Efficient and Stable All-Polymer Solar Cells Enabled by Dual Working Mechanism.

Ternary strategy with integration characteristics and adaptability is a simple and effective method for blooming of the performance of photovoltaic devices. Herein, a novel wideband gap polymer donor PBB2-Hs is synthesized as the guest component to optimize all-polymer solar cells (all-PSCs). High-energy photon absorption and long exciton lifetime of PBB2-Hs constitute efficient energy transfer. Good miscibility and cascade energy levels promote the formation of alloy-like structure between PBB2-Hs and host system. The dual working mechanisms greatly improve photon capture and charge transfer in active layers. Additionally, the introduction of PBB2-Hs also optimizes the ordered molecular stacking of acceptors and suppresses molecular peristalsis. Upon adding 15 wt% PBB2-Hs, the ternary all-PSC achieved a champion efficiency of 17.66%, and can still maintain 82% photostability (24 h) and 91% storage stability (1000 h) of the original PCE. Moreover, the strong molecular stacking and entanglement between PBB2-Hs and the host material increased the elongation at break of ternary blend film by 1.6 times (16.2%), allowing the flexible device to maintain 83% of the original efficiency after 800 bends (R = 5 mm). This work highlights the effectiveness of guest polymer on simultaneously improving photovoltaic performance, photostability and mechanical stability in all-PSCs.

Two Well-Compatible Acceptors with Efficient Energy Transfer Enable Ternary Organic Photovoltaics Exhibiting a 13.36% Efficiency.

Organic photovoltaics (OPVs) are fabricated with PM6 as donor and T6Me, IT-2F, or their mixture as acceptor. A 13.36% power conversion efficiency (PCE) is achieved from the optimized ternary OPVs with 50 wt% IT-2F in acceptors, which is attributed to the enhanced photon harvesting of ternary active layers and improved exciton utilization efficiency through energy transfer from IT-2F to T6Me. The efficient energy transfer from IT-2F to T6Me can be confirmed from the photoluminescence spectra of neat and blend films, which may provide additional channels to enhance exciton utilization efficiency for achieving short-circuit current density (JSC ) improvement of ternary OPVs. It should be highlighted that the fill factor (FF) of ternary OPVs can be monotonously increased along with the incorporation of IT-2F, indicating the gradually optimized phase separation degree of ternary active layers. The third component IT-2F plays a key role in optimizing phase separation as a morphology regulator. Over 8% PCE improvement is achieved in the optimized ternary OPVs compared with the over 12% PCEs of the corresponding binary OPVs, respectively. This work indicates that the performance of ternary OPVs can be well optimized by carefully picking materials with good compatibility and complementary absorption spectra, as well as the appropriate energy levels.

One key issue in characterization of organic solar cells with solution processed interfacial layers.

Solution processed interfacial layers are commonly employed in bulk heterojunction organic solar cells (OSCs) for better charge collection. PDIN interfacial layers were prepared by employing a static or dynamic spin coating method from PDIN methanol solution, and defined as the S-PDIN or D-PDIN layer. The OSCs with a S-PDIN layer exhibit 13.88% power conversion efficiency (PCE) with a virtual high short circuit density (JSC) of 26.45 mA cm-2 and relatively low fill factor (FF) of 58.94% during the current density versus voltage (J-V) measurement without a shadow mask. 12.56% PCE is achieved for OSCs with a D-PDIN layer, along with a JSC of 18.85 mA cm-2 and FF of 74.88%. Over 77% FFs are obtained for OSCs with a S-PDIN or D-PDIN layer during J-V measurement with a shadow mask, and both OSCs exhibit a very similar JSC and PCE. The virtual high JSCs and relatively low FF of OSCs with a S-PDIN layer may be due to the enhanced conductivity of PEDOT:PSS during preparation of the PDIN layer by the SSC method, which can be further confirmed from the OSCs with a methanol treated PEDOT:PSS layer. This work indicates that a well-balanced JSC and FF should be an important evaluating indicator for efficient OSCs, and an appropriate shadow mask is necessary to measure the J-V curves of OSCs with a solution processed interfacial layer.

Unveiling value patterns via deep reinforcement learning in heterogeneous data analytics.

Artificial intelligence has substantially improved the efficiency of data utilization across various sectors. However, the insufficient filtering of low-quality data poses challenges to uncertainty management, threatening system stability. In this study, we introduce a data-valuation approach employing deep reinforcement learning to elucidate the value patterns in data-driven tasks. By strategically optimizing with iterative sampling and feedback, our method is effective in diverse scenarios and consistently outperforms the classic methods in both accuracy and efficiency. In China's wind-power prediction, excluding 25% of the overall dataset deemed low-value led to a 10.5% improvement in accuracy. Utilizing just 42.8% of the dataset, the model discerned 80% of linear patterns, showcasing the data's intrinsic and transferable value. A nationwide analysis identified a data-value-sensitive geographic belt across 10 provinces, leading to robust policy recommendations informed by variances in power outputs and data values, as well as geographic climate factors.

5G and energy internet planning for power and communication network expansion.

Our research addresses the critical intersection of communication and power systems in the era of advanced information technologies. We highlight the strategic importance of communication base station placement, as its optimization is vital for minimizing operational disruptions in energy systems. Our study introduces a communications and power coordination planning (CPCP) model that encompasses both distributed energy resources and base stations to improve communication quality of service. This model facilitates optimal resource distribution, ensuring communication reliability over 96% and downlink transmission rates above 450 Mbps, enhancing network resilience and cost-effectiveness. Through case studies, we demonstrate CPCP's potential to significantly reduce planning costs, particularly with increased renewable energy integration, supporting the transition to low-carbon energy systems. Our findings contribute to a comprehensive understanding of the symbiotic relationship between communication and power networks, emphasizing the need for coordinated planning in building future-proof energy infrastructures.

Structure-Activity Relationship between Crystallinity and Carrier Transport of Two-Dimensional Donor Units in Organic Solar Cells.

Benzo[1,2-b:4,5-b']dithiophene (BDT) and its derivatives have made important contributions to constructing high-performance polymers. However, it is difficult to clarify the real role of donor units due to the interference of strong electronegativity and crystallinity of acceptor units in the D-A copolymer. Here, we design a cyclohexane-substituted dithieno[3,2-f:2',3'-h]quinoxaline (DTQ)-based acceptor unit with successfully destroyed crystallinity and charge transport. Three donor-dominated materials PQH-BTF, PQH-BTCl, and PQH-BFCl are obtained. It is found that the materials exhibit obvious differences after destroying the crystallization and charge transport of the acceptor unit, and the real role of different two-dimensional donor units in designed polymers is confirmed. The backbone BDF exhibits much stronger intermolecular interactions compared to BDT, while the side chain ThF demonstrates a higher crystallization capacity than that of ThCl. More interestingly, it can be inferred that the molecular backbone is likely to construct miscible-phase crystallization (D-A crystal) while the side chain tends to demonstrate a capacity for pure-phase crystallization (D-D crystal) in a 2D donor system. Different crystallization leads to different exciton transport: pure-phase crystallization is conducive to the reduction of trap-assisted recombination, while miscible crystallization is beneficial to the reduction of bimolecular recombination. This work can help to choose donor units more accurately when preparing D-A copolymers.

Non-Fused π-Extension of Endcaps of Small Molecular Acceptors Enabling High-Performance Organic Solar Cells.

The modular structure of small molecular acceptors (SMAs) allows for versatile modifications of the materials and boosts the photovoltaic efficiencies of organic solar cells (OSCs) in recent years. As a critical component, the endcaps of SMAs have been intensively investigated and modified to control the molecular aggregation and photo-electronic conversion. However, most of the studies focus on halogenation or π-fusion extension of the endcap moieties, but overlook the non-fused π-extension approach, which could be a promising strategy to balance the self-aggregation and compatibility behaviors. Herein, we reported two new acceptors namely BTP-Th and BTP-FTh based on non-fused π-extension of the endcap by chlorinated-thiophene, of which the latter molecule has better co-planarity and crystallinity because of the intramolecular noncovalent interactions. Paired with donor PBDB-T, the optimal device of BTP-FTh reveals a greater efficiency of 14.81 % that that of BTP-Th (13.91 %). Nevertheless, the BTP-Th based device realizes a lower energy loss, enabling BTP-Th as a good candidate to serve as guest acceptor. As a result, the ternary solar cells of PM6 : BTP-eC9 : BTP-Th output a champion efficiency up to 18.71 % with enhanced open-circuit voltage. This study highlights the significance of rational decoration of endcaps for the design of high-performance SMAs and photovoltaic cells.

Fouling evolution of extracellular polymeric substances in forward osmosis based microalgae dewatering.

Membrane fouling was still a challenge for the potential application of forward osmosis (FO) in algae dewatering. In this study, the fouling behaviors of Chlorella vulgaris and Scenedesmus obliquus were compared in the FO membrane filtration process, and the roles of their soluble-extracellular polymeric substances (sEPS) and bound-EPS (bEPS) in fouling performance were investigated. The results showed that fouling behaviors could be divided into two stages including a quickly dropped and later a stable process. The bEPS of both species presented the highest flux decline (about 40.0%) by comparison with their sEPS, cells and broth. This performance was consistent with the largest dissolved organic carbon losses in feed solutions, and the highest interfacial free energy analyzed by the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory. The chemical characterizations of algal foulants further showed that the severe fouling performance was also consistent with a proper ratio of carbohydrates and proteins contents in the cake layer, as well as the higher low molecular weight (LMW) components. Compared with the bEPS, the sEPS was crucial for the membrane fouling of S. obliquus, and an evolution of the membrane fouling structure was found in both species at the later filtration stage. This work clearly revealed the fundamental mechanism of FO membrane fouling caused by real microalgal suspension, and it will improve our understanding of the evolutionary fouling performances of algal EPS.

Embedded Host/Guest Alloy Aggregations Enable High-Performance Ternary Organic Photovoltaics.

The ternary strategy has been intensively studied to improve the power conversion efficiencies of organic photovoltaics. Thereinto, the location of the guest component plays a critical role, but few reports have been devoted to this concern. Hereon, the distribution of LA1 as a guest acceptor in a variety of ternary scenarios is reported and the dominating driving forces of managing the guest distribution and operating modes are outlined. Governed by the appropriate relationship of compatibility, crystallinity, and surface energies between host and guest acceptors, as well as interfacial interactions between donor and dual acceptors, most of the LA1 molecules permeate into the internal of host acceptor phases, forming embedded host/guest alloy-like aggregations. The characteristic distributions greatly optimize the morphologies, maximize energy transfer, and enhance exciton/charge behaviors. Particularly, PM6:IT-4F:LA1 ternary cells afford high efficiency of 15.27% with impressive fill factors (FF) over 81%. The popularization studies further verify the superiority of the LA1-involved alloy structures, and with the Y6-family acceptor as the host component, an outstanding efficiency of 19.17% is received. The results highlight the importance of guest distribution in ternary systems and shed light on the governing factors of distributing the guests in ternary cells.

Over 19% Efficiency Organic Solar Cells by Regulating Multidimensional Intermolecular Interactions.

Research on organic solar cells (OSCs) has progressed through material innovation and device engineering. However, well-known and ubiquitous intermolecular interactions, and particularly their synergistic effects, have received little attention. Herein, the complicated relationship between photovoltaic conversion and multidimensional intermolecular interactions in the active layers is investigated. These interactions are dually regulated by side-chain isomerization and end-cap engineering of the acceptors. The phenylalkyl featured acceptors (LA-series) exhibit stronger crystallinity with preferential face-on interactions relative to the alkylphenyl attached isomers (ITIC-series). In addition, the PM6 and LA-series acceptors exhibit moderate donor/acceptor interactions compared to those of the strongly interacting PM6/ITIC-series pairs, which helps to enhance phase separation and charge transport. Consequently, the output efficiencies of all LA series acceptors are over 14%. Moreover, LA-series acceptors show appropriate compatibility, host/guest interactions, and crystallinity relationships with BTP-eC9, thereby leading to uniform and well-organized "alloy-like" mixed phases. In particular, the highly crystalline LA23 further optimizes multiple interactions and ternary microstructures, which results in a high efficiency of 19.12%. Thus, these results highlight the importance of multidimensional intermolecular interactions in the photovoltaic performance of OSCs.

Renewable-to-ammonia: Configuration strategy and technoeconomic analysis.

The increasing demand for chemical raw materials has provided opportunities for the ammonia (NH3) industry. However, little attention has been devoted to the economic feasibility of renewable-to-ammonia (RE2A). Therefore, this paper proposes a technoeconomic model to research the optimal capacity configuration and quantify the levelized cost of ammonia (LCOA) for RE2A, which is a retrofitted plant based on coal-to-ammonia (C2A). A cost model of C2A is established as a benchmark to evaluate the economic feasibility of RE2A. A case study in Inner Mongolia is adopted, which shows that the monthly NH3 output is 7-11×103t, which satisfies actual industrial production. The LCOA of RE2A is 469$/t, with investment in wind turbines accounting for 58%, which is lower than the NH3 market price (605$-650$/t). The LCOA of RE2A will equal that of C2A with a carbon tax of 47.1$/t CO2, which confirms the economic advantages of RE2A in the future.

Inherent spatiotemporal uncertainty of renewable power in China.

Solar and wind resources are vital for the sustainable energy transition. Although renewable potentials have been widely assessed in existing literature, few studies have examined the statistical characteristics of the inherent renewable uncertainties arising from natural randomness, which is inevitable in stochastic-aware research and applications. Here we develop a rule-of-thumb statistical learning model for wind and solar power prediction and generate a year-long dataset of hourly prediction errors of 30 provinces in China. We reveal diversified spatiotemporal distribution patterns of prediction errors, indicating that over 60% of wind prediction errors and 50% of solar prediction errors arise from scenarios with high utilization rates. The first-order difference and peak ratio of generation series are two primary indicators explaining the uncertainty distribution. Additionally, we analyze the seasonal distributions of the provincial prediction errors that reveal a consistent law in China. Finally, policies including incentive improvements and interprovincial scheduling are suggested.

Research on recognition and classification of pulse signal features based on EPNCC.

To rapidly obtain the complete characterization information of pulse signals and to verify the sensitivity and validity of pulse signals in the clinical diagnosis of related diseases. In this paper, an improved PNCC method is proposed as a supplementary feature to enable the complete characterization of pulse signals. In this paper, the wavelet scattering method is used to extract time-domain features from impulse signals, and EEMD-based improved PNCC (EPNCC) is used to extract frequency-domain features. The time-frequency features are mixed into a convolutional neural network for final classification and recognition. The data for this study were obtained from the MIT-BIH-mimic database, which was used to verify the effectiveness of the proposed method. The experimental analysis of three types of clinical symptom pulse signals showed an accuracy of 98.3% for pulse classification and recognition. The method is effective in complete pulse characterization and improves pulse classification accuracy under the processing of the three clinical pulse signals used in the paper.

Exploring the trade-offs between electric heating policy and carbon mitigation in China.

China has enacted a series of policies since 2015 to substitute electricity for in-home combustion for rural residential heating. The Electric Heating Policy (EHP) has contributed to significant improvements in air quality, benefiting hundreds of millions of people. This shift, however, has resulted in a sharp increase in electric loads and associated carbon emissions. Here, we show that China's EHP will greatly increase carbon emissions. We develop a theoretical model to quantify the carbon emissions from power generation and rural residential heating sectors. We found that in 2015, an additional 101.69-162.89 megatons of CO2 could potentially be emitted if EHP was implemented in 45-55% of rural residents in Northern China. In 2020, the incremental carbon emission is expected to reach 130.03-197.87 megatons. Fortunately, the growth of carbon emission will slow down due to China's urbanization progress. In 2030, the carbon emission increase induced by EHP will drop to 119.19-177.47 megatons. Finally, we conclude two kinds of practical pathways toward low-carbon electric heating, and provide techno-economic analyses.

Graphdiyne Derivative as Multifunctional Solid Additive in Binary Organic Solar Cells with 17.3% Efficiency and High Reproductivity.

Morphology tuning of the blend film in organic solar cells (OSCs) is a key approach to improve device efficiencies. Among various strategies, solid additive is proposed as a simple and new way to enable morphology tuning. However, there exist few solid additives reported to meet such expectations. Herein, chlorine-functionalized graphdiyne (GCl) is successfully applied as a multifunctional solid additive to fine-tune the morphology and improve device efficiency as well as reproductivity for the first time. Compared with 15.6% efficiency for control devices, a record high efficiency of 17.3% with the certified one of 17.1% is obtained along with the simultaneous increase of short-circuit current (Jsc ) and fill factor (FF), displaying the state-of-the-art binary organic solar cells at present. The redshift of the film absorption, enhanced crystallinity, prominent phase separation, improved mobility, and decreased charge recombination synergistically account for the increase of Jsc and FF after introducing GCl into the blend film. Moreover, the addition of GCl dramatically reduces batch-to-batch variations benefiting mass production owing to the nonvolatile property of GCl. All these results confirm the efficacy of GCl to enhance device performance, demonstrating a promising application of GCl as a multifunctional solid additive in the field of OSCs.

Comparative transcriptome analysis reveals phytohormone signalings, heat shock module and ROS scavenger mediate the cold-tolerance of rubber tree.

Two contrasting cold response rubber tree clones, the cold-resistant '93-114' and cold-sensitive 'Reken501', were subject to a global transcriptome response assessing via high-throughput RNA-seq technique and comprehensive bioinformatics analysis using the referenced rubber tree genome with the purpose of exploring the potential molecular cues underlying the tolerance of rubber trees to cold stress. As a result, a total of 1919 genes had significantly higher expression, while 2929 genes had significantly lower expression in '93-114' than in 'Reken501' without cold stress. Upon cold stress, the numbers of genes with significantly higher expression decreased to 1501 at 1 h treatment and to 1285 at 24 h treatment in '93-114' than that of 'Reken501', conversely, the numbers of genes with significantly lower expression increased to 7567 at 1 h treatment and to 5482 at 24 h treatment. Functional annotation of the differentially expressed genes between '93-114' and 'Reken501' suggests that down-regulation of auxin and ethylene signaling and activation of heat shock module and ROS scavengers is a primary strategy for H. brasiliensis to cope with cold stress. Our identified vital differentially expressed genes may be beneficial for elucidation of the molecular mechanisms underlying cold tolerance and for genetic improvement of H. brasiliensis clones.

[Selection of light source used for plant cultivation in controlled ecological life support system].

OBJECTIVE: To select suitable light source for higher plant cultivation in the controlled ecological life support system of the future space station. METHOD: The experiment was carried out in the Space Higher Plant Cultivation Ground-based Experimental Facility (SHPCGEF); four combinations of two red and blue light-emitting diode (LED) were utilized as light sources; soilless cultivation technique with porous ceramic tubes and porous ceramic particles was utilized in the growth system. RESULT: The plants grown under the shelf of pure red LED showed a lying-down state in early stage, and stood erect in later period with slender and long stems; the plants under various combinations of red and blue LED grew with nearly normal state, but the plants under the combination of 90% red and 10% blue LED possessed the best comprehensive indexes. CONCLUSION: The normal growth and development of plantlets needs two light sources of red and blue LED, and the combination of 90% red and 10% blue LED is the optimum one among those tested combinations.

Selection of root-zone media for higher plant cultivation in space.

OBJECTIVE: To investigate the cultivating effects of several mineral matters used as root-zone media for higher plant growth in space. METHOD: Four kinds of artificial and natural mineral matters were used as plant root-zone media based on lots of investigation and analysis. Nutrient liquid was delivered into the media by a long capillary material, and roots of plants obtained nutrition and water from the media. The related parameters such as plant height and photosynthetic efficiency were measured and analyzed. RESULT: The growing effect in a mixture of coarse and fine ceramic particles with equal quantity proportion was the best, that in fine ceramic particles was the second best, that in clinoptilolite particles was the third and that in diorite particles was the last. CONCLUSION: The mixture of coarse and fine ceramic particles with equal quantity possesses not only fine capillary action, but also good aerating ability, and therefore is capable of being utilized as an effective root-zone media for higher plants intended to be grown in space.