may regulate multiple signalling pathways through AChE, which might play a therapeutic role in AD.

Physalin B reduces Aß secretion through down-regulation of BACE1 expression by activating FoxO1 and inhibiting STAT3 phosphorylation.

Physalin B (PB), one of the major active steroidal constituents of Solanaceae Physalis plants, has a wide variety of biological activities. We found that PB significantly down-regulated ß-amyloid (Aß) secretion in N2a/APPsw cells. However, the underlying mechanisms are not well understood. In the current study, we investigated the changes in key enzymes involved in ß-amyloid precursor protein (APP) metabolism and other APP metabolites by treating N2a/APPsw cells with PB at different concentrations. The results indicated that PB reduced Aß secretion, which was caused by down-regulation of ß-secretase (BACE1) expression, as indicated at both the protein and mRNA levels. Further research revealed that PB regulated BACE1 expression by inducing the activation of forkhead box O1 (FoxO1) and inhibiting the phosphorylation of signal transducer and activator of transcription 3 (STAT3). In addition, the effect of PB on BACE1 expression and Aß secretion was reversed by treatment with FoxO1 siRNA and STAT3 antagonist S3I-201. In conclusion, these data demonstrated that PB can effectively down-regulate the expression of BACE1 to reduce Aßsecretion by activating the expression of FoxO1 and inhibiting the phosphorylation of STAT3.