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1.
Science ; 383(6688): 1198-1204, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38484055

RESUMO

Printable mesoscopic perovskite solar cells (p-MPSCs) do not require the added hole-transport layer needed in traditional p-n junctions but have also exhibited lower power conversion efficiencies of about 19%. We performed device simulation and carrier dynamics analysis to design a p-MPSC with mesoporous layers of semiconducting titanium dioxide, insulating zirconium dioxide, and conducting carbon infiltrated with perovskite that enabled three-dimensional injection of photoexcited electrons into titanium dioxide for collection at a transparent conductor layer. Holes underwent long-distance diffusion toward the carbon back electrode, and this carrier separation reduced recombination at the back contact. Nonradiative recombination at the bulk titanium dioxide/perovskite interface was reduced by ammonium phosphate modification. The resulting p-MPSCs achieved a power conversion efficiency of 22.2% and maintained 97% of their initial efficiency after 750 hours of maximum power point tracking at 55 ± 5°C.

2.
ACS Appl Mater Interfaces ; 16(1): 476-484, 2024 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-38155099

RESUMO

Antisolvent engineering is routinely used to modulate the crystallization of perovskite films as they can offer an additional driving force for nucleation. Actually, the intervention of antisolvent into nucleation is thought to involve some relatively fast and complex processes, which, however, are not fully understood so far. Here, the diffusion of the organic amine cation FA+ (one dominated precursor) and its distribution in a spin-coating process in different antisolvents is simulated by the computational fluid dynamics (CFD) model. It is suggested that a moderate diffusion rate (like that in the case of toluene as an antisolvent) not only enables to form a very uniform distribution of FA+ ions on the substrate, beneficial to the uniform nucleation of the intermediate phase, but also can balance the nucleation and growth rates of the intermediate phase, thereby suppressing undesired heterogeneous nucleation and growth. Results show that the perovskite film fabricated using toluene as an antisolvent has a high quality, based on which higher power conversion efficiencies of up to 24.32% are achieved for perovskite solar cells.

3.
ACS Nano ; 17(23): 23671-23678, 2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-37975813

RESUMO

The dynamic crystal lattice of halide perovskites facilitates the coupled transport of ions and electrons, offering innovative concepts in semiconductor iontronic devices that surpass solar cell applications. However, a comprehensive understanding of the intricacies of coupled ionic and electronic transport at the microscale remains ambiguous, owing to the inhomogeneity in ploy-crystalline perovskite thin films. In this work, we employed one-dimensional (1D) single-crystalline CsPbBr3 nanowires (NWs) to investigate the electric field induced ionic transport. Upon poling by an external bias, the previously uniform NW exhibits highly anisotropic ionic transport, which is identified as the origin of the giant switchable photovoltaic effect by spatially resolved scanning photocurrent microscopy. The subsequent ultrafast scanning photoluminescence (PL) microscopy measurements demonstrate significant localization of photocarriers near one terminal of the device, which is attributed to the accumulation of halogen vacancies. In addition, thanks to the enhancement of the local electric field, the poled device shows a 10-fold increase of photoresponse speed. Our findings favor the scale-down of perovskite devices to the submicrometer scale, extending their applications in self-powered iontronic and optoelectronic devices.

4.
Angew Chem Int Ed Engl ; 62(45): e202313133, 2023 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-37735100

RESUMO

Introducing fluorine (F) groups into a passivator plays an important role in enhancing the defect passivation effect for the perovskite film, which is usually attributed to the direct interaction of F and defect states. However, the interaction between electronegative F and electron-rich passivation groups in the same molecule, which may influence the passivation effect, is ignored. We herein report that such interactions can vary the electron cloud distribution around the passivation groups and thus changing their coordination with defect sites. By comparing two fluorinated molecules, heptafluorobutylamine (HFBM) and heptafluorobutyric acid (HFBA), we find that the F/-NH2 interaction in HFBM is stronger than the F/-COOH one in HFBA, inducing weaker passivation ability of HFBM than HFBA. Accordingly, HFBA-based perovskite solar cells (PSCs) provide an efficiency of 24.70 % with excellent long-term stability. Moreover, the efficiency of a large-area perovskite module (14.0 cm2 ) based on HFBA reaches 21.13 %. Our work offers an insight into understanding an unaware role of the F group in impacting the passivation effect for the perovskite film.

5.
Angew Chem Int Ed Engl ; 62(37): e202304494, 2023 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-37464980

RESUMO

Low-dimensional (low-D) organic metal halide hybrids (OMHHs) have emerged as fascinating candidates for optoelectronics due to their integrated properties from both organic and inorganic components. However, for most of low-D OMHHs, especially the zero-D (0D) compounds, the inferior electronic coupling between organic ligands and inorganic metal halides prevents efficient charge transfer at the hybrid interfaces and thus limits their further tunability of optical and electronic properties. Here, using pressure to regulate the interfacial interactions, efficient charge transfer from organic ligands to metal halides is achieved, which leads to a near-unity photoluminescence quantum yield (PLQY) at around 6.0 GPa in a 0D OMHH, [(C6 H5 )4 P]2 SbCl5 . In situ experimental characterizations and theoretical simulations reveal that the pressure-induced electronic coupling between the lone-pair electrons of Sb3+ and the π electrons of benzene ring (lp-π interaction) serves as an unexpected "bridge" for the charge transfer. Our work opens a versatile strategy for the new materials design by manipulating the lp-π interactions in organic-inorganic hybrid systems.

6.
ACS Appl Mater Interfaces ; 15(28): 33703-33711, 2023 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-37424078

RESUMO

As promising cathode candidates with advantageous capacity and price superiority for lithium-ion batteries, Ni-rich materials are severely impeded in the practical application due to their poor microstructural stability induced by the intrinsic Li+/Ni2+ cation mixing and mechanical stress accumulation upon cycling. In this work, a synergetic approach is demonstrated to improve the microstructural and thermal stabilities of Ni-rich LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode material through taking advantage of the thermal expansion offset effect of the LiZr2(PO4)3 (LZPO) modification layer. The optimized NCM622@LZPO cathode exhibits a significantly enhanced cyclability with a capacity retention of 67.7% after 500 cycles at 0.2 C and delivers a specific capacity of 115 mAh g-1 with a capacity retention of 64.2% after 300 cycles under 55 °C. Exploiting the chemical environment analysis of the Ni element detected by the synchrotron radiation technique, it is found that the mixing degree of Li+/Ni2+ cations in the bulk Ni-rich material can be effectively depressed through interfacial Zr4+ doping during the preparation of the LZPO-modified material. Additionally, time- and temperature-dependent powder diffraction spectra were collected to monitor the structure evolutions of pristine NCM622 and NCM622@LZPO cathodes in the initial cycles and under various temperatures, revealing the contribution of negative thermal expansion LZPO coating in promoting microstructural stability of the bulk NCM622 cathode. The introduction of NTE functional compounds might provide a universal strategy to address the stress accumulation and volume expansion issues of various cathode materials for advanced secondary-ion batteries.

7.
Mol Cancer ; 22(1): 55, 2023 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-36932387

RESUMO

BACKGROUND: Circular RNAs (circRNAs) can be encapsulated into exosomes to participate in intercellular communication, affecting the malignant progression of a variety of tumors. Dysfunction of CD8 + T cells is the main factor in immune escape from hepatocellular carcinoma (HCC). Nevertheless, the effect of exosome-derived circRNAs on CD8 + T-cell dysfunction needs further exploration. METHODS: The effect of circCCAR1 on the tumorigenesis and metastasis of HCC was assessed by in vitro and in vivo functional experiments. The function of circCCAR1 in CD8 + T-cell dysfunction was measured by enzyme-linked immunosorbent assay (ELISA), western blotting and flow cytometry. Chromatin immunoprecipitation, biotinylated RNA pull-down, RNA immunoprecipitation, and MS2 pull-down assays were used to the exploration of mechanism. A mouse model with reconstituted human immune system components (huNSG mice) was constructed to explore the role of exosomal circCCAR1 in the resistance to anti-PD1 therapy in HCC. RESULTS: Increased circCCAR1 levels existed in tumor tissues and exosomes in the plasma of HCC patients, in the culture supernatant and HCC cells. CircCCAR1 accelerated the growth and metastasis of HCC in vitro and in vivo. E1A binding protein p300 (EP300) and eukaryotic translation initiation factor 4A3 (EIF4A3) promoted the biogenesis of circCCAR1, and Wilms tumor 1-associated protein (WTAP)-mediated m6A modification enhanced circCCAR1 stability by binding insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3). CircCCAR1 acted as a sponge for miR-127-5p to upregulate its target WTAP and a feedback loop comprising circCCAR1/miR-127-5p/WTAP axis was formed. CircCCAR1 is secreted by HCC cells in a heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2B1)-dependent manner. Exosomal circCCAR1 was taken in by CD8 + T cells and caused dysfunction of CD8 + T cells by stabilizing the PD-1 protein. CircCCAR1 promoted resistance to anti-PD1 immunotherapy. Furthermore, increased cell division cycle and apoptosis regulator 1 (CCAR1) induced by EP300 promoted the binding of CCAR1 and ß-catenin protein, which further enhanced the transcription of PD-L1. CONCLUSIONS: The circCCAR1/miR-127-5p/WTAP feedback loop enhances the growth and metastasis of HCC. Exosomal circCCAR1 released by HCC cells contributes to immunosuppression by facilitating CD8 + T-cell dysfunction in HCC. CircCCAR1 induces resistance to anti-PD1 immunotherapy, providing a potential therapeutic strategy for HCC patients.


Assuntos
Proteínas Reguladoras de Apoptose , Carcinoma Hepatocelular , Proteínas de Ciclo Celular , Exossomos , Neoplasias Hepáticas , MicroRNAs , Animais , Humanos , Camundongos , Proteínas Reguladoras de Apoptose/genética , Carcinoma Hepatocelular/patologia , Linfócitos T CD8-Positivos , Proteínas de Ciclo Celular/genética , Linhagem Celular Tumoral , Proliferação de Células/genética , RNA Helicases DEAD-box/metabolismo , Fator de Iniciação 4A em Eucariotos/metabolismo , Exossomos/metabolismo , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/patologia , MicroRNAs/genética , MicroRNAs/metabolismo , RNA Circular/genética , RNA Circular/metabolismo
8.
Nat Commun ; 14(1): 256, 2023 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-36650201

RESUMO

The low fraction of non-radiative recombination established the foundation of metal halide perovskite solar cells. However, the origin of low non-radiative recombination in metal halide perovskite materials is still not well-understood. Herein, we find that the non-radiative recombination in twinning-tetragonal phase methylammonium lead halide (MAPbIxCl3-x) is apparently suppressed by applying an electric field, which leads to a remarkable increase of the open-circuit voltage from 1.12 V to 1.26 V. Possible effects of ionic migration and light soaking on the open-circuit voltage enhancement are excluded experimentally by control experiments. Microscopic and macroscopic characterizations reveal an excellent correlation between the ferroelastic lattice deformation and the suppression of non-radiative recombination. The calculation result suggests the existence of lattice polarization in self-stabilizable deformed domain walls, indicating the charge separation that facilitated by lattice polarization is accountable for the suppressed non-radiative recombination. This work provides an understanding of the excellent performance of metal halide perovskite solar cells.

9.
Angew Chem Int Ed Engl ; 62(12): e202218318, 2023 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-36578144

RESUMO

Designing polymeric photocatalysts at the molecular level to modulate the photogenerated charge behavior is a promising and challenging strategy for efficient hydrogen peroxide (H2 O2 ) photosynthesis. Here, we introduce electron-deficient 1,4-dihydroxyanthraquinone (DHAQ) into the framework of resorcinol-formaldehyde (RF) resin, which modulates the donor/acceptor ratio from the perspective of molecular design for promoting the charge separation. Interestingly, H2 O2 can be produced via oxygen reduction and water oxidation pathways, verified by isotopic labeling and in situ characterization techniques. Density functional theory (DFT) calculations elucidate that DHAQ can reduce the energy barrier for H2 O2 production. RF-DHAQ exhibits excellent overall photosynthesis of H2 O2 with a solar-to-chemical conversion (SCC) efficiency exceeding 1.2 %. This work opens a new avenue to design polymeric photocatalysts at the molecular level for high-efficiency artificial photosynthesis.

10.
Nanoscale ; 15(2): 588-598, 2023 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-36484351

RESUMO

With large specific capacity, wide voltage window, and high energy density, Li-rich layered oxides have been considered as a promising cathode candidate for advanced lithium-ion batteries (LIBs). However, their commercial application is challenging due to severe capacity degradation and voltage fading caused by irreversible oxygen evolution and phase transition upon repeated cycling. This work proposes an effective strategy to improve the long-term electrochemical performances of Li1.2Mn0.56Ni0.17Co0.07O2 (LMNCO) by constructing multifunctional nanolayers composed of element-doping, layered-spinel heterostructural connection, and fast ion conductor shell via a facile method. The Li0.09B0.97PO4 (LBPO) coating shell acts as a fast ion carrier and physical screen to promote Li+ diffusion and isolate side reactions at the cathode-electrolyte interface; moreover, two-phase transitional region provides three-dimensional channel to facilitate Li+ transport and inhibit phase transition. Besides, B3+ and PO43--doping collaborates with oxygen vacancies to stabilize lattice oxygen and restrain oxygen evolution from the bulk active cathode. The optimized LMNCO@LBPO material exhibits a superior capacity retention of 78.6%, higher than that of the pristine sample (49.3%), with the mitigated voltage fading of 0.73 mV per cycle after 500 cycles at 1 C. This study opens up an avenue for the surface modification to the electrochemical properties and perspective application of Li-rich cathodes in high-performance LIBs.

11.
Biomed Mater Eng ; 34(1): 1-11, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35180101

RESUMO

BACKGROUND: Acute liver failure is one of the most intractable clinical problems. The use of bioartificial livers may solve donor shortage problems. Human umbilical cord mesenchymal stem cells (hUCMSCs) are an excellent seed cell choice for artificial livers because they change their characteristics to resemble hepatocyte-like cells (HLCs) following artificial liver transplantation. OBJECTIVE: This study aimed to determine whether the immunological characteristics of hUCMSCs are changed after being transformed into hepatocyte-like cells. METHODS: HUCMSCs were isolated by the adherent method. The following hUCMSC surface markers were detected using flow cytometry: CD45, CD90, CD105, CD34, and octamer-binding transcription factor 4 (OCT-4). Functional detection of adipogenic differentiation was performed. The hUCMSCs were cultured in complete medium (control group) or induction medium (induction group), and flow cytometry was used to detect cell surface markers. Peritoneal lavage fluid was collected after intraperitoneal injection of 1 × 106 cells/mouse over 40 minutes. The leukocyte count, labeled CD45, CD3, CD4 and CD8 antibodies, and flow detection of T lymphocyte subsets were determined using the peritoneal lavage fluid. RESULTS: Using phenotypic and functional identification, hUCMSCs were successfully isolated using a two-step induction method. The surface markers of the hUCMSCs cells changed after HLC induction. In vivo immune results showed that hUCMSCs and HLsC induced leukocyte production. CONCLUSION: Hepatic induction of hUCMSCs changes their cell surface markers. Both HLCs and hUCMSCs cause leukocytosis in vivo, but the immune response induced by HLCs is slightly stronger.


Assuntos
Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais , Humanos , Animais , Camundongos , Diferenciação Celular , Fígado , Hepatócitos , Cordão Umbilical , Transplante de Células-Tronco Mesenquimais/métodos
12.
Nat Mater ; 21(12): 1396-1402, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36396958

RESUMO

Cations with suitable sizes to occupy an interstitial site of perovskite crystals have been widely used to inhibit ion migration and promote the performance and stability of perovskite optoelectronics. However, such interstitial doping inevitably leads to lattice microstrain that impairs the long-range ordering and stability of the crystals, causing a sacrificial trade-off. Here, we unravel the evident influence of the valence states of the interstitial cations on their efficacy to suppress the ion migration. Incorporation of a trivalent neodymium cation (Nd3+) effectively mitigates the ion migration in the perovskite lattice with a reduced dosage (0.08%) compared to a widely used monovalent cation dopant (Na+, 0.45%). The photovoltaic performances and operational stability of the prototypical perovskite solar cells are enhanced with a trace amount of Nd3+ doping while minimizing the sacrificial trade-off.

13.
Chem Sci ; 13(28): 8334-8340, 2022 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-35919708

RESUMO

Accurate characterization of the longitudinal (along the thickness direction) carrier transport property is of significant importance for evaluating the quality and performance of perovskite thin films. Herein, we report the development of a modified transient reflection (TR) spectroscopy method to realize the direct observation and determination of the longitudinal carrier transport process in MAPbI3 polycrystalline thin films. Unlike the traditional TR spectroscopy, the carrier transport dynamics along the film thickness is resolved by making the pump (excitation) and probe beams spatially separated on each side of the film, so that the carrier transport from the excitation side to the probe side is directly captured. Utilizing this method, the longitudinal carrier diffusion coefficients (D) in various perovskite films with different thicknesses and grain sizes (extracted from SEM images) are determined, showing D values of ∼1.5 to 1.8 cm2 s-1 (∼0.5 to 0.8 cm2 s-1) for films with grain size larger (smaller) than the thickness. This empirical correlation between the longitudinal D and film thickness/grain size provides a reference for quick quality screening and evaluation of perovskite polycrystalline thin films.

14.
Transl Cancer Res ; 11(5): 1173-1187, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35706810

RESUMO

Background: Exosomes are becoming an important mediator of the interaction between tumor cells and the microenvironment. Ferroptosis is a newly discovered type of cell death. However, its role in the progression of liver cancer is largely unknown. The aim of the presents study was to analyze the mechanism by which hepatitis B virus (HBV)-positive liver cancer secretes exosomes to mediate the iron death of M1 macrophages, thereby promoting the development of liver cancer. Methods: Liver cancer tissues and peripheral blood with positive and negative clinical HBV infection were collected, and M-type macrophages, miR-142-3p, and recombinant solute carrier family 3, member 2 (SLC3A2) expressions were detected in the samples. CD80+ M1 macrophages and CD163+ M2 macrophages were isolated from the 2 tissues, and levels of miR-142-3p, SLC3A2, and ferroptosis markers were detected. Exosomes of HBV-positive hepatocellular carcinoma (HCC) cells were isolated and co-cultured with M1 macrophages to observe their effect on the invasion ability of HCC cells. Results: The expression of miR-142-3p significantly increased in the exosomes extracted from the peripheral blood of patients with HBV-positive liver cancer. Genes related to intracellular iron metabolism and homeostasis, such as ferritin heavy chain 1 (FTH1), transferrin receptor 1 (TfR1), recombinant glutathione peroxidase 4 (GPX4), and activating transcription factor 4 (ATF4), had abnormal expression levels in M1 macrophages. HBV-positive HCC exosomes treated with M1-type macrophages had a weakened inhibitory effect on the invasion of HCC cells, but ferroptosis inhibitors could reverse the effect of HBV-positive HCC exosomes treated M1-type macrophages on HCC cells. Knockdown of the expression of miR-142-3p can also weaken the invasive ability of liver cancer cells. Conclusions: The results of the present study confirmed that HBV-positive liver cancer cell exosomal miR-142-3p can promote the progression of liver cancer by inducing iron death of M1-type macrophages.

15.
J Gastrointest Oncol ; 13(2): 754-767, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35557596

RESUMO

Background: Most patients with hepatitis B virus (HBV) infection will develop hepatocellular carcinoma (HCC). This study aimed to explore the potential mechanism of miR-142-3p in HCC caused by HBV infection. Methods: HepG2 cells and M1 macrophages were cocultured and then infected with HBV to establish an in vitro model. MicroRNA (miRNA) and messenger RNA (mRNA) expression was analyzed by quantitative reverse transcription polymerase chain reaction (RT-qPCR) and Western blot. The protein expressions of COX2, ACSL4, PTGS2, GPX4, and NOX1 were analyzed by Western blot. Flow cytometry and TUNEL assays were used to assess cell reactive oxygen species (ROS) and ferroptosis, respectively. Cell invasion and migration were measured by Transwell assay. To evaluate the ferroptosis of M1-type macrophages, glutathione (GSH), malondialdehyde (MDA), and Fe2+ content was detected by corresponding kits. Dual luciferase reporter gene detection verified the targeting relationship between miR-142-3p and SLC3A2. Results: MiR-142-3p was highly expressed in HBV-infected HCC patients and HBV-infected M1-type macrophages. Inhibition of miR-142-3p or overexpression of SLC3A2 reversed ferroptosis and inhibited the proliferation, migration, and invasion of HCC cells. Conclusions: Our findings indicated that miR-142-3p promoted HBV-infected M1-type macrophage ferroptosis through SLC3A2, affecting the production of GSH, MDA, and Fe2+ and accelerating the development of HCC. The regulation of miR-142-3p and its target genes will help to clarify the pathogenesis of HCC induced by HBV infection and provide new theoretical foundations and therapeutic targets.

16.
Adv Sci (Weinh) ; 8(14): e2100786, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34021734

RESUMO

Low-dimensional hybrid metal halides are emerging as a highly promising class of single-component white-emitting materials for their unique broadband emission from self-trapped excitons (STEs). Despite substantial progress in the development of these metal halides, many challenges remain to be addressed to obtain a better fundamental understanding of the structure-property relationship and realize the full potentials of this class of materials. Here, via pressure regulation, a near 100% photoluminescence quantum yield (PLQY) of broadband emission is achieved in a corrugated 1D hybrid metal halide C5 N2 H16 Pb2 Br6 , which possesses a highly distorted structure with an initial PLQY of 10%. Compression reduces the overlap between STE states and ground state, leading to a suppressed phonon-assisted non-radiative decay. The PL evolution is systematically demonstrated to be controlled by the pressure-regulated exciton-phonon coupling which can be quantified using Huang-Rhys factor S. Detailed studies of the S-PLQY relation for a series of 1D hybrid metal halides (C5 N2 H16 Pb2 Br6 , C4 N2 H14 PbBr4 , C6 N2 H16 PbBr4 , and (C6 N2 H16 )3 Pb2 Br10 ) reveal a quantitative structure-property relationship that regulating S factor toward 28 leads to the maximum emission.

17.
RSC Adv ; 11(5): 2866-2871, 2021 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-35424236

RESUMO

All-inorganic perovskite materials have emerged as highly promising materials for solar cells and photoelectronic applications. However, the poor stability of perovskites in ambient conditions significantly hampers their practical applications. In this work, we report a three-step synthesis of size tunable CsPbX3 (X = Br, Cl, or I) quantum dots (QDs) embedded in zeolite-Y (CsPbX3-Y), which involves efficient chemical transformation of non-luminescent Cs4PbX6 to highly luminescent CsPbX3 by stripping CsX through an interfacial reaction with water. We show that the size and the emission of CsPbX3 in CsPbX3-Y can be tuned by the amount of water added as well as the halide composition. More importantly, the as-prepared CsPbX3-Y show significantly enhanced stability against moisture upon protection by zeolite-Y. This work not only reports a new pathway for the preparation of highly luminescent CsPbX3 but also provided new insights into the chemical transformation behavior and stabilization mechanism of these emerging perovskites.

18.
J Phys Chem Lett ; 11(17): 6956-6963, 2020 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-32787195

RESUMO

Understanding the photoinduced carrier dynamics in Cs2AgBiBr6 double perovskites is essential for their application in optoelectronic devices. Herein, we report an investigation on the temperature-dependent carrier dynamics in a Cs2AgBiBr6 single crystal (SC). The time-resolved photoluminescence (TRPL) measurement indicates that the majority of carriers (>99%) decay through a fast trapping process at room temperature, and as the temperature decreases to 123 K, the population of carriers with a slow fundamental decay kinetics rises to ∼50%. We show that the carrier diffusion coefficient (theoretical diffusion length) varies from 0.020 ± 0.003 cm2 s-1 (0.70 µm) at 298 K to 0.11 ± 0.010 cm2 s-1 (2.44 µm) at 123 K. However, in spite of the long diffusion length, the population of carriers that can perform long-distance transport is restricted by the trap state, which is likely a key reason limiting the performance of Cs2AgBiBr6 optoelectronic devices.

19.
Commun Biol ; 3(1): 228, 2020 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-32385384

RESUMO

The toxic kernel cake of Jatropha curcas (KCakeJ) is an emerging health and environmental concern. Although phorbol esters are widely recognized as the major toxin of KCakeJ, convincing evidence is absent. Here, we show that rather than phorbol esters an isomeric mixture of 11-hydroxy-9E-octadecenoic acid, 12-hydroxy-10E-octadecenoic acid and 12-hydroxy-10Z-octadecenoic acid (hydroxy-octadecenoic acids, molecular formula C18H34O3) is the major toxic component. The toxicities of hydroxy-octadecenoic acids on experimental animals, e.g. acute lethality, causing inflammation, pulmonary hemorrhage and thrombi, allergies, diarrhea and abortion, are consistent with those on human/animals caused by Jatropha seed and/or KCakeJ. The hydroxyl group and the double bond are essential for hydroxy-octadecenoic acids' toxicity. The main pathway of the toxicity mechanism includes down-regulating UCP3 gene expression, promoting ROS production, thus activating CD62P expression (platelet activation) and mast cell degranulation. The identification of the major toxin of KCakeJ lays a foundation for establishing an environmentally friendly Jatropha biofuel industry.


Assuntos
Jatropha/toxicidade , Ácidos Oleicos/química , Ésteres de Forbol/química , Sementes/química , Animais , Carpas , Carpa Dourada , Cobaias , Humanos , Jatropha/química , Células MCF-7 , Camundongos , Ratos , Ratos Sprague-Dawley , Sementes/toxicidade
20.
ACS Appl Mater Interfaces ; 12(1): 698-705, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31815408

RESUMO

Defects locating within grain boundaries or on the film surface, especially organic cation vacancies and iodine vacancies, make the fabrication of perovskite solar cells (PSCs) with superior performance a challenge. Organic ammonium iodide is a promising candidate and has been frequently used to passivate these defects by forming two-dimensional (2D) perovskite. In this work, it is found that the chain length of organic ammonium iodide is a crucial factor on the defect passivation effect. Compared to butylammonium iodide, the hexylammonium iodide (HAI)-derived 2D perovskite is more efficient in decreasing interfacial defects, resulting in a notably enhanced photoluminescence lifetime and a more suppressed interfacial charge recombination process. As a consequence, the ultimate power conversion efficiency (PCE) has reached 20.62% (3D + HAI) as compared to 18.83% (3D). Moreover, the long-term durability of the corresponding PSCs against humidity and heat is simultaneously improved. This work once again demonstrates that the 2D/3D structure is promising for further improving the PCE and stability of PSCs.

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