| 1. |
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| 2. |
- Liu, Zhigang, et al.
(författare)
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Gut microbiota mediates intermittent-fasting alleviation of diabetes-induced cognitive impairment
- 2020
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 11:1, s. 855-
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Tidskriftsartikel (refereegranskat)abstract
- Cognitive decline is one of the complications of type 2 diabetes (T2D). Intermittent fasting (IF) is a promising dietary intervention for alleviating T2D symptoms, but its protective effect on diabetes-driven cognitive dysfunction remains elusive. Here, we find that a 28-day IF regimen for diabetic mice improves behavioral impairment via a microbiota-metabolites-brain axis: IF enhances mitochondrial biogenesis and energy metabolism gene expression in hippocampus, re-structures the gut microbiota, and improves microbial metabolites that are related to cognitive function. Moreover, strong connections are observed between IF affected genes, microbiota and metabolites, as assessed by integrative modelling. Removing gut microbiota with antibiotics partly abolishes the neuroprotective effects of IF. Administration of 3-indolepropionic acid, serotonin, short chain fatty acids or tauroursodeoxycholic acid shows a similar effect to IF in terms of improving cognitive function. Together, our study purports the microbiota-metabolites-brain axis as a mechanism that can enable therapeutic strategies against metabolism-implicated cognitive pathophysiologies.
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| 3. |
- Abbafati, Cristiana, et al.
(författare)
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- 2020
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Guo, Jiawei, et al.
(författare)
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Bimetallic Sulfides with Vacancy Modulation Exhibit Enhanced Electrochemical Performance
- 2024
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Ingår i: Advanced Functional Materials. - 1616-3028 .- 1616-301X. ; 34:28
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Tidskriftsartikel (refereegranskat)abstract
- Transition bimetallic sulfides show significant promise for energy-related applications because of their plentiful active sites and synergistic redox activity. However, limited pore size and low-conductivity issues hinder their application. The structure of NiCo-S with rich sulfur vacancies is first predicted by density functional theory (DFT) calculations. Different sulfur vacancy concentrations are modeled by DFT calculations, and the results confirm that sulfur vacancies enhance the conductivity of the electrode material and are more beneficial for the adsorption of OH* species. It is verified by the differential charge density that the electric field formed on the surface of the electrode can lead to strong interfacial interactions by electron aggregation, which promotes electron/ion transfer kinetics. Furthermore, NiCo-S nanosheets are prepared on carbon cloth enriched with different concentrations of sulfur vacancies (denoted as NiCo-Sv-x, with x representing the concentration of sulfur vacancies) by sulfide etching NiCo-MOF and annealing under H2/Ar atmosphere. The NiCo-Sv-x electrodes obtained are applied to the cathode of supercapacitors and the anode of the oxygen evolution reaction. Through combining experimental and theoretical analysis, the effect of vacancy defect engineering on the electrochemical performance of the electrode materials is further confirmed. This work constructs transition metal sulfides with different sulfur vacancy concentrations through DFT model prediction and experimental validation, further confirming the effect of vacancy defect engineering on the electrochemical performance of electrode materials. Therefore, this modulation of sulfur vacancy concentration by vacancy defects contributes to the construction of electrode materials with excellent performance for energy applications.
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| 5. |
- Wang, Binmin, et al.
(författare)
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Multifunctional Underwater Adhesive Film Enabled by a Single-Component Poly(ionic liquid)
- 2023
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 17:6, s. 5871-5879
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Tidskriftsartikel (refereegranskat)abstract
- Tremendous efforts have been devoted to exploiting synthetic wet adhesives for real-life applications. However, developing low-cost, robust, and multifunctional wet adhesive materials remains a considerable challenge. Herein, a wet adhesive composed of a single-component poly(ionic liquid) (PIL) that enables fast and robust underwater adhesion is reported. The PIL adhesive film possesses excellent stretchability and flexibility, enabling its anchoring on target substrates regardless of deformation and water scouring. Surface force measurements show the PIL can achieve a maximum adhesion of 56.7 mN·m–1 on diverse substrates (both hydrophilic and hydrophobic substrates) in aqueous media, within ∼30 s after being applied. The adhesion mechanisms of the PIL were revealed via the force measurements, and its robust wet adhesive capacity was ascribed to the synergy of different non-covalent interactions, such as of hydrogen bonding, cation−π, electrostatic, and van der Waals interactions. Surprisingly, this PIL adhesive film exhibited impressive underwater sound absorption capacity. The absorption coefficient of a 0.7 mm-thick PIL film to 4–30 kHz sound waves could be as high as 0.80–0.92. This work reports a multifunctional PIL wet adhesive that has promising applications in many areas and provides deep insights into interfacial interaction mechanisms underlying the wet adhesion capability of PILs.
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| 6. |
- Li, Peibo, et al.
(författare)
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Three-dimensional flow structures and droplet-gas mixing process of a liquid jet in supersonic crossflow
- 2019
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Ingår i: Aerospace Science and Technology. - : Elsevier BV. - 1270-9638. ; 90, s. 140-156
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Tidskriftsartikel (refereegranskat)abstract
- The mixing process of a liquid jet in supersonic crossflow with a Mach number of 2.1 was investigated numerically using large eddy simulation (LES) based on the Eulerian-Lagrangian method. The gas phase was described using the Navier-Stokes equations and the liquid phase was represented using discrete droplets, which were injected and tracked in the computational domain individually according to Newton's second law of motion. The KH (Kelvin-Helmholtz) breakup model was used to calculate the droplet stripping process, and the secondary breakup process was simulated by coupling the RT (Rayleigh-Taylor) breakup model and the TAB (Taylor Analogy Breakup) model. Two-way coupling was enforced to consider the momentum and energy exchange between the gas and the droplets. It was found that the LES predicted spray characteristics, including spray penetration and cross-sectional distribution, agree reasonably well with the experiment. The major gas flow structures such as the bow shock, the large-scale vortices, and the recirculation zones were replicated successfully in the simulations. It was found that the gas flow structures have a significant effect on the mixing process of the droplets. The simulation results revealed that two sets of counter-rotating vortex pair (CVP) exist in the gas-liquid mixing region. Under the influence of CVP, part droplets were transported to the near wall region and subsequently to both sides of the core spray region. The formation mechanism of the CVP was analyzed by comparing the pressure gradient and the source term of droplets in the Navier-Stokes equations. Differences of the mixing process of liquid jet in supersonic crossflow, gas jet in supersonic crossflow and liquid jet in incompressible crossflow were identified.
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| 7. |
- Shi, Weibo, et al.
(författare)
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Optimizing Observation Plans for Identifying Faxon Fir (Abies fargesii var. Faxoniana) Using Monthly Unmanned Aerial Vehicle Imagery
- 2023
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Ingår i: Remote Sensing. - 2072-4292. ; 15:8
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Tidskriftsartikel (refereegranskat)abstract
- Faxon fir (Abies fargesii var. faxoniana), as a dominant tree species in the subalpine coniferous forest of Southwest China, has strict requirements regarding the temperature and humidity of the growing environment. Therefore, the dynamic and continuous monitoring of Faxon fir distribution is very important to protect this highly sensitive ecological environment. Here, we combined unmanned aerial vehicle (UAV) imagery and convolutional neural networks (CNNs) to identify Faxon fir and explored the identification capabilities of multispectral (five bands) and red-green-blue (RGB) imagery under different months. For a case study area in Wanglang Nature Reserve, Southwest China, we acquired monthly RGB and multispectral images on six occasions over the growing season. We found that the accuracy of RGB imagery varied considerably (the highest intersection over union (IoU), 83.72%, was in April and the lowest, 76.81%, was in June), while the accuracy of multispectral imagery was consistently high (IoU > 81%). In April and October, the accuracy of the RGB imagery was slightly higher than that of multispectral imagery, but for the other months, multispectral imagery was more accurate (IoU was nearly 6% higher than those of the RGB imagery for June). Adding vegetation indices (VIs) improved the accuracy of the RGB models during summer, but there was still a gap to the multispectral model. Hence, our results indicate that the optimized time of the year for identifying Faxon fir using UAV imagery is during the peak of the growing season when using a multispectral imagery. During the non-growing season, RGB imagery was no worse or even slightly better than multispectral imagery for Faxon fir identification. Our study can provide guidance for optimizing observation plans regarding data collection time and UAV loads and could further help enhance the utility of UAVs in forestry and ecological research.
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| 8. |
- Wu, Jinshui, et al.
(författare)
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The hybrid RANS/LES of partially premixed supersonic combustion using G/Z flamelet model
- 2016
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Ingår i: Acta Astronautica. - : Elsevier BV. - 0094-5765. ; 127, s. 375-383
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Tidskriftsartikel (refereegranskat)abstract
- In order to describe partially premixed supersonic combustion numerically, G/Z flamelet model is developed and compared with finite rate model in hybrid RANS/LES simulation to study the strut-injection supersonic combustion flow field designed by the German Aerospace Center. A new temperature calculation method based on time-splitting method of total energy is introduced in G/Z flamelet model. Simulation results show that temperature predictions in partially premixed zone by G/Z flamelet model are more consistent with experiment than finite rate model. It is worth mentioning that low temperature reaction zone behind the strut is well reproduced. Other quantities such as average velocity and average velocity fluctuation obtained by developed G/Z flamelet model are also in good agreement with experiment. Besides, simulation results by G/Z flamelet also reveal the mechanism of partially premixed supersonic combustion by the analyses of the interaction between turbulent burning velocity and flow field.
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| 9. |
- Zhang, Zhisen, et al.
(författare)
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Effects of Graphene Nanopore Geometry on DNA Sequencing
- 2014
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Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 5:9, s. 1602-1607
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Tidskriftsartikel (refereegranskat)abstract
- In this Letter we assess the effect of graphene nanopore geometries on DNA sequencing by considering DNA fragments including A, T, C, G, and 5-methylcytosine (MC) pulled out of graphene nanopores of different geometries with diameters down to similar to 1 nm. Using steered molecular dynamics simulations it is demonstrated that the bases (A, T, C, G, and MC) can be indentified at single-base resolution through the characteristic peaks on the force profile in a circular graphene nanopore but not in nanopores with other asymmetric geometries. Our study suggests that the graphene nanopore surface should be modified as symmetrically as possible in order to sequence DNA by atomic force microscopy or optical tweezers.
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| 10. |
- Duan, Hongbo, et al.
(författare)
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China’s adaptive response to climate change through air-conditioning
- 2023
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Ingår i: iScience. - : Elsevier BV. - 2589-0042. ; 26:3, s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- Studies have shown that the soaring demand for air conditioners in recent years is closely related to the worsening global warming; however, little evidence has been provided for China. This study uses weekly data of 343 Chinese cities to investigate how air conditioner sales respond to climate variability. We detected a U-shaped relationship between air-conditioning and temperature. An additional day with average temperature above 30°C increases weekly sales by 16.2%. Heterogeneity analysis shows that the adoption of air-conditioning is different for south and north China. By combining our estimates with shared socioeconomic pathway scenarios, we project China’s mid-century air conditioner sales and the resulting electricity demand. Under the fossil-fueled development scenario, air conditioner sales in the Pearl River Delta would rise by 71% (65.7%–87.6%) in summer. On average, the per capita electricity demand for air-conditioning will surge by 28% (23.2%–35.4%) in China by mid-century.
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| 11. |
- Hu, Hongbo, et al.
(författare)
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Otud7b facilitates T cell activation and inflammatory responses by regulating Zap70 ubiquitination
- 2016
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Ingår i: Journal of Experimental Medicine. - : ROCKEFELLER UNIV PRESS. - 0022-1007 .- 1540-9538. ; 213:3, s. 399-414
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Tidskriftsartikel (refereegranskat)abstract
- Signal transduction from the T cell receptor (TCR) is crucial for T cell-mediated immune responses and, when deregulated, also contributes to the development of autoimmunity. How TCR signaling is regulated is incompletely understood. In this study, we demonstrate a ubiquitin-dependent mechanism in which the deubiquitinase Otud7b has a crucial role in facilitating TCR signaling. Upon TCR ligation, Otud7b is rapidly recruited to the tyrosine kinase Zap70, a central mediator of TCR-proximal signaling. Otud7b deficiency attenuates the activation of Zap70 and its downstream pathways and impairs T cell activation and differentiation, rendering mice refractory to T cell-mediated autoimmune and inflammatory responses. Otud7b facilitated Zap70 activation by deubiquitinating Zap70, thus preventing the association of Zap70 with the negative-regulatory phosphatases Sts1 and Sts2. These findings establish Otud7b as a positive regulator of TCR-proximal signaling and T cell activation, highlighting the importance of deubiquitination in regulating Zap70 function.
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| 12. |
- Li, Danqin, et al.
(författare)
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n-Doping of photoactive layer in binary organic solar cells realizes over 18.3% efficiency
- 2022
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Ingår i: Nano Energy. - : ELSEVIER. - 2211-2855 .- 2211-3282. ; 96
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Tidskriftsartikel (refereegranskat)abstract
- Electronic doping of conjugated semiconductor plays a critical role in the fabrication of high efficiency organic optoelectronic devices. Here, we report an organic solar cell (OSC) by doping n-type DMBI-BDZC into one host binary bulk heterojunction (BHJ) photoactive layer comprised of a polymer donor PM6 and a nonfullerene acceptor Y6. The resulting champion device yields a significantly improved power conversion efficiency from 17.17% to 18.33% with an impressive fill factor of 80.20%. It is found that the electrically doped photoactive layer exhibits enhanced and balanced charge carrier mobilities, more effective exciton dissociation, longer carrier lifetime, and suppressed charge recombination with smaller energy loss. The dopant molecule DMBIBDZC also act as a surface morphology modifier of the photoactive layer with enhanced charge transport. This work demonstrates that manipulation of charge transport via adding a low concentration dopant into photoactive layer is a promising approach for further improvement of BHJ OSC performance.
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| 13. |
- Liang, Lijun, et al.
(författare)
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Theoretical Evaluation on Potential Cytotoxicity of Graphene Quantum Dots
- 2016
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Ingår i: ACS Biomaterials Science & Engineering. - : AMER CHEMICAL SOC. - 2373-9878. ; 2:11, s. 1983-1991
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Tidskriftsartikel (refereegranskat)abstract
- Owing to unique morphology, ultrasmall lateral sizes, and exceptional properties, graphene quantum dots (GQDs) hold great potential in many applications, especially in the field of electrochemical biosensors, bioimaging, drug delivery, et cetera. Its biosafety and potential cytotoxicity to human and animal cells has been a growing concern in recent years. In this work, the potential cytotoxicity of GQDs was evaluated by molecular dynamics simulations. Our simulation demonstrates that small size GQDs could easily permeate into the lipid membrane in a vertical way. It is relatively difficult to permeate into the lipid membrane for GQDs that are larger than GQD61 on the nanosecond time-scale. The thickness of the POPC membrane could even be affected by the small size of GQDs. Free energy calculations revealed that the free energy barrier of GQD permeation through the lipid membrane could greatly change with the change of GQD size. Under high GQD concentration, the GQD molecules could rapidly aggregate in water but disaggregate after entering into the membrane interior. Moreover, high concentrations of GQDs could induce changes in the structure properties and diffusion properties of the lipid bilayer, and it may affect the cell signal transduction. However, GQDs with relatively small size are not large enough to mechanically damage the lipid membrane. Our results suggest that the cytotoxicity of GQDs with small size is low and may be appropriate for biomedical application.
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| 14. |
- Lin, Baojun, et al.
(författare)
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Balancing the pre-aggregation and crystallization kinetics enables high efficiency slot-die coated organic solar cells with reduced non-radiative recombination losses
- 2020
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 13:8, s. 2467-2479
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Tidskriftsartikel (refereegranskat)abstract
- Slot-die coating being compatible with the roll-to-roll technique has been regarded as a promising tool for upscaling the manufacturing of organic solar cells (OSCs). However, there has been a significant gap between the efficiencies of the state-of-the-art spin-coated devices and the scalable processed devices. The active layer morphology is crucial to achieve high efficiency in OSCs, which depends on the conditions of film fabrication. To figure out and optimize the slot-die coating process, a deeper understanding of the film formation kinetics is important. Herein, in situ measurements of the slot-die coating process based on the PM7:IT4F system are demonstrated to illustrate the aggregation and crystallization evolution at various die temperatures and substrate temperatures. OSCs with a high power conversion efficiency of 13.2% are achieved at 60 degrees C die temperature/60 degrees C substrate temperature due to the improved exciton dissociation, charge transport and suppressed non-radiative charge recombination. The optimized morphology is attributed to the balanced polymer pre-aggregation and small molecule crystallization kinetics. The unsuitable die temperature leads to overlarge phase separation and consequently inefficient exciton dissociation while the improper substrate temperature results in weak crystallization and the following shrunken carrier lifetime with strong non-radiative combination. This work provides fundamental understanding on the correlations among processing methodology, solution pre-aggregation, morphology formation kinetics, device physics and device performance and affords guidance for device optimization in scalable manufacturing.
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| 15. |
- Zhang, Guoqing, et al.
(författare)
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Extensive and drastically different alpine lake changes on Asia's high plateaus during the past four decades
- 2017
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Ingår i: Geophysical Research Letters. - 0094-8276. ; 44:1, s. 252-260
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Tidskriftsartikel (refereegranskat)abstract
- Asia's high plateaus are sensitive to climate change and have been experiencing rapid warming over the past few decades. We found 99 new lakes and extensive lake expansion on the Tibetan Plateau during the last four decades, 1970–2013, due to increased precipitation and cryospheric contributions to its water balance. This contrasts with disappearing lakes and drastic shrinkage of lake areas on the adjacent Mongolian Plateau: 208 lakes disappeared and 75% of the remaining lakes have shrunk. We detected a statistically significant coincidental timing of lake area changes in both plateaus, associated with the climate regime shift that occurred during 1997/1998. This distinct change in 1997/1998 is thought to be driven by large-scale atmospheric circulation changes in response to climate warming. Our findings reveal that these two adjacent plateaus have been changing in opposite directions in response to climate change. These findings shed light on the complex role of the regional climate and water cycles, and provide useful information for ecological and water resource planning in these fragile landscapes.
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| 16. |
- Zhou, Wencai, et al.
(författare)
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The Role of Grain Boundaries on Ion Migration and Charge Recombination in Halide Perovskites
- 2024
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Ingår i: Small. - : WILEY-V C H VERLAG GMBH. - 1613-6810 .- 1613-6829.
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Tidskriftsartikel (refereegranskat)abstract
- Grain boundaries (GBs) have a significant role in polycrystalline perovskite solar cells (PSCs). However, there is ongoing debate regarding the impact of GBs on the performance and long-term stability of PSCs. Employing the first-principles molecular dynamics for perovskites, the iodine vacancy defect migrations both in bulk and at GBs are investigated. i) The positive iodine vacancy (VI+) is found that have both lower formation energy (1.4 eV) and activation energy (0.18 eV) than those of neutral iodine vacancy (VI), statistically. It indicated the VI+ acts as the dominant migrated iodine vacancy rather than VI; ii) the iodine vacancy at GBs has approximate to 0.48 eV higher activation energy than those in bulk, which leads to the accumulation of iodine vacancy at GBs; iii) the presence of VI+ result in a 3-fold increase in charge recombination ratio at GBs, compared to pristine PSCs. Based on quantum molecular dynamics statistical results, which are consistent with experimental measurements, insights into iodine vacancy migration both at GBs and in the bulk are gained. This understanding can be valuable for defects engineering related to ion migration, in order to improve the long-term stability and promote the performance of PSCs. Understanding defects engineering related to ion migration is crucial for enhancing the long-term stability and performance of hybrid perovskite solar cells. Iodine vacancies accumulate at grain boundaries due to lower formation energy and higher migration potential barrier compared to those in the bulk, which further increase the nonradiative recombination. image
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