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1.
Lab Chip ; 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39289895

RESUMO

We propose an innovative design for interdigital transducers (IDTs), enabling phase modulation of surface acoustic waves (SAWs) with a dislocated electrode structure. By designing the size and arrangement of these dislocated IDTs, a novel type of Airy SAWs can be generated, exhibiting self-accelerating, self-bending, and self-healing characteristics. The acceleration of the generated Airy SAW is 0.081 cm-1. Furthermore, particles and bubbles can be precisely manipulated using the generated Airy SAW. The proposed dislocated IDTs could be used for generation of many other types of SAWs, hence holding great promise for applications including SAW shaping, particle manipulation/sorting, and acoustic sensing/detection.

2.
Luminescence ; 39(9): e4886, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39285587

RESUMO

A novel seminaphthorhodafluor-based fluorescent probe was designed and prepared. It exhibited an outstanding off-on fluorescence response (about 45-fold enhancement) to Cu2+ because the structure changed from a spirocyclic form to a ring-open state. It showed satisfactory detection performances for Cu2+ with fast response speed, high selectivity and anti-interference, and a low detection limit (22.9 nM) due to its long emission wavelength and off-on fluorescence response mode. This probe was also satisfactorily applied for the monitoring of Cu2+ in living cells and zebrafish.


Assuntos
Cobre , Corantes Fluorescentes , Peixe-Zebra , Animais , Corantes Fluorescentes/química , Corantes Fluorescentes/síntese química , Cobre/análise , Cobre/química , Humanos , Espectrometria de Fluorescência , Estrutura Molecular , Células HeLa , Rodaminas/química , Imagem Óptica
3.
Nat Commun ; 15(1): 8346, 2024 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-39333142

RESUMO

Strain engineering plays an important role in tuning electronic structure and improving catalytic capability of biocatalyst, but it is still challenging to modify the atomic-scale strain for specific enzyme-like reactions. Here, we systematically design Pt single atom (Pt1), several Pt atoms (Ptn) and atomically-resolved Pt clusters (Ptc) on PdAu biocatalysts to investigate the correlation between atomic strain and enzyme-like catalytic activity by experimental technology and in-depth Density Functional Theory calculations. It is found that Ptc on PdAu (Ptc-PA) with reasonable atomic strain upshifts the d-band center and exposes high potential surface, indicating the sufficient active sites to achieve superior biocatalytic performances. Besides, the Pd shell and Au core serve as storage layers providing abundant energetic charge carriers. The Ptc-PA exhibits a prominent peroxidase (POD)-like activity with the catalytic efficiency (Kcat/Km) of 1.50 × 109 mM-1 min-1, about four orders of magnitude higher than natural horseradish peroxidase (HRP), while catalase (CAT)-like and superoxide dismutase (SOD)-like activities of Ptc-PA are also comparable to those of natural enzymes. Biological experiments demonstrate that the detection limit of the Ptc-PA-based catalytic detection system exceeds that of visual inspection by 132-fold in clinical cancer diagnosis. Besides, Ptc-PA can reduce multi-organ acute inflammatory damage and mitigate oxidative stress disorder.


Assuntos
Biocatálise , Catalase , Ouro , Platina , Platina/química , Ouro/química , Humanos , Catalase/química , Catalase/metabolismo , Paládio/química , Peroxidase do Rábano Silvestre/química , Peroxidase do Rábano Silvestre/metabolismo , Superóxido Dismutase/química , Superóxido Dismutase/metabolismo , Catálise , Teoria da Densidade Funcional , Nanopartículas Metálicas/química
4.
Ecotoxicol Environ Saf ; 284: 116974, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-39232298

RESUMO

Biochar has been recognised as an efficacious amendment for the remediation of compound heavy metal contamination in soil. However, the molecular mechanism of biochar-mediated tolerance to compound heavy metal toxicity in cotton is unknown. The objective of this research was to investigate the positive impact of biochar (10 g·kg-1) on reducing damage caused by compound heavy metals (Cd, Pb, and As) in cotton (Gossypium hirsutum L.). The results revealed that biochar reduced Cd concentrations by 24.9 % (roots), and decreased Pb concentrations by 37.1 % (roots) and 59.53 % (stems). Biochar maintained ionic homoeostasis by regulating the expression of metal transporter proteins such as ABC, HIPP, NRAMP3, PCR, and ZIP, and genes related to the carbon skeleton and plasma membrane. Biochar also downregulated genes related to photosynthesis, thereby increasing photosynthesis. Biochar re-established redox homoeostasis in cotton by activating signal transduction, which regulated the activity of the enzymes POD, SOD, and CAT activity; and the expression of related genes. This research revealed the molecular mechanism by which biochar confers resistance to the harmful effects of compound heavy metal toxicity in cotton. The application of biochar as a soil amendment to neutralise the toxicity of compound heavy metals is recommended for cash crop production.


Assuntos
Carvão Vegetal , Gossypium , Metais Pesados , Poluentes do Solo , Gossypium/genética , Gossypium/efeitos dos fármacos , Poluentes do Solo/toxicidade , Metais Pesados/toxicidade , Cádmio/toxicidade , Chumbo/toxicidade , RNA-Seq , Fotossíntese/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos
6.
Sex Med ; 12(2): qfae029, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38817951

RESUMO

Objective: Although many clinical studies have shown that ROUX-en-Y gastric bypass (RYGB) surgery significantly improves metabolic syndrome-related erectile dysfunction (MED), the role and mechanism are unclear. Aim: In this study we used a mouse model to explore how RYGB improves MED induced by a high-fat diet (HFD). Methods: We established a mouse model of metabolic syndrome by feeding an HFD for 16 weeks. The mice were randomly assigned to the standard chow diet (SCD), HFD, or RYGB groups. Body weight, fasting blood glucose, plasma insulin, and total plasma cholesterol were analyzed. Erectile responses were evaluated by determining the mean systolic blood pressure and the intracavernosal pressure (ICP). Penile histologic examination (Masson's trichrome and immunohistochemical stain) and Western blot were performed. Result: Compared with the SCD group, the ICP in the sham group was significantly lower, and the ICP of the RYGB was significantly increased. Masson's trichrome and immunohistochemical staining showed that the content of endothelium and smooth muscle in the corpus cavernosum of mice with MED was significantly reduced. Western blot analysis showed a significant decrease in α-smooth muscle actin and a significant increase in osteopontin in penile tissue in the sham group, which was improved by RYGB surgery. Furthermore, RYGB significantly increased IRS-1/PI3K/Akt/eNOS phosphorylation. Clinical Translation: In this study we explored the mechanism of bariatric surgery to improve erectile dysfunction associated with metabolic syndrome and provided a theoretical basis for clinical research. Strengths and Limitations: First, we did not investigate the mechanism by which RYGB affects the IRS-1/PI3K/Akt/eNOS signaling pathway. Second, the effect of the IRS-1/PI3K/Akt/eNOS signaling pathway on the function of corpus cavernosum endothelial cells and smooth muscle cells remains to be investigated in cellular studies. Conclusion: This study demonstrated that RYGB may not only improve metabolic parameters but also restore erectile function in MED patients. The mechanism of the therapeutic effect of RYGB may be reactivation of the IRS-1/PI3K/Akt/eNOS pathway.

7.
Pharmaceuticals (Basel) ; 16(12)2023 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-38139799

RESUMO

Microwave ablation (MWA) is an effective treatment for liver cancer (LC), but its impact on distant tumors remains to be fully elucidated. This study investigated the abscopal effects triggered by MWA treatment of LC, at different power levels and with or without combined immune checkpoint inhibition (ICI). We established a mouse model with bilateral subcutaneous LC and applied MWA of varied power levels to ablate the right-sided tumor, with or without immunotherapy. Left-sided tumor growth was monitored to assess the abscopal effect. Immune cell infiltration and distant tumor neovascularization were quantified via immunohistochemistry, revealing insights into the tumor microenvironment and neovascularization status. Th1- and Th2-type cytokine concentrations in peripheral blood were measured using ELISA to evaluate systemic immunological changes. It was found that MWA alone, especially at lower power, promoted distant tumor growth. On the contrary, combining high-power MWA with anti-programmed death (PD)-1 therapy promoted CD8+ T-cell infiltration, reduced regulatory T-cell infiltration, upregulated a Th1-type cytokine (TNF-α) in peripheral blood, and inhibited distant tumor growth. In summary, combining high-power MWA with ICI significantly enhances systemic antitumor immune responses and activates the abscopal effect, offering a facile and robust strategy for improving treatment outcomes.

8.
Phys Rev Lett ; 131(13): 136901, 2023 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-37831991

RESUMO

Manipulating bosonic condensates with electric fields is very challenging as the electric fields do not directly interact with the neutral particles of the condensate. Here we demonstrate a simple electric method to tune the vorticity of exciton-polariton condensates in a strong coupling liquid crystal (LC) microcavity with CsPbBr_{3} microplates as active material at room temperature. In such a microcavity, the LC molecular director can be electrically modulated giving control over the polariton condensation in different modes. For isotropic nonresonant optical pumping we demonstrate the spontaneous formation of vortices with topological charges of +1, +2, -2, and -1. The topological vortex charge is controlled by a voltage in the range of 1 to 10 V applied to the microcavity sample. This control is achieved by the interplay of a built-in potential gradient, the anisotropy of the optically active perovskite microplates, and the electrically controllable LC molecular director in our system with intentionally broken rotational symmetry. Besides the fundamental interest in the achieved electric polariton vortex control at room temperature, our work paves the way to micron-sized emitters with electric control over the emitted light's phase profile and quantized orbital angular momentum for information processing and integration into photonic circuits.

9.
Opt Express ; 31(19): 30578-30587, 2023 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-37710598

RESUMO

This paper presents a novel tunable narrowband photodetector based on Ag-MgF2-Ag (metal-dielectric-metal: MDM) Fabry-Perot (FP) microcavity structure. The tunability is achieved through precise adjustment of the thickness of the metal and intermediate dielectric layers of the FP microcavity, taking into account the response spectral range of planar perovskite. After optimizing the parameters mentioned above, the prototype devices were prepared by combining the perovskite layer and MDM layer. The center wavelength of the planar detector can be tuned from 430 nm to 680 nm within the detection band of 400-800 nm, with a narrow FWHM about 30 nm and a relatively high response of 0.05 A/W @ 5 V bias voltage for 500 nm. Meanwhile the rise and fall times of the detector are 375 ms and 550 ms, respectively. The experimental results are corroborated by the theory. Our design is highly beneficial to such applications as hyperspectral photography and color-related active optical devices, which paves the way to design this kind of triple structure.

10.
Sci Adv ; 9(31): eadh7828, 2023 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-37531420

RESUMO

Strong fluorescence and high catalytic activities cannot be achieved simultaneously due to conflicts in free electron utilization, resulting in a lack of bioactivity of most near-infrared-II (NIR-II) fluorophores. To circumvent this challenge, we developed atomically precise Au22 clusters with strong NIR-II fluorescence ranging from 950 to 1300 nm exhibiting potent enzyme-mimetic activities through atomic engineering to create active Cu single-atom sites. The developed Au21Cu1 clusters show 18-fold higher antioxidant, 90-fold higher catalase-like, and 3-fold higher superoxide dismutase-like activities than Au22 clusters, with negligible fluorescence loss. Doping with single Cu atoms decreases the bandgap from 1.33 to 1.28 eV by predominant contributions from Cu d states, and Cu with lost electron states effectuates high catalytic activities. The renal clearable clusters can monitor cisplatin-induced renal injury in the 20- to 120-minute window and visualize it in three dimensions using NIR-II light-sheet microscopy. Furthermore, the clusters inhibit oxidative stress and inflammation in the cisplatin-treated mouse model, particularly in the kidneys and brain.


Assuntos
Ouro , Imageamento Tridimensional , Animais , Camundongos , Cisplatino , Corantes Fluorescentes , Microscopia de Fluorescência , Imagem Óptica/métodos
11.
Opt Express ; 31(11): 18063-18071, 2023 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-37381524

RESUMO

X-rays have developed into an essential tool in variety of fields, such as biology, materials, chemistry, and physics etc. Numerous X-ray types, including the orbital angular momentum (OAM), the Laguerre-Gauss, and the Hermite-Gauss states, have been proposed. This greatly enhances the depth of application of X-ray. The X-ray states described above are mostly produced by binary amplitude diffraction elements. In light of this, this paper proposes a flat X-ray diffraction grating based on caustic theory to generate Airy-type X-ray. It is proved by the simulation of multislice method that the proposed grating can generate the Airy beam in the X-ray field. The results show that the generated beams have a secondary parabolic trajectory deflection with the propagation distance, which is consistent with the theory. Inspired by the success of Airy beam in light-sheet microscope, the Airy-type X-ray can be anticipated to enable novel image capability for bio or nanoscience.

12.
Nitric Oxide ; 134-135: 72-78, 2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-37062466

RESUMO

OBJECTIVES: The aim of this study was to synthesize and characterize a novel NO donor, PEI-PO-NONOate, using propylene oxide and to investigate its biosafety and therapeutic efficacy via nasal administration in vitro and vivo. EXPERIMENTAL PROCEDURES: The PEI-PO-NONOate was synthesized based on polyethylenimine (PEI) with different molecular weights and characterized using Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and ultraviolet (UV) spectroscopy. Cytotoxicity assays were performed on mouse fibroblast cells L929 and human nasal mucosa epithelial cells (HNEpC), and a rat middle cerebral artery occlusion (MCAO) model was established to evaluate the therapeutic efficacy of PEI-PO-NONOate via nasal administration. RESULTS: The PEI-PO-NONOate was found to be stable under dark, dry, and airproof conditions, and its release was accelerated in an aqueous phase or acidic environment, while it was slowed down in a polyethylene glycol (PEG) mixture system. The NO donor released approximately 0.4, 0.5, and 0.6 µmol of gaseous NO from 1.0 mg of the polymer based on PEI600, PEI1800, and PEI10K, respectively. Cytotoxicity assays showed that the PEI-PO-NONOates had a cryoprotective effect as compared with PEI and PEI-PO. Furthermore, nasal administration of PEI-PO-NONOates resulted in a significant reduction in overall necrotic ratio as compared with the control group (16.4% versus 24.6%, p < 0.05). CONCLUSION: The findings of this study suggest that PEI-PO-NONOates may have potential as an adjuvant therapy for acute ischemic stroke when administered via the nasal route.


Assuntos
AVC Isquêmico , Doadores de Óxido Nítrico , Camundongos , Ratos , Humanos , Animais , Doadores de Óxido Nítrico/farmacologia , Doadores de Óxido Nítrico/uso terapêutico , Administração Intranasal , Polietilenoglicóis
13.
Curr Cancer Drug Targets ; 23(7): 564-571, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36790005

RESUMO

OBJECTIVE: Evaluate the efficacy and safety of transarterial chemoembolization (TACE) sequential with hepatic arterial infusion chemotherapy (HAIC) and a tyrosine kinase inhibitor (TKI) for unresectable large hepatocellular carcinoma (HCC). METHODS: Patients with HCC size > 70 mm were included. They received 1-3 cycles of TACE and sequential HAIC every 3-6 weeks for 2-6 cycles, with each cycle given over a period of 48 hours (oxaliplatin plus fluorouracil/leucovorin). Patients also received sorafenib or lenvatinib beginning at the first TACE cycle and continuing until disease progression. Objective response rate (ORR) at 3 months was the primary endpoint. Progression-free survival (PFS) and safety were the secondary endpoints. RESULTS: From January 2020 to December 2020, 41 patients were included, who were divided into the drug-eluting bead TACE (DEB-TACE) group (n=13) and conventional TACE (cTACE) group (n=28). The overall ORR was 56.1% (23/41) using mRECIST criteria and 34.1% (14/41) using RECIST1.1 criteria. The median PFS of the cohort was 8 months. The ORR of the DEB-TACE group was 76.9% (10/13) vs. 46.4% (13/28) for the cTACE group (p = 0.06). The median PFS of the DEBTACE group was 12 months, and 6 months in the cTACE group (p = 0.09). Conversion hepatectomy was performed in 2 patients in the DEB-TACE group (15.4%), and in 3 patients in the cTACE group (10.7%). ALT/AST elevated, hypertension, nausea, and vomiting were the common treatment related adverse events. There was no treatment related death. CONCLUSION: TACE sequential with HAIC combined a TKI is a well-tolerated and promising tripletherapy for large, unresectable HCC.


Assuntos
Carcinoma Hepatocelular , Quimioembolização Terapêutica , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , Resultado do Tratamento , Inibidores de Proteínas Quinases/uso terapêutico
14.
J Vasc Access ; : 11297298231151459, 2023 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-36708010

RESUMO

OBJECTIVE: Our objective was to evaluate the feasibility of XperCT combined fluoroscopy to guide sharp recanalization for the treatment of chronic thoracic venous occlusive disease in hemodialysis patients. METHODS: The records of hemodialysis patients with chronic thoracic venous occlusive disease who received endovascular sharp recanalization after conventional techniques failed were retrospectively reviewed. The sharp devices used for recanalization included the stiff end of a guidewire, Chiba biopsy needle, RUPS-100 set, and transseptal needle. The needle was advanced toward a target placed at the opposite end of the occlusion and was guided by fluoroscopy and/or XperCT. While the guidewire crossed the occlusion, endovascular procedures such as percutaneous angioplasty were performed for the treatment of the occlusion. RESULTS: The analysis included 32 sharp thoracic vein recanalization procedures in 29 patients. Two attempts in one patient failed, and in one patient the first attempt failed but the second attempt was successful. In one patient, two separate successful procedures were performed, and the other 26 procedures in 26 patients were successful. The overall technical success rate of sharp recanalization was 90%. The mean number of puncture attempts in the combined group was less than that of the fluoroscopy-guided alone group (2 vs 5, p < 0.05). The success rate of sharp recanalization in the combined group was higher (100% vs 86%), and the recanalization time (28.5 min vs 36 min, p > 0.05) was no different. There was no statistical difference in procedure-related complications between the groups. CONCLUSION: XperCT can facilitate sharp recanalization for the treatment of chronic thoracic venous occlusive disease in hemodialysis patients.

15.
Anal Bioanal Chem ; 415(18): 4245-4254, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36102972

RESUMO

Chiral recognition is an emerging field of modern chemical analysis, and the development of health-related fields depends on the production of enantiomers. Cellulose is a kind of natural polymer material with certain chiral recognition ability. Limited by the chiral recognition ability of natural cellulose itself, more cellulose derivatives have been gradually developed for chiral recognition and separation. Based on the difference in action between cellulose derivatives and enantiomers, this work synthesized cellulose-tris(4-methylphenylcarbamate) (CMPC) chiral recognition mediators and a CMPC-functionalized extended-gate organic field effect transistor (EG-OFET) was constructed for the first time. Three chiral molecules were selected as model analytes to evaluate the enantiomeric recognition ability of the platform, including threonine (Thr), 2-chloromandelic acid (CA), and 1,2-diphenylethylenediamine (DPEA). The detection limit for 1,2-diphenylethylenediamine (DPEA) is down to 10-13 M. Through the amplification effect of the EG-OFET platform, the difference in the interaction between CMPC and three chiral molecules with different structures is converted into a current signal output. At the same time, the enantiomer discrimination mechanism of CMPC was further studied by means of spectroscopy and nuclear magnetic resonance.


Assuntos
Celulose , Etilenodiaminas , Celulose/química , Polímeros , Estereoisomerismo
16.
Small Methods ; 7(5): e2201086, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36446639

RESUMO

Although immunotherapy of hepatocellular carcinoma using immune checkpoint inhibitors has achieved certain success, only a subset of patients benefits from this therapeutic strategy. The combination of immunostimulatory chemotherapeutics represents a promising strategy to enhance the effectiveness of immunotherapy. However, it is hampered by the poor delivery of conventional chemotherapeutics. Here, it is shown that H-ferritin nanocages loaded with doxorubicin (DOX@HFn) show potent chemo-immunotherapy in hepatocellular carcinoma tumor models. DOX@HFn is constructed with uniform size, high stability, favorable drug loading, and intracellular acidity-driven drug release. The receptor-mediated targeting of DOX@HFn to liver cancer cells promote cellular uptake and tumor penetration in vitro and in vivo. DOX@HFn triggers immunogenic cell death to tumor cells and promotes the subsequent activation and maturation of dendritic cells. In vivo studies in H22 subcutaneous hepatoma demonstrate that DOX@HFn significantly inhibits the tumor growth with >30% tumors completely eliminated, while alleviating the systemic toxicity of free DOX. DOX@HFn also exhibits robust antitumor immune response and tumoricidal effect in a more aggressive Hepa1-6 orthotopic liver tumor model, which is confirmed by the in situ magnetic resonance imaging and transcriptome sequencing. This study provides a facile and robust strategy to improve therapeutic efficacy of liver cancer.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológico , Ferritinas/uso terapêutico , Morte Celular Imunogênica , Doxorrubicina/farmacologia , Doxorrubicina/uso terapêutico , Imunoterapia
17.
Nanoscale ; 14(46): 17096-17118, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36382501

RESUMO

Natural hyperbolic materials (HMs) in two dimensions (2D) have an extraordinarily high anisotropy and a hyperbolic dispersion relation. Some of them can even sustain hyperbolic polaritons with great directional propagation and light compression to deeply sub-wavelength scales due to their inherent anisotropy. Herein, the anisotropic optical features of 2D natural HMs are reviewed. Four hyperbolic polaritons (i.e., phonon polaritons, plasmon polaritons, exciton polaritons, and shear polaritons) as well as their generation mechanism are discussed in detail. The natural merits of 2D HMs hold promise for practical quantum photonic applications such as valley quantum interference, mid-infrared polarizers, spontaneous emission enhancement, near-field thermal radiation, and a new generation of optoelectronic components, among others. The conclusion of these analyses outlines existing issues and potential interesting directions for 2D natural HMs. These findings could spur more interest in anisotropic 2D atomic crystals in the future, as well as the quick generation of natural HMs for new applications.

18.
Appl Opt ; 61(13): 3550-3557, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-36256392

RESUMO

Both the lighting quality and driving safety inside the tunnel have been quite a concern around the world. In this study, a plate with prism array of total internal reflection (TIR-PA) has been designed to enhance the lighting on the road surface inside the tunnel in adherence to traffic safety as well as energy savings. Such optical elements, above the tunnel sidewall, can redirect the rays emitted from both the headlight and lighting devices to the road surface, which supports higher flux on the road. Simultaneously, the simulation is conducted with consideration of practical factors based on the mathematical model and edge-ray principle to attain the effect of the TIR-PA plates. On the one hand, for the rays from the lighting devices, the enhancement rate of illuminance has reached 12.60%-16.58%, which is attributed to TIR-PA plates above the different sidewalls of the Lambertian scattering property. TIR-PA can be suitable for various sidewall materials due to the small effect of illumination reduction. On the other hand, 30.2%-32.2% rays of the headlight source received by the sidewall, due to the effect of TIR-PA plates, are redirected to the driving distance for 27.3-71.9 m, which makes 15.9-31.1m2 of road surface brighter. It makes contributions to the improvement of illuminance distribution and drivers' pre-judgment. In the future, broader applications regarding the TIR-PA plates will be explored widely in tunnel lighting systems due to the low production cost.

19.
Small ; 18(47): e2204271, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36228104

RESUMO

The surface properties of organic-inorganic hybrid perovskites can strongly affect the efficiency and stability of corresponding devices. Even though different surface passivation methods are developed, the microscopic structures of solution-processed perovskite film surfaces are not systematically studied. This study uses low-temperature scanning tunneling microscopy to study the organic-inorganic hybrid perovskite thin films, MA0.4 FA0.6 PbI3 and MAPbI3 , synthesized by the spin-coating method. Flat surface structures, atomic steps, and crystal grain boundaries are resolved at an atomic resolution. The surface imperfections are also characterized, as well as the dominant defects. Simulations on different types of iodine vacancy configurations are performed by density functional theory calculations. In addition, it is observed that the surface iodine lattice structure is unstable during scanning. Tip scanning can also cause the vertical migration of surface iodine ions. The measurements provide the direct visualizations of the surface imperfections of the solution-processed perovskite films. They are essential for understanding the surface-related optoelectronic effects and rationally designing more efficient surface passivation methods.

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