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1.
Plant Signal Behav ; 19(1): 2335025, 2024 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-38678583

RESUMEN

Allelopathy is the main chemical means in the invasion process of exotic plants and one of the key factors in grassland degradation. In this experiment, we investigated the effects of ethyl acetate phase extract (EAE), n-butanol phase extract (BE) and aqueous phase extract (AE) from the aboveground (stems and leaves) and roots of Ligularia sagitta on seed germination and seedling growth of four Gramineae forages (Poa pratensis L. Festuca ovina L. Elymus nutans Griseb. Agropyron cristatum (L.) Gaertn.) in their sympatric domains and one Legosuminae forage (Medicago sativa L.). The chemical components in each phase extract of L. sagitta were determined with UHPLC-MS/MS non-targeted metabolomics, and the differential compounds were screened using Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA). Within a set concentration range, EAE significantly inhibited seed germination and seedling growth of four Gramineae forages. BE and AE acted mainly in the seedling growth stage and did not significantly inhibit forage seed germination. P. pratensis was most sensitive to L. sagitta extracts; at 2.0 mg/mL of EAE from roots, germination energy and germination rate of P. pratensis seeds were 0. L. sagitta extracts inhibited the growth of M. sativa seedlings and did not inhibit its seed germination. A total of 904 compounds were identified with UHPLC-MS/MS, among which 31, 64, 81 and 66 metabolites displayed different accumulation patterns in the four comparison groups (R.EAE vs. R.BE, R.EAE vs. R.AE, SL.EAE vs. SL.BE, SL.EAE vs. SL.AE), respectively. In particular, 9 compounds were found to be common up-regulated differential metabolites in the four comparison groups and were enriched in EAE. Additionally, N,N-dimethylaniline, Caffeic acid, 4-Hydroxybenzoic acid, 4-Hydroxybenzaldehyde and cis-9-Octadecenoic acid as potential allelochemicals in L. sagitta. The results of this study support efforts at finding alternative control plants for the restoration of poisonous grass-type degraded grasslands.


Asunto(s)
Alelopatía , Asteraceae , Germinación , Especies Introducidas , Feromonas , Asteraceae/metabolismo , Asteraceae/efectos de los fármacos , Feromonas/farmacología , Feromonas/metabolismo , Germinación/efectos de los fármacos , Plantones/efectos de los fármacos , Plantones/metabolismo , Plantones/crecimiento & desarrollo , Extractos Vegetales/farmacología
2.
Int J Biol Macromol ; 265(Pt 1): 130907, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38492707

RESUMEN

Traditional hot water reflux extraction, ultrasonic-water extraction (UW), ultrasonic-natural deep eutectic solvent (NADES) extraction (U-NADES), ultrasonic-water and enzyme extraction (U-W-E) and ultrasonic-NADES and enzyme extraction (U-NADES-E) are employed for the extraction of Rhizoma et Radix Notopterygii polysaccharides (RNP), in which, the U-NADES-E has being proved as the most effective method. Response Surface Methodology (RSM) was utilized to optimize the conditions for U-NADES-E method. Using the optimal extraction conditions, the yield of RNP can be enhanced by nearly two-fold in comparison to the traditional extraction method, achieving a yield of 7.38 %, with a mere 30-min treatment and low ultrasonic power at 240 W. The RNP's composition included Rhamnose, Arabinose, Galactose, Glucose and Galacturonic Acid by high-performance anion-exchange chromatography. The polysaccharides from two different species of Rhizoma et Radix Notopterygii have also been characterized and identified. Network pharmacology and molecular docking predict that RNP may exert its effects in vivo through binding to PPARA, ACE and REN proteins, thereby potentially impacting diabetes outcomes. This study proposes a new, efficient, energy-saving and environmentally-friendly method for the extraction of RNP.


Asunto(s)
Apiaceae , Simulación del Acoplamiento Molecular , Apiaceae/química , Rizoma/química , Solventes , Agua/análisis , Polisacáridos/química
3.
Nat Commun ; 15(1): 2579, 2024 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-38519495

RESUMEN

Perovskite photovoltaics, typically based on a solution-processed perovskite layer with a film thickness of a few hundred nanometres, have emerged as a leading thin-film photovoltaic technology. Nevertheless, many critical issues pose challenges to its commercialization progress, including industrial compatibility, stability, scalability and reliability. A thicker perovskite film on a scale of micrometres could mitigate these issues. However, the efficiencies of thick-film perovskite cells lag behind those with nanometre film thickness. With the mechanism remaining elusive, the community has long been under the impression that the limiting factor lies in the short carrier lifetime as a result of defects. Here, by constructing a perovskite system with extraordinarily long carrier lifetime, we rule out the restrictions of carrier lifetime on the device performance. Through this, we unveil the critical role of the ignored lattice strain in thick films. Our results provide insights into the factors limiting the performance of thick-film perovskite devices.

4.
Anal Chem ; 2024 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-38324760

RESUMEN

Molecular vibrational spectroscopies, including infrared absorption and Raman scattering, provide molecular fingerprint information and are powerful tools for qualitative and quantitative analysis. They benefit from the recent development of deep-learning-based algorithms to improve the spectral, spatial, and temporal resolutions. Although a variety of deep-learning-based algorithms, including those to simultaneously extract the global and local spectral features, have been developed for spectral classification, the classification accuracy is still far from satisfactory when the difference becomes very subtle. Here, we developed a lightweight algorithm named patch-based convolutional encoder (PACE), which effectively improved the accuracy of spectral classification by extracting spectral features while balancing local and global information. The local information was captured well by segmenting the spectrum into patches with an appropriate patch size. The global information was extracted by constructing the correlation between different patches with depthwise separable convolutions. In the five open-source spectral data sets, PACE achieved a state-of-the-art performance. The more difficult the classification, the better the performance of PACE, compared with that of residual neural network (ResNet), vision transformer (ViT), and other commonly used deep learning algorithms. PACE helped improve the accuracy to 92.1% in Raman identification of pathogen-derived extracellular vesicles at different physiological states, which is much better than those of ResNet (85.1%) and ViT (86.0%). In general, the precise recognition and extraction of subtle differences offered by PACE are expected to facilitate vibrational spectroscopy to be a powerful tool toward revealing the relevant chemical reaction mechanisms in surface science or realizing the early diagnosis in life science.

5.
Molecules ; 28(23)2023 Nov 29.
Artículo en Inglés | MEDLINE | ID: mdl-38067574

RESUMEN

In this study, an ultrasound-assisted green extraction method was applied for the extraction of polysaccharides from Radix Peucedani based on deep eutectic solvents (DESs), and the result showed that a DES system composed of betaine and 1,2-propylene glycol with a molar ratio of 1:2 possessed the optimal extraction efficiency for polysaccharides. Single-factor and Box-Behnken designs were used to determine the optimum extraction conditions for the maximum yields of polysaccharides from Radix Peucedani by using DESs. The maximum yields of polysaccharides attained 11.372% within a DES water content of 19%, an extraction time of 36 min, an extraction temperature of 54 °C, a solid-liquid ratio of 1:30 and an ultrasonic irradiation power of 420 W. The physicochemical properties of polysaccharides were analyzed using ICS and FT-IR, and the structure morphology was observed by SEM. The polysaccharides extracted from Radix Peucedani exhibited general antioxidant activities in vitro including DPPH, Hydroxyl and ABTS+ radical-scavenging activity. The antioxidant mechanism of Radix Peucedani polysaccharides was investigated using network pharmacology and molecular docking methods. The result showed that the high binding activity of glucose and IL1B, galactose and CASP3 was recognized as a potential mechanism for the antioxidant effects of Radix Peucedani polysaccharides.


Asunto(s)
Antioxidantes , Agua , Antioxidantes/farmacología , Antioxidantes/química , Espectroscopía Infrarroja por Transformada de Fourier , Simulación del Acoplamiento Molecular , Agua/química , Polisacáridos/farmacología , Polisacáridos/química
6.
Small ; 19(49): e2303255, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37606884

RESUMEN

Fluoro-substituted aromatic alkylammonium spacer cations are found effective to improve the performance of quasi-2D perovskite light-emitting diodes (PeLEDs). The fluorine substitution is generally attributed to the defect passivation, quantum well width control, and energy level adjustments. However, the substituted cations can also affect the crystallization process but is not thoroughly studied. Herein, a comparison study is carried out using bare PEA cation and three different fluoro-substituted PEA (x-F-PEA, x = o, ortho; m, meta; p, para) cations to investigate the impacts of different substitution sites on the perovskite crystallization and orientations. By using GIWAXS, p-F-PEA cation is found to induce the strongest preferential out-of-plane orientations with the best crystallinity in quasi-2D perovskite. Using dynamic light scattering (DLS) methods, larger colloidal particles (630 nm) are revealed in p-F-PEA precursor solutions than the PEA cations (350 nm). The larger particles can accelerate the crystallization process and induce out-of-plane orientation from increased dipole-dipole interaction. The transient absorption measurement confirms longer radiative recombination lifetime, proving beneficial effect of p-F-PEA cation. As a result, the fabricated p-F-PEA-based PeLEDs achieved the highest EQE of 15.2%, which is higher than those of PEA- (8.8%), o-F-PEA- (4.3%), and m-F-PEA-based (10.3%) PeLEDs.

7.
Nanomaterials (Basel) ; 13(13)2023 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-37446498

RESUMEN

Metal halide perovskite materials have demonstrated significant potential in various optoelectronic applications, such as photovoltaics, light emitting diodes, photodetectors, and lasers. However, the stability issues of perovskite materials continue to impede their widespread use. Many studies have attempted to understand the complex degradation mechanism and dynamics of these materials. Among them, in situ and/or operando approaches have provided remarkable insights into the degradation process by enabling precise control of degradation parameters and real-time monitoring. In this review, we focus on these studies utilizing in situ and operando approaches and demonstrate how these techniques have contributed to reveal degradation details, including structural, compositional, morphological, and other changes. We explore why these two approaches are necessary in the study of perovskite degradation and how they can be achieved by upgrading the corresponding ex situ techniques. With recent stability improvements of halide perovskite using various methods (compositional engineering, surface engineering, and structural engineering), the degradation of halide perovskite materials is greatly retarded. However, these improvements may turn into new challenges during the investigation into the retarded degradation process. Therefore, we also highlight the importance of enhancing the sensitivity and probing range of current in situ and operando approaches to address this issue. Finally, we identify the challenges and future directions of in situ and operando approaches in the stability research of halide perovskites. We believe that the advancement of in situ and operando techniques will be crucial in supporting the journey toward enhanced perovskite stability.

8.
Nanomicro Lett ; 15(1): 143, 2023 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-37266746

RESUMEN

The performance of proton exchange membrane fuel cells is heavily dependent on the microstructure of electrode catalyst especially at low catalyst loadings. This work shows a hybrid electrocatalyst consisting of PtNi-W alloy nanocrystals loaded on carbon surface with atomically dispersed W sites by a two-step straightforward method. Single-atomic W can be found on the carbon surface, which can form protonic acid sites and establish an extended proton transport network at the catalyst surface. When implemented in membrane electrode assembly as cathode at ultra-low loading of 0.05 mgPt cm-2, the peak power density of the cell is enhanced by 64.4% compared to that with the commercial Pt/C catalyst. The theoretical calculation suggests that the single-atomic W possesses a favorable energetics toward the formation of *OOH whereby the intermediates can be efficiently converted and further reduced to water, revealing a interfacial cascade catalysis facilitated by the single-atomic W. This work highlights a novel functional hybrid electrocatalyst design from the atomic level that enables to solve the bottle-neck issues at device level.

9.
Nanomicro Lett ; 15(1): 138, 2023 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-37245182

RESUMEN

Perovskite crystal facets greatly impact the performance and stability of their corresponding photovoltaic devices. Compared to the (001) facet, the (011) facet yields better photoelectric properties, including higher conductivity and enhanced charge carrier mobility. Thus, achieving (011) facet-exposed films is a promising way to improve device performance. However, the growth of (011) facets is energetically unfavorable in FAPbI3 perovskites due to the influence of methylammonium chloride additive. Here, 1-butyl-4-methylpyridinium chloride ([4MBP]Cl) was used to expose (011) facets. The [4MBP]+ cation selectively decreases the surface energy of the (011) facet enabling the growth of the (011) plane. The [4MBP]+ cation causes the perovskite nuclei to rotate by 45° such that (011) crystal facets stack along the out-of-plane direction. The (011) facet has excellent charge transport properties and can achieve better-matched energy level alignment. In addition, [4MBP]Cl increases the activation energy barrier for ion migration, suppressing decomposition of the perovskite. As a result, a small-size device (0.06 cm2) and a module (29.0 cm2) based on exposure of the (011) facet achieved power conversion efficiencies of 25.24% and 21.12%, respectively.

10.
Small ; 19(24): e2207817, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36919945

RESUMEN

Both the uncoordinated Pb2+ and excess PbI2 in perovskite film will create defects and perturb carrier collection, thus leading to the open-circuit voltage (VOC ) loss and inducing rapid performance degradation of perovskite solar cells (PSCs). Herein, an additive of 3-aminothiophene-2-carboxamide (3-AzTca) that contains amide and amino and features a large molecular size is introduced to improve the quality of perovskite film. The interplay of size effect and adequate bonding strength between 3-AzTca and uncoordinated Pb2+ regulates the mineralization of PbI2 and generates low-dimensional PbI2 phase, thereby boosting the crystallization of perovskite. The decreased defect states result in suppressed nonradiative recombination and reduced VOC loss. The power conversion efficiency (PCE) of modified PSC is improved to 22.79% with a high VOC of 1.22 V. Moreover, the decomposition of PbI2 and perovskite films is also retarded, yielding enhanced device stability. This study provides an effective method to minimize the concentration of uncoordinated Pb2+ and improve the PCE and stability of PSCs.

11.
Cancer Sci ; 114(5): 2109-2122, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-36625184

RESUMEN

Non-small-cell lung cancer (NSCLC) is one of the deadliest cancers worldwide, and metastasis is considered one of the leading causes of treatment failure in NSCLC. Wnt/ß-catenin signaling is crucially involved in epithelial-mesenchymal transition (EMT), a crucial factor in promoting metastasis, and also contributes to resistance developed by NSCLC to targeted agents. Frizzled-7 (Fzd7), a critical receptor of Wnt/ß-catenin signaling, is aberrantly expressed in NSCLC and has been confirmed to be positively correlated with poor clinical outcomes. SHH002-hu1, a humanized antibody targeting Fzd7, was previously successfully generated by our group. Here, we studied the anti-tumor effects of SHH002-hu1 against NSCLC and revealed the underlying mechanism. First, immunofluorescence (IF) and near-infrared (NIR) imaging assays showed that SHH002-hu1 specifically binds Fzd7+ NSCLC cells and targets NSCLC tissues. Wound healing and transwell invasion assays indicated that SHH002-hu1 significantly inhibits the migration and invasion of NSCLC cells. Subsequently, TOP-FLASH/FOP-FLASH luciferase reporter, IF, and western blot assays validated that SHH002-hu1 effectively suppresses the activation of Wnt/ß-catenin signaling, and further attenuates the EMT of NSCLC cells. Finally, the subcutaneous xenotransplanted tumor model of A549/H1975, as well as the popliteal lymph node (LN) metastasis model, was established, and SHH002-hu1 was demonstrated to inhibit the growth of NSCLC xenografts and suppress LN metastasis of NSCLC. Above all, SHH002-hu1 with selectivity toward Fzd7+ NSCLC and the potential of inhibiting invasion and metastasis of NSCLC via disrupting Wnt/ß-catenin signaling, is indicated as a good candidate for the targeted therapy of NSCLC.


Asunto(s)
Antineoplásicos , Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Humanos , Anticuerpos/farmacología , Antineoplásicos/farmacología , beta Catenina/genética , Carcinoma de Pulmón de Células no Pequeñas/genética , Línea Celular Tumoral , Movimiento Celular , Proliferación Celular , Transición Epitelial-Mesenquimal , Regulación Neoplásica de la Expresión Génica , Neoplasias Pulmonares/genética , Vía de Señalización Wnt
12.
Science ; 379(6630): 399-403, 2023 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-36701445

RESUMEN

Daily temperature variations induce phase transitions and lattice strains in halide perovskites, challenging their stability in solar cells. We stabilized the perovskite black phase and improved solar cell performance using the ordered dipolar structure of ß-poly(1,1-difluoroethylene) to control perovskite film crystallization and energy alignment. We demonstrated p-i-n perovskite solar cells with a record power conversion efficiency of 24.6% over 18 square millimeters and 23.1% over 1 square centimeter, which retained 96 and 88% of the efficiency after 1000 hours of 1-sun maximum power point tracking at 25° and 75°C, respectively. Devices under rapid thermal cycling between -60° and +80°C showed no sign of fatigue, demonstrating the impact of the ordered dipolar structure on the operational stability of perovskite solar cells.

13.
Int J Mol Sci ; 24(2)2023 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-36674721

RESUMEN

Klotho (KL) is a glycosyl hydrolase and aging-suppressor gene. Stress is a risk factor for depression and anxiety, which are highly comorbid with each other. The aim of this study is to determine whether KL is regulated by estrogen and plays an important role in sex differences in stress resilience. Our results showed that KL is regulated by estrogen in rat hippocampal neurons in vivo and in vitro and is essential for the estrogen-mediated increase in the number of presynaptic vesicular glutamate transporter 1 (Vglut1)-positive clusters on the dendrites of hippocampal neurons. The role of KL in sex differences in stress response was examined in rats using 3-week chronic unpredictable mild stress (CUMS). CUMS produced a deficit in spatial learning and memory, anhedonic-like behaviors, and anxiety-like behaviors in male but not female rats, which was accompanied by a reduction in KL protein levels in the hippocampus of male but not female rats. This demonstrated the resilience of female rats to CUMS. Interestingly, the knockdown of KL protein levels in the rat hippocampus of both sexes caused a decrease in stress resilience in both sexes, especially in female rats. These results suggest that the regulation of KL by estrogen plays an important role in estrogen-mediated synapse formation and that KL plays a critical role in the sex differences in cognitive deficit, anhedonic-like behaviors, and anxiety-like behaviors induced by chronic stress in rats, highlighting an important role of KL in sex differences in stress resilience.


Asunto(s)
Depresión , Caracteres Sexuales , Ratas , Animales , Masculino , Femenino , Depresión/metabolismo , Ansiedad , Trastornos de Ansiedad/metabolismo , Hipocampo/metabolismo , Estrés Psicológico/metabolismo , Modelos Animales de Enfermedad , Estrógenos/metabolismo
14.
Sci Total Environ ; 859(Pt 2): 160154, 2023 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-36375548

RESUMEN

In alpine systems, cushion plants act as foundation species by ameliorating local environmental conditions. Empirical studies indicate that contrasting phenotypes of alpine cushion species have different effects on understory plant species, either facilitative or competitive. Furthermore, dependent species within each community type might also exhibit different responses to each cushion phenotype, which can be clustered into several "response groups". Additionally, these species-groups specific responses to alpine cushion species phenotypes could alter community assembly. However, very few studies have assessed responses of dependent communities at species-group levels, in particular for both above- and below-ground communities. Here, we selected a loose and a tight phenotype of the alpine cushion species Thylacospermum caespitosum in two sites of northwest China, and use the relative intensity of interactions index to quantify cushion plant effects on subordinate communities of plants and soil fungi and bacteria. We assessed variations in responses of both above- and below-ground organisms to cushion plant effects at species-group level. Species-group level analyses showed that the effects of the phenotype varied among groups of each of the three community types, and different species-groups were composed by unique taxa. Additionally, we found that loose cushions enhanced stochastic processes in community assembly, for plants and soil fungi but not for soil bacteria. These variations of phenotypic effects on different species-group induced contrasting taxonomic composition between groups, and alter community assembly thereby. Our study highlights the occurrence of contrasting effects of two phenotypes of a foundation cushion plant on understory plants, soil fungi and bacteria community composition, but not necessarily on their richness. We also showed that assessing responses of understory species at the species-group level allows a more realistic and mechanistic understanding of biotic interactions both for above- and below-ground communities.


Asunto(s)
Caryophyllaceae , Plantas , Caryophyllaceae/fisiología , Suelo , Fenotipo , China , Ecosistema
15.
Materials (Basel) ; 15(24)2022 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-36556552

RESUMEN

Fused deposition modeling (FDM) technique is one of the most popular additive manufacturing techniques. Infill density is a critical factor influencing the mechanical properties of 3D-printed components using the FDM technique. For irregular components with variable cross-sections, to increase their overall mechanical properties while maintaining a lightweight, it is necessary to enhance the local infill density of the thin part while decreasing the infill density of the thick part. However, most current slicing software can only generate a uniform infill throughout one model to be printed and cannot adaptively create a filling structure with a varying infill density according to the dimensional variation of the cross-section. In the present study, to improve the mechanical properties of irregular components with variable cross-sections, an adaptive-density filling structure was proposed, in which Hilbert curve with the same order was used to fill each slice, i.e., the level of the Hilbert curves in each slice is the same, but the side length of the Hilbert curve decreases with the decreasing size of each slice; hence, the infill density of the smaller cross-section is greater than that of the larger cross-section. The ultimate bearing capacity of printed specimens with the adaptive-density filling structure was evaluated by quasi-static compression, three-point bending, and dynamic compression tests, and the printed specimens with uniform filling structure and the same overall infill density were tested for comparison. The results show that the maximum flexural load, the ultimate compression load, and the maximum impact resistance of the printed specimens with the adaptive-density filling structure were increased by 140%, 47%, and 82%, respectively, compared with their counterparts using the uniform filling structure.

16.
Science ; 378(6621): 747-754, 2022 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-36395230

RESUMEN

The mixtures of cations and anions used in hybrid halide perovskites for high-performance solar cells often undergo element and phase segregation, which limits device lifetime. We adapted Schelling's model of segregation to study individual cation migration and found that the initial film inhomogeneity accelerates materials degradation. We fabricated perovskite films (FA1-xCsxPbI3; where FA is formamidinium) through the addition of selenophene, which led to homogeneous cation distribution that retarded cation aggregation during materials processing and device operation. The resultant devices achieved enhanced efficiency and retained >91% of their initial efficiency after 3190 hours at the maximum power point under 1 sun illumination. We also observe prolonged operational lifetime in devices with initially homogeneous FACsPb(Br0.13I0.87)3 absorbers.

17.
J Am Chem Soc ; 144(40): 18470-18478, 2022 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-36164747

RESUMEN

Despite recent encouraging developments, achieving efficient blue perovskite light-emitting diodes (PeLEDs) have been widely considered a critical challenge. The efficiency breakthrough only occurred in the sky-blue region, and the device performance of pure-blue and deep-blue PeLEDs lags far behind those of their sky-blue counterparts. To avoid the negative effects associated with dimensionality reduction and excess chloride typically needed to achieve deep-blue emission, here we demonstrate guanidine (GA+)-induced deep-blue (∼457 nm) perovskite emitters enabling spectrally stable PeLEDs with a record external quantum efficiency (EQE) over 3.41% through a combination of quasi-2D perovskites and halide engineering. Owing to the presence of GA+, even a small inclusion of chloride ions is sufficient for generating deep-blue electroluminescence (EL), in clear contrast to the previously reported deep-blue PeLEDs with significant chloride inclusion that negatively affects spectral stability. Based on the carrier dynamics analysis and theoretical calculation, GA+ is found to stabilize the low-dimensional species during annealing, retarding the cascade energy transfer and facilitating the deep-blue EL. Our findings open a potential third route to achieve deep-blue PeLEDs beyond the conventional methods of dimensionality reduction and excessive chloride incorporation.

18.
Angew Chem Int Ed Engl ; 61(27): e202204314, 2022 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-35412681

RESUMEN

Perovskite solar cells (PSCs) have become a promising candidate for the next-generation photovoltaic technologies. As an essential element for high-efficiency PSCs however, the heavy metal Pb is soluble in water, causing a serious threat to the environment and human health. Due to the weak ionic bonding in three-dimensional (3D) perovskites, drastic structure decomposition occurs when immersing the perovskite film in water, which accelerates the Pb leakage. By introducing the chemically stable Dion-Jacobson (DJ) 2D perovskite at the 3D perovskite surface, the film dissolution is significantly slowed down, which retards lead leakage. As a result, the Pb contamination is dramatically reduced under various extreme conditions. In addition, the PSCs device deliver a power conversion efficiency (PCE) of 23.6 % and retain over 95 % of their initial PCE after the maximum power point tracking for over 1100 h.

19.
Small ; 17(33): e2100972, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34254433

RESUMEN

Quasi-2D perovskites are enchanting alternative materials for solar cells due to their intrinsic stability. The manipulation of crystal orientation of quasi-2D perovskites is indispensable to target efficient devices, however, the origin of orientation during the film fabrication process still lacks in-depth understanding and convincing evidence yet, which hinders further boosting the performance of photovoltaic devices. Herein, the crystallizing processes during spin-coating and annealing are probed by in situ grazing-incidence wide-angle X-ray scattering (GIWAXS), and the incident-angle-dependent GIWAXS is conducted to unveil the phase distribution in the films. It is found that undesirable lead iodide sol-gel formed intermediate phase would disturb oriented crystalline growth, resulting in random crystal orientation in poor quasi-2D films. A general strategy is developed via simple additive agent incorporation to suppress the formation of the intermediate phase. Accordingly, highly oriented perovskite films with reduced trap density and higher carrier mobility are obtained, which enables the demonstration of optimized quasi-2D perovskite solar cells with a power conversion efficiency of 15.2% as well as improved stability. This work paves a promising way to manipulate the quasi-2D perovskites nucleation and crystallization processes via tuning nucleation stage.

20.
ACS Appl Mater Interfaces ; 13(21): 24692-24701, 2021 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-34008958

RESUMEN

Excess lead iodide (PbI2) plays a crucial role in passivating the defects of perovskite films and boosting the power conversion efficiency (PCE) of perovskite solar cells (PSCs). However, the photolysis of PbI2 is easily triggered by light illumination, which accelerates the decomposition of perovskite materials and weakens the long-term stability of PSCs. Herein, the high light tolerance of lead iodide (PbI2) is reported by introducing an electron-donor molecule, namely, 2-thiophenecarboxamide (2-TCAm), to strengthen the [PbX6]4- frame. Characterization reveals that the retarded decomposition of PbI2 is attributed to the interactions between Pb2+ and the organic functional groups in 2-TCAm as well as the optimized distribution of PbI2. The crystallization and morphology of 2-TCAm-doped perovskite films are improved simultaneously. The 2-TCAm-based PSCs achieve a 16.8% increase in PCE and nearly 12 times increase in the lifetime as compared to the reference device. The demonstrated method provides insight into the stability of PbI2 and its influence on PSCs.

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