Redox-Sensitive NiOx Stabilizing Perovskite Films for High-Performance Photovoltaics.

Metal halide perovskite materials inherently possess imperfections, particularly under nonequilibrium conditions, such as exposure to light or heat. To tackle this challenge, we introduced stearate ligand-capped nickel oxide (NiOx), a redox-sensitive metal oxide with variable valence, into perovskite intermediate films. The integration of NiOx improved the efficiency and stability of perovskite solar cells (PSCs) by offering multifunctional roles: (1) chemical passivation for ongoing defect repair, (2) energetic passivation to bolster defect tolerance, and (3) field-effect passivation to mitigate charge accumulation. Employing a synergistic approach that tailored these three passivation mechanisms led to a substantial increase in the devices' efficiencies. The target cell (0.12 cm2) and module (18 cm2) exhibited efficiencies of 24.0 and 22.9%, respectively. Notably, the encapsulated modules maintained almost 100 and 87% of the initial efficiencies after operating for 1100 h at the maximum power point (60 °C, 50% RH) and 2000 h of damp-heat testing (85 °C, 85% RH), respectively. Outdoor real-time tests further validated the commercial viability of the NiOx-assisted PSMs. The proposed passivation strategy provides a practical and uncomplicated approach for fabricating high-efficiency and stable photovoltaics.

Cross-domain mechanism for few-shot object detection on Urine Sediment Image.

Deep learning object detection networks require a large amount of box annotation data for training, which is difficult to obtain in the medical image field. The few-shot object detection algorithm is significant for an unseen category, which can be identified and localized with a few labeled data. For medical image datasets, the image style and target features are incredibly different from the knowledge obtained from training on the original dataset. We propose a background suppression attention(BSA) and feature space fine-tuning module (FSF) for this cross-domain situation where there is a large gap between the source and target domains. The background suppression attention reduces the influence of background information in the training process. The feature space fine-tuning module adjusts the feature distribution of the interest features, which helps to make better predictions. Our approach improves detection performance by using only the information extracted from the model without maintaining additional information, which is convenient and can be easily plugged into other networks. We evaluate the detection performance in the in-domain situation and cross-domain situation. In-domain experiments on the VOC and COCO datasets and the cross-domain experiments on the VOC to medical image dataset UriSed2K show that our proposed method effectively improves the few-shot detection performance.

Interfacial Property Tuning Enables Copper Electrodes in High-Performance n-i-p Perovskite Solar Cells.

Developing cost-effective metal electrodes is essential for reducing the overall cost of perovskite solar cells (PSCs). Although copper is highly conductive and economical, it is rarely used as a positive electrode in efficient n-i-p PSCs due to its unmatched Fermi level and low oxidation threshold. We report herein that modification for the inner surface of electrodes using mercaptopyridine-based molecules readily tunes the electronic and chemical properties of copper, which has been achieved by fine-tuning the substituents of mercaptopyridines. The systematic adjustment for the Fermi level and oxidation potential of copper facilitates interfacial hole extraction and enhances the oxidation resistance of copper electrodes, which enables pure copper electrodes to be used in high-performance n-i-p PSCs with different hole transport materials. The resulting PSCs with copper electrodes display excellent power conversion efficiency and long-term stability, even comparable to those of the gold electrodes, showing great potential in the manufacturing and commercialization of PSCs.

Tailoring the Interface with a Multifunctional Ligand for Highly Efficient and Stable FAPbI3 Perovskite Solar Cells and Modules.

Perovskite solar cells (PeSCs) using FAPbI3 perovskite films often exhibit unfavorable phase transitions and defect-induced nonradiative interfacial recombination, resulting in considerable energy loss and impairing the performance of PeSCs in terms of efficiency, stability, and hysteresis. In this work, a facile interface engineering strategy to control the surface structure and energy-level alignment of perovskite films by tailoring the interface between the FAPbI3 film and hole-transporting layer using 4-hydroxypicolinic acid (4HPA) is reported. According to density functional theory studies, 4HPA has prominent electron delocalization distribution properties that enable it to anchor to the perovskite film surface and facilitate charge transfer at the interface. By enabling multiple bonding interactions with the perovskite layer, including hydrogen bonds, PbO, and PbN dative bonds, 4HPA passivation significantly reduces the trap density and efficiently suppresses nonradiative recombination. The obtained perovskite films exhibit superior optoelectronic properties with improved crystallinity, pure α-phase FAPbI3 , and favorable energy band bending. Following this strategy, 4HPA post-treatment PeSCs achieve a champion power conversion efficiency of 23.28% in 0.12 cm2 cells and 19.26% in 36 cm2 modules with excellent environmental and thermal stabilities.

Conformal Imidazolium 1D Perovskite Capping Layer Stabilized 3D Perovskite Films for Efficient Solar Modules.

Although the perovskite solar cells have been developed rapidly, the industrialization of perovskite photovoltaics is still facing challenges, especially considering their stability issues. Here, the new type of benzimidazolium salt, N,N'-dialkylbenzimidazolium iodide, is proposed and functionalized to convert the three-dimensional (3D) FACs-perovskite films into one-dimensional (1D) capping layer topped 1D/3D structure either in individual device or module levels. This conformal interface modulation demonstrates that not only can effectively stabilize FACs-based perovskite films by inhibiting the lateral and vertical iodide diffusions in devices or modules, ensuring an excellent operation and environmental stability, but also provides an excellent charge transporting channel through the well-designed 1D crystal structure. Consequently, efficient device performance with power conversion efficiency up to 24.3% is readily achieved. And the large-area perovskite solar modules with high efficiency (19.6% for the active areas of 18 cm2 ) and long-term stability (about 500 h in AM 1.5G illumination or about 1000 h under double-85 conditions) are also successfully verified.

Solvent Gaming Chemistry to Control the Quality of Halide Perovskite Thin Films for Photovoltaics.

Research on solvent chemistry, particularly for halide perovskite intermediates, has been advancing the development of perovskite solar cells (PSCs) toward commercial applications. A predictive understanding of solvent effects on the perovskite formation is thus essential. This work systematically discloses the relationship among the basicity of solvents, solvent-contained intermediate structures, and intermediate-to-perovskite α-FAPbI3 evolutions. Depending on their basicity, solvents exhibit their own favorite bonding selection with FA+ or Pb2+ cations by forming either hydrogen bonds or coordination bonds, resulting in two different kinds of intermediate structures. While both intermediates can be evolved into α-FAPbI3 below the δ-to-α thermodynamic temperature, the hydrogen-bond-favorable kind could form defect-less α-FAPbI3 via sidestepping the break of strong coordination bonds. The disclosed solvent gaming mechanism guides the solvent selection for fabricating high-quality perovskite films and thus high-performance PSCs and modules.

85 °C/85%-Stable n-i-p Perovskite Photovoltaics with NiOx Hole Transport Layers Promoted By Perovskite Quantum Dots.

Power conversion efficiency (PCE) and long-term stability are two vital issues for perovskite solar cells (PSCs). However, there is still a lack of suitable hole transport layers (HTLs) to endow PSCs with both high efficiency and stability. Here, NiOx nanoparticles are promoted as an efficient and 85 °C/85%-stable inorganic HTL for high-performance n-i-p PSCs, with the introduction of perovskite quantum dots (QDs) between perovskite and NiOx as systematic interfacial engineering. The QD intercalation enhances film morphology and assembly regulation of NiOx HTLs . Due to structure-function correlations, hole mobility within NiOx HTL is improved. And the hole extraction from perovskite to NiOx is also facilitated, resulting from reduced trap states and optimized energy level alignments. Hence, the promoted NiOx -based n-i-p PSCs exhibit high PCE (21.59%) and excellent stability (sustaining 85 °C aging in air without encapsulation). Furthermore, encapsulated solar modules with QDs-promoted NiOx HTLs show impressive stability during 85 °C/85% aging test for 1000 hours. With high transparency, QDs-promoted NiOx is also demonstrated to be an advanced HTL for semitransparent PSCs. This work develops promising NiOx inorganic HTL in n-i-p PSCs for manufacturing next-generation photovoltaic devices.

Leptin activates the JAK/STAT pathway to promote angiogenesis in RF/6A cells in vitro.

AIM: To investigate the effect of leptin on the angiogenesis of RF/6A cells (monkey retinal choroidal endothelial cells) in vitro and test the cellular signaling in the mechanism. METHODS: RF/6A cells were cultured in vitro and randomly divided into four groups: normal control, with leptin at 50, 100, 200 ng/mL for cell counting kit-8 (CCK8). RF/6A cell proliferation and migration were examined by Transwell assays, while RF/6A cell tube formation by Matrigel assay. JAK2, p-JAK2, STAT3, and p-STAT3 protein expression was measured by Western blotting. Cells were then divided into the following treatment groups: control, 100 ng/mL leptin and AG-490 (100 ng/mL leptin+10 µmol/L AG-490) for examinations of RF/6A cellular behaviour again. Analysis of differences was carried out using one-way ANOVA and least significant difference (LSD). RESULTS: RF/6A cell proliferation, migration and cell tube formation were promoted significantly by leptin in a dose-dependent manner (P<0.05). Western blotting showed that leptin up-regulated p-JAK2 and p-STAT3 expression levels. Treatment with the JAK/STAT pathway inhibitor, AG-490, decreased leptin-induced p-JAK2 and p-STAT3 expression, and inhibited cell proliferation, migration and cell tube formation induced by leptin (P<0.05). CONCLUSION: Leptin can promote RF/6A cell angiogenesis in vitro via activation of the JAK2/STAT3 signaling pathway.

Promotion Strategies of Hole Transport Materials by Electronic and Steric Controls for n-i-p Perovskite Solar Cells.

Hole transport materials (HTMs) play a requisite role in n-i-p perovskite solar cells (PSCs). The properties of HTMs, such as hole extraction efficiency, chemical compatibility, film morphology, ion migration barrier, and so on, significantly affect PSCs' power conversion efficiencies (PCEs) and stabilities. Up till now, researchers have devoted much attention to developing new types of HTMs as well as promoting pristine HTMs using numerous strategies. In this Review, we summarize the design strategies of various common HTMs for n-i-p PSCs are comprehensively discussed from two separate aspects (additive and non-additive engineering). Additive engineering generally tunes electronic properties of HTMs while non-additive engineering basically modifies their steric structures. Critical analysis and comparison between these design strategies are provided, considering the overall PCEs and stabilities of PSCs. Finally, a brief perspective on future promising design strategies for HTMs is given, in order to fabricate efficient and stable n-i-p devices for the commercialization of PSCs.

Intermediate Chemistry of Halide Perovskites: Origin, Evolution, and Application.

The preparation of solution-processed metal halide perovskites is interwoven with research on their intermediate chemistry. In this Perspective, molecule-level insights are provided into how Lewis base additives (LBAs), e.g., DMSO and NMP, facilitate powder-to-film formation processes (i.e., the chemical origin of intermediate structures, structural evolution of intermediate-to-perovskite phase transition, and device-based application of intermediate-evolved perovskites). LBAs interact with Lewis acid species (cationic A+ or B2+ sites) of ABX3 structures with separate probability in terms of coordination bonds or hydrogen bonds to form two types of intermediate structures, inducing significant differences within intermediate-to-perovskite processes. In addition, in-depth understanding of intermediate chemistry favors the multifaceted applications of solution-processed perovskites. A brief summary is finally provided together with a perspective on how intermediate chemistry determines perovskite properties and applications.

Sulfonate-Assisted Surface Iodide Management for High-Performance Perovskite Solar Cells and Modules.

Owing to the ionic nature of lead halide perovskites, their halide-terminated surface is unstable under light-, thermal-, moisture-, or electric-field-driven stresses, resulting in the formation of unfavorable surface defects. As a result, nonradiative recombination generally occurs on perovskite films and deteriorates the efficiency, stability, and hysteresis performances of perovskite solar cells (PSCs). Here, a surface iodide management strategy was developed through the use of cesium sulfonate to stabilize the perovskite surface. It was found that the pristine surface of common perovskite was terminated with extra iodide, that is, with an I-/Pb2+ ratio larger than 3, explaining the origination of surface-related problems. Through post-treatment of perovskite films by cesium sulfonate, the extra iodide on the surface was facilely removed and the as-exposed Pb2+ cations were chelated with sulfonate anions while maintaining the original 3D perovskite structure. Such iodide replacement and lead chelating coordination on perovskite could reduce the commonly existing surface defects and nonradiative recombination, enabling assembled PSCs with an efficiency of 22.06% in 0.12 cm2 cells and 18.1% in 36 cm2 modules with high stability.

Different effects of anti-VEGF drugs (Ranibizumab, Aflibercept, Conbercept) on autophagy and its effect on neovascularization in RF/6A cells.

INTRODUCTION: Choroidal neovascularization (CNV) is the main pathological change of wet age-related macular degeneration. Anti-VEGF drugs are the most commonly used treatment for CNV. The biggest drawback of anti-VEGF drugs is the recurrence of CNV, which requires repeated therapy several times. Autophagy activation may be involved in reducing the therapeutic effect of anti-VEGF drugs. So, this study aims to elucidate the effect and mechanism of anti-VEGF drugs on endothelial autophagy and neovascularization in vitro. METHODS: RF/6A cells were randomly divided into five groups: The control group, hypoxia group (1% O2, 5% CO2, 94% N2), anti-VEGF group (group1: Ranibizumab 100 µg/ml; group2: Aflibercept, 400 µg/ml; group3: Conbercept, 100 µg/ml). Autophagy-related proteins were examined by Western blot. RFP-GFP-LC3 was used to detect autophagy and autophagic flow. Subsequently, we used autophagy inhibitors (3-MA or CQ) to inhibit Conbercept induced autophagy and to observe its effect on angiogenesis in vitro. Proliferation, migration, and tube formation of endothelial cells can be used to study neovascularization in vitro. In this research, the CCK-8 assay was used to detect cell proliferation. Cell migration and tube formation were assessed by wound assay and matrix method, respectively. Flow cytometry and Tunel were used to detect cell apoptosis. Finally, the mechanism of Conbercept activated autophagy was studied. Western blot was used to detect the expression of p53 and DRAM (damage-regulated autophagy modulator), upstream activators of autophagy. RESULTS: The protein levels of Beclin-1 and LC3-2/1 in Ranibizumab and Conbercept groups were significantly higher than in the hypoxia group(P < 0.05). While the expression of P62 was decreased (P < 0.05). The autophagic flux was showed the same results. However, Aflibercept showed the opposite effect on autophagy. Compared with the Conbercept group, autophagy inhibitor 3-MA or CQ can further inhibit cell proliferation and promotes cell apoptosis (P < 0.05). Conbercept significantly inhibited cell migration compared with the hypoxia group (633.08 ± 72.52 vs. 546.33 ± 24.61), while the autophagy inhibitor group (3-MA or CQ) had a more obvious inhibition effect (309.75 ± 86.36 and 263.33 ± 68.67) (P < 0.05). For tube formation, the number of tube formation was decreased significantly in the Conbercept group (32.00 ± 2.00) compared to the hypoxia group (39.00 ± 1.53) and even further reduced in 3-MA or CQ group (24.00 ± 3.61, 20.00 ± 2.65). The length of master segments in the hypoxia group was 15,668.00 ± 894.11. It was decreased in Conbercept (13,885.34 ± 730.03). In 3-MA or CQ group, the length of master segments dropped further (11,997.00 ± 433.66, 10,617.67 ± 543.21). Compare with the hypoxia group, the expression P53 and DRAM were increased in the Conbercept group (P < 0.05). Autophagy-related proteins LC-3, Beclin-1, and DRAM were inhibited by P53 inhibitor Pifithrin-α (PFTα) (P < 0.05). CONCLUSION: Ranibizumab and Conbercept can trigger the autophagy of vascular endothelial cells while Aflibercept can inhibit it. The combination of Conbercept and autophagy inhibitor can significantly inhibit the formation of angiogenesis in vitro. The mechanism of autophagy activation is related to the activation of the p53/DRAM pathway.

Perovskite Quantum Dots as Multifunctional Interlayers in Perovskite Solar Cells with Dopant-Free Organic Hole Transporting Layers.

Perovskite solar cells (PSCs) with organic hole transporting layers (o-HTLs) have been widely studied due to their convenient solution processing, but it remains a big challenge to improve the hole mobilities of commercially available organic hole transporting materials without ion doping while maintaining the stability of PSCs. In this work, we demonstrated that the introduction of perovskite quantum dots (QDs) as interlayers between perovskite layers and dopant-free o-HTLs (P3HT, PTAA, Spiro-OMeTAD) resulted in a significantly enhanced performance of PSCs. The universal role of QDs in improving the efficiency and stability of PSCs was validated, exceeding that of lithium doping. After a deep examination of the mechanism, QD interlayers provided the multifunctional roles as follows: (1) passivating the perovskite surface to reduce the overall amount of trap states; (2) promoting hole extraction from perovskite to dopant-free o-HTLs by forming cascade energy levels; (3) improving hole mobilities of dopant-free o-HTLs by regulating their polymer/molecule orientation. What is more, the thermal/moisture/light stabilities of dopant-free o-HTLs-based PSCs were greatly improved with QD interlayers. Finally, we demonstrated the reliability of the QD interlayers by fabricating large-area solar modules with dopant-free o-HTLs, showing great potential in commercial usage.

An Organic-Inorganic Hybrid Electrolyte as a Cathode Interlayer for Efficient Organic Solar Cells.

An organic-inorganic hybrid electrolyte based on a cyclic Ti-oxo cluster as the inorganic core and naphthalene-based organic ammonium bromide salts as the electrolyte was developed with easy synthesis and low cost. The new hybrid electrolyte exhibits excellent solubility in methanol, aligned work function, good conductivity, and amorphous state in thin film, enabling its successful application as a cathode interlayer in organic solar cells with a high power conversion efficiency of 17.19 %. This work demonstrates that the hybrid electrolytes are a new kind of semiconductor, exhibiting promising applications in organic electronics.

Highly Anisotropic Corncob as an Efficient Solar Steam-Generation Device with Heat Localization and Rapid Water Transportation.

Solar steam generation is receiving considerable interest because of its potential application in wastewater treatment and desalination. Many devices with various photothermal materials and structures have been demonstrated to be solar steam evaporators by improving their light absorption, heat loss, water transportation, and vapor escape. However, developing a biomass-based evaporator with heat localization and rapid water transportation is highly desired yet still challenging. Here, corncobs, a kind of agricultural waste with vascular bundle and "vesiculose" structures, are used to fabricate solar steam-generation devices. After high-temperature treatment, the carbonized corncobs maintain the highly anisotropic porous framework and favorable hydrophilicity and thereby have excellent thermal management and water transportation. With efficient solar absorption, heat localization, and rapid water transportation, the lightweight carbonized corncobs can float on water and generate water vapor with a high steam generation efficiency of 86.7% under 1 sun.

Surface coordination layer passivates oxidation of copper.

Owing to its high thermal and electrical conductivities, its ductility and its overall non-toxicity1-3, copper is widely used in daily applications and in industry, particularly in anti-oxidation technologies. However, many widespread anti-oxidation techniques, such as alloying and electroplating1,2, often degrade some physical properties (for example, thermal and electrical conductivities and colour) and introduce harmful elements such as chromium and nickel. Although efforts have been made to develop surface passivation technologies using organic molecules, inorganic materials or carbon-based materials as oxidation inhibitors4-12, their large-scale application has had limited success. We have previously reported the solvothermal synthesis of highly air-stable copper nanosheets using formate as a reducing agent13. Here we report that a solvothermal treatment of copper in the presence of sodium formate leads to crystallographic reconstruction of the copper surface and formation of an ultrathin surface coordination layer. We reveal that the surface modification does not affect the electrical or thermal conductivities of the bulk copper, but introduces high oxidation resistance in air, salt spray and alkaline conditions. We also develop a rapid room-temperature electrochemical synthesis protocol, with the resulting materials demonstrating similarly strong passivation performance. We further improve the oxidation resistance of the copper surfaces by introducing alkanethiol ligands to coordinate with steps or defect sites that are not protected by the passivation layer. We demonstrate that the mild treatment conditions make this technology applicable to the preparation of air-stable copper materials in different forms, including foils, nanowires, nanoparticles and bulk pastes. We expect that the technology developed in this work will help to expand the industrial applications of copper.

Methylamine-Dimer-Induced Phase Transition toward MAPbI3 Films and High-Efficiency Perovskite Solar Modules.

Perovskite films prepared with CH3NH2 molecules under ambient conditions have led to rapid fabrication of perovskite solar cells (PSCs), but there remains a lack of mechanistic studies and inconsistencies with operability in their production. Here the crystal structure of CH3NH2-CH3NH3PbI3 was analyzed to involve hydrogen bonds (CH3NH2···CH3NH3+) and has guided the facile, reproducible preparation of high-quality perovskite films under ambient conditions. Hydrogen bonds within CH3NH2···CH3NH3+ dimers were found in the CH3NH2-CH3NH3PbI3 intermediates, accompanied by 1D-PbI3- chains (δ-phase). The weakly hydrogen-bonded CH3NH2 molecules were easily released from the CH3NH2-CH3NH3PbI3 intermediates, contributing to rapid, spontaneous phase transition from 1D-PbI3- (δ-phase) to 3D-PbI3- (α-phase). Further introduction of CH3NH3Cl into the CH3NH2-CH3NH3PbI3 intermediates led to interruption of 1D-PbI3- transition into 0D-Pb2I9-xClx5-(0 < x < 6), adjusting the phase transition route toward 3D-PbI3-. On the basis of the above understanding, CH3NH2 solution in ethanol and CH3NH3Cl were used for precursors and a best efficiency of 20.3% in PSCs was achieved. Large-scale modules (12 cm2 aperture area) fabricated by a dip-coating technology exhibited an efficiency up to 16.0% and outstanding stability over 10 000 s under continuous output. The developed preparation method of perovskite precursors and insightful research into the methylamine-dimer-induced phase transition mechanism have enabled the production of high-quality perovskite films with robust operability, showing great potential for large-scale commercialization.

Existence of Ligands within Sol-Gel-Derived ZnO Films and Their Effect on Perovskite Solar Cells.

The sol-gel (SG) method has been well-documented as one useful way to produce ZnO films as an excellent electron transport material (ETM) for efficient perovskite solar cells (PSCs). Generally, the precursor films containing zinc acetate dihydrate and a stabilizing ligand monoethanolamine (EA) were annealed to obtain ZnO films. A noteworthy issue is the commonly reported annealing temperature (Ta) in a wide range of 150-600 °C. In this work, we investigated the effect of the annealing temperature on the film composition and first confirmed the co-existence of acetate and EA species when Ta is below 380 °C. EA still survived within the ZnO films when Ta was between 380 and 450 °C. When Ta was over 450 °C, pure ZnO films can be obtained. The presence of ligands also remarkably altered the work function of the corresponding ZnO samples, thereby resulting in the remarkably different effects on the efficiency and stability of PSCs with the ZnO samples as ETMs. This work affords a clearer understanding of ZnO films prepared by the SG method at molecular insights, promoting their application in photoelectric fields.