Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 70
Filtrar
1.
Adv Mater ; : e2400493, 2024 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-38733358

RESUMO

Full-Stokes polarization detection, with high integration and portability, offers an efficient path toward next-gen multi-information optoelectronic systems. Nevertheless, current techniques relying on optical filters create rigid and bulky configurations, limiting practicality. Here, we first report a flexible, filter-less full-Stokes polarimeter featuring a uniaxial-oriented chiral perovskite film. We find that, the strategic manipulation of the surfactant-mediated Marangoni effect during blade coating, is crucial for guiding an equilibrious mass transport to achieve oriented crystallization. Through this approach, the obtained uniaxial-oriented chiral perovskite films inherently possess anisotropy and chirality, and thereby with desired sensitivity to both Linearly Polarized Light (LPL) and Circularly Polarized Light (CPL) vectors. The uniaxial-oriented crystalline structure also improves photodetection, achieving a specific detectivity of 5.23 × 1013 Jones, surpassing non-oriented devices by 10x. The as-fabricated flexible polarimeters enable accurate capture of full-Stokes polarization without optical filters, exhibiting slight detection errors for the Stokes parameters: ΔS1 = 9.2%, ΔS2 = 8.6%, and ΔS3 = 6.5%, approaching the detection accuracy of optics-filter polarimeters. Our proof of concept also demonstrates applications in matrix polarization imaging. This article is protected by copyright. All rights reserved.

3.
Front Plant Sci ; 15: 1304913, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38516664

RESUMO

Okra has been widely cultivated worldwide. Consumers appreciate its nutritional value and delicious taste. However, okra is very perishable after harvest because of rapid senescence and high susceptibility to mechanical injuries, which limits its storage life and reduces consumer acceptance. This study examined the influence of melatonin treatment on senescence process and endogenous plant signalling molecules in postharvest okras. The results indicated that melatonin treatment delayed senescence by increasing the endogenous melatonin content through upregulation of its biosynthetic genes. In addition, the treatment increased the contents of indole-3-acetic acid (IAA) and gibberellin (GA) due to the positive modulation of their metabolic and signalling genes. Furthermore, treated okras exhibited higher levels of γ-aminobutyric acid (GABA) but lower abscisic acid (ABA) content, contributing to the delayed senescence process compared to control. Overall, the findings suggested that melatonin postponed senescence in okras fruit by positively regulating endogenous signalling molecules such as melatonin, IAA, GABA, GA, and ABA.

4.
Macromol Rapid Commun ; 45(9): e2300689, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38288905

RESUMO

Polyionic liquid hydrogels attract increasing attention due to their unique properties and potential applications. However, research on amino acid-based polyionic liquid hydrogels is still in its infancy stage. Moreover, the effect of amino acid types on the properties of hydrogels is rarely studied to date. In this work, amino acid-based polyionic liquid hydrogels (D/L-PCAA hydrogels) are synthesized by copolymerizing vinyl choline-amino acid ionic liquids and acrylic acids using Al3+ as a crosslinking agent and bacterial cellulose (BC) as a reinforcing agent. The effects of amino acid types on mechanical and antimicrobial properties are systematically investigated. D-arginine-based hydrogel (D-PCArg) shows the highest tensile strength (220.7 KPa), D-phenylalanine-based hydrogel (D-PCPhe) exhibits the highest elongation at break (1346%), and L-aspartic acid-based hydrogel (L-PCAsp) has the highest elastic modulus (206.9 KPa) and toughness (1.74 MJ m-3). D/L-PCAsp hydrogels demonstrate stronger antibacterial capacity against Escherichia coli and Staphylococcus aureus, and D/L-PCPhe hydrogels possess higher antifungal activity against Cryptococcus neoformans. Moreover, the resultant hydrogels exhibit prominent hemocompatibility and low toxicity, as well as excellent self-healing capabilities (86%) and conductivity (2.8 S m-1). These results indicate that D/L-PCAA hydrogel provides a promise for applications in wound dressings.


Assuntos
Aminoácidos , Antibacterianos , Escherichia coli , Hidrogéis , Líquidos Iônicos , Staphylococcus aureus , Hidrogéis/química , Hidrogéis/farmacologia , Hidrogéis/síntese química , Escherichia coli/efeitos dos fármacos , Aminoácidos/química , Aminoácidos/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/química , Antibacterianos/farmacologia , Antibacterianos/síntese química , Líquidos Iônicos/química , Líquidos Iônicos/farmacologia , Testes de Sensibilidade Microbiana , Antifúngicos/farmacologia , Antifúngicos/química , Antifúngicos/síntese química , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Anti-Infecciosos/síntese química
5.
Cells ; 13(2)2024 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-38247875

RESUMO

Rabies virus (RABV) is a single-stranded negative-sense RNA virus belonging to the Rhabdoviridae family and Lyssavirus genus, which is highly neurotropic and can infect almost all warm-blooded animals, including humans. Autophagy and apoptosis are two evolutionarily conserved and genetically regulated processes that maintain cellular and organismal homeostasis, respectively. Autophagy recycles unnecessary or dysfunctional intracellular organelles and molecules in a cell, whereas apoptosis eliminates damaged or unwanted cells in an organism. Studies have shown that RABV can induce both autophagy and apoptosis in target cells. To advance our understanding of pathogenesis of rabies, this paper reviews the molecular mechanisms of autophagy and apoptosis induced by RABV and the effects of the two cellular events on RABV replication.


Assuntos
Vírus da Raiva , Raiva , Animais , Humanos , Apoptose , Autofagia , Replicação Viral
6.
Adv Mater ; 36(7): e2310237, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38009650

RESUMO

The experimental replicability of highly efficient perovskite solar cells (PSCs) is a persistent challenge faced by laboratories worldwide. Although trace impurities in raw materials can impact the experimental reproducibility of high-performance PSCs, the in situ study of how trace impurities affect perovskite film growth is never investigated. Here, light is shed on the impact of inevitable water contamination in lead iodide (PbI2 ) on the replicability of device performance, mainly depending on the synthesis methods of PbI2 . Through synchrotron-based structure characterization, it is uncovered that even slight additions of water to PbI2 accelerate the crystallization process in the perovskite layer during annealing. However, this accelerated crystallization also results in an imbalance of charge-carrier mobilities, leading to a degradation in device performance and reduced longevity of the solar cells. It is also found that anhydrous PbI2 promotes a homogenous nucleation process and improves perovskite film growth. Finally, the PSCs achieve a remarkable certified power conversion efficiency of 24.3%. This breakthrough demonstrates the significance of understanding and precisely managing the water content in PbI2 to ensure the experimental replicability of high-efficiency PSCs.

7.
Tissue Cell ; 86: 102263, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37979396

RESUMO

The identification and investigation of key molecules involved in the pathogenesis of multiple myeloma (MM) hold paramount clinical significance. This study primarily focuses on elucidating the role of DEPDC1B within the context of MM. Our findings robustly affirm the abundant expression of DEPDC1B in MM tissues and cell lines. Notably, DEPDC1B depletion exerted inhibitory effects on MM cell proliferation and migration while concurrently facilitating apoptosis and G2 cell cycle arrest. These outcomes stand in stark contrast to the consequences of DEPDC1B overexpression. Furthermore, we identified CCNB1 as a putative downstream target, characterized by a co-expression pattern with DEPDC1B, mediating DEPDC1B's regulatory influence on MM. Additionally, our results suggest that DEPDC1B knockdown may activate the p53 pathway, thereby impeding MM progression. To corroborate these in vitro findings, we conducted in vivo experiments that further validate the regulatory role of DEPDC1B in MM and its interaction with CCNB1 and the p53 pathway. Collectively, our research underscores DEPDC1B as a potent promoter in the development of MM, representing a promising therapeutic target for MM treatment. This discovery bears significant implications for future investigations in this field.


Assuntos
Mieloma Múltiplo , Proteína Supressora de Tumor p53 , Humanos , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Mieloma Múltiplo/metabolismo , Apoptose/genética , Transdução de Sinais/genética , Proliferação de Células/genética , Linhagem Celular Tumoral , Ciclina B1/genética , Ciclina B1/metabolismo , Ciclina B1/farmacologia , Proteínas Ativadoras de GTPase/metabolismo
8.
J Neurochem ; 2023 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-38115597

RESUMO

Diosgenin, a natural steroid saponin, holds promise as a multitarget therapeutic for various diseases, including neurodegenerative conditions. Its efficacy in slowing Alzheimer's disease, Parkinson's disease, multiple sclerosis, and stroke progression has been demonstrated. However, the role of diosgenin in anti-epilepsy and its potential connection to the modulation of the intestinal microbiota remain poorly understood. In this study, exogenous diosgenin significantly mitigated pentylenetetrazole (PTZ)-induced seizures, learning and memory deficits, and hippocampal neuronal injury. 16S ribosomal RNA (16S rRNA) sequencing revealed a reversal in the decrease of Bacteroides and Parabacteroides genera in the PTZ-induced mouse epileptic model following diosgenin treatment. Fecal microbiota transplantation (FMT) experiments illustrated the involvement of diosgenin in modulating gut microbiota and providing neuroprotection against epilepsy. Our results further indicated the repression of enteric glial cells (EGCs) activation and the TLR4-MyD88 pathway, coupled with reduced production of inflammatory cytokines in the colonic lumen, and improved intestinal barrier function in epilepsy mice treated with diosgenin or FMT. This study suggests that diosgenin plays a role in modifying gut microbiota, contributing to the alleviation of intestinal inflammation and neuroinflammation, ultimately inhibiting epilepsy progression in a PTZ-induced mouse model. Diosgenin emerges as a potential therapeutic option for managing epilepsy and its associated comorbidities.

9.
Biology (Basel) ; 12(7)2023 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-37508327

RESUMO

Anthocyanin is a class of water-soluble flavonoids found in Chinese bayberry (Morella rubra) that is not only responsible for the variety of colors visible in nature but also has numerous health-promoting benefits in humans. Through comparative transcriptomics, we isolated and identified a transcription factor (TF) of the R2R3-MYB type, MrMYB9, in order to explore the anthocyanin biosynthesis pathway in red and white Chinese bayberries. MrMYB9 transcript was positively correlated with anthocyanin level and anthocyanin biosynthetic gene expression during Chinese bayberry fruit maturation (R-values in the range 0.54-0.84, p < 0.05). Sequence analysis revealed that MrMYB9 shared a similar R2R3 domain with MYB activators of anthocyanin biosynthesis in other plants. MrMYB9 substantially transactivated promoters of anthocyanin biosynthesis-related EBGs (MrCHI, MrF3'H, and MrANS) and LBGs (MrUFGT) upon co-expression of the AtEGL3 gene. Our findings indicated that MrMYB9 may positively modulate anthocyanin accumulation in Chinese bayberry.

10.
Adv Mater ; 35(39): e2304094, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37343137

RESUMO

Mixed-halide perovskites show tunable emission wavelength across the visible-light range, with optimum control of the light color. However, color stability remains limited due to the notorious halide segregation under illumination or an electric field. Here, a versatile path toward high-quality mixed-halide perovskites with high emission properties and resistance to halide segregation is presented. Through systematic in and ex situ characterizations, key features for this advancement are proposed: a slowed and controllable crystallization process can promote achievement of halide homogeneity, which in turn ensures thermodynamic stability; meanwhile, downsizing perovskite nanoparticle to nanometer-scale dimensions can enhance their resistance to external stimuli, strengthening the phase stability. Leveraging this strategy, devices are developed based on CsPbCl1.5 Br1.5 perovskite that achieves a champion external quantum efficiency (EQE) of 9.8% at 464 nm, making it one of the most efficient deep-blue mixed-halide perovskite light-emitting diodes (PeLEDs) to date. Particularly, the device demonstrates excellent spectral stability, maintaining a constant emission profile and position for over 60 min of continuous operation. The versatility of this approach with CsPbBr1.5 I1.5 PeLEDs is further showcased, achieving an impressive EQE of 12.7% at 576 nm.

11.
Front Microbiol ; 14: 1151768, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37180236

RESUMO

The microbial community plays an important role in the biogeochemical cycles in water aquatic ecosystems, and it is regulated by environmental variables. However, the relationships between microbial keystone taxa and water variables, which play a pivotal role in aquatic ecosystems, has not been clarified in detail. We analyzed the seasonal variation in microbial communities and co-occurrence network in the representative areas taking Lake Dongqian as an example. Both pro- and eukaryotic community compositions were more affected by seasons than by sites, and the prokaryotes were more strongly impacted by seasons than the eukaryotes. Total nitrogen, pH, temperature, chemical oxygen demand, dissolved oxygen and chlorophyll a significantly affected the prokaryotic community, while the eukaryotic community was significantly influenced by total nitrogen, ammonia, pH, temperature and dissolved oxygen. The eukaryotic network was more complex than that of prokaryotes, whereas the number of eukaryotic keystone taxa was less than that of prokaryotes. The prokaryotic keystone taxa belonged mainly to Alphaproteobacteria, Betaproteobacteria, Actinobacteria and Bacteroidetes. It is noteworthy that some of the keystone taxa involved in nitrogen cycling are significantly related to total nitrogen, ammonia, temperature and chlorophyll a, including Polaromonas, Albidiferax, SM1A02 and Leptolyngbya so on. And the eukaryotic keystone taxa were found in Ascomycota, Choanoflagellida and Heterophryidae. The mutualistic pattern between pro- and eukaryotes was more evident than the competitive pattern. Therefore, it suggests that keystone taxa could be as bio-indicators of aquatic ecosystems.

12.
Angew Chem Int Ed Engl ; 62(21): e202302184, 2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-36866612

RESUMO

Mixed-halide perovskites are considered the most straightforward candidate to realize blue perovskite light-emitting diodes (PeLEDs). However, they suffer severe halide migration, leading to spectral instability, which is particularly exaggerated in high chloride alloying perovskites. Here, we demonstrate energy barrier of halide migration can be tuned by manipulating the degree of local lattice distortion (LLD). Enlarging the LLD degree to a suitable level can increase the halide migration energy barrier. We herein report an "A-site" cation engineering to tune the LLD degree to an optimal level. DFT simulation and experimental data confirm that LLD manipulation suppresses the halide migration in perovskites. Conclusively, mixed-halide blue PeLEDs with a champion EQE of 14.2 % at 475 nm have been achieved. Moreover, the devices exhibit excellent operational spectral stability (T50 of 72 min), representing one of the most efficient and stable pure-blue PeLEDs reported yet.

14.
Nanoscale ; 15(8): 3713-3729, 2023 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-36723157

RESUMO

Perovskite quantum dots are a competitive candidate for next-generation solar cells owing to their superior phase stability and multiple exciton generation effects. However, given the voltage loss in perovskite quantum dot solar cells (PQDSCs) is mainly caused by various surface and interfacial defects and the energy band mismatch in the devices, tremendous achievements have been made to mitigate the Voc loss of PQDSCs. Herein, we elucidate the potential threats that hinder the high Voc of PQDSCs. Then, we summarize recent progress in minimizing open-circuit voltage (Voc) loss, including defect manipulation and device optimization, based on band-alignment engineering. Finally, we attempt to shed light on the methodologies used to further improve the performance of PQDSCs.

15.
BMC Endocr Disord ; 23(1): 21, 2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36691016

RESUMO

BACKGROUND: To evaluate the endocrine hormone and metabolic indices in postmenopausal women with euthyroid and mild subclinical hypothyroidism after menopause hormone therapy (MHT). METHODS: A retrospective study of 587 postmenopausal women receiving MHT was conducted. Median (25-75th percentile) age was 52 (49-54) years. According to thyroid stimulating hormone (TSH) levels at initial diagnosis, the patients were divided into three groups: I (euthyroid with low normal TSH range, n = 460), II (euthyroid with upper normal TSH range, n = 106) and III (mild subclinical hypothyroidism, n = 21). After a continuous oral MHT regimen using the same estradiol potency for 6-18 month cycles, serum endocrine hormone and metabolic indices were reassessed. RESULTS: Compared with baseline, serum TSH levels in groups I and II significantly changed but all values were within the normal range. No significant difference was observed in serum TSH levels in group III. After treatment, all serum free tri-iodothyronine and free thyroxine levels were within the normal range. Serum total cholesterol, triglyceride, fasting plasma glucose, fasting insulin levels and homeostasis model assessment of insulin resistance index had significantly decreased in group I. There were no significant differences in all observed lipid and glucose parameters in group III, before and after treatment. CONCLUSION: MHT did not affect thyroid function in postmenopausal women with euthyroid and mild subclinical hypothyroidism. MHT led to an improvement in lipid and glucose indicators in euthyroid women with low normal TSH range.


Assuntos
Hipotireoidismo , Tireotropina , Humanos , Feminino , Pessoa de Meia-Idade , Estudos Retrospectivos , Pós-Menopausa , Hipotireoidismo/tratamento farmacológico , Triglicerídeos , Glucose , Terapia de Reposição Hormonal , Tiroxina
16.
Menopause ; 30(2): 122-127, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36696635

RESUMO

OBJECTIVE: Menopausal transition has been known to be associated with the loss of muscle mass. However, muscle health in women with premature menopause, that is, premature ovarian insufficiency (POI), remains unclear. We aimed to investigate and compare muscle mass parameters and the prevalence of low muscle mass between patients with spontaneous POI and healthy controls. METHODS: In this cross-sectional study, 59 women with spontaneous POI and 57 premenopausal controls with normal ovarian function were enrolled at the Women's Hospital, Zhejiang University School of Medicine (Hangzhou, China) from June 17, 2020, to August 20, 2021. Muscle mass parameters were measured by dual-energy x-ray absorptiometry, and low muscle mass was diagnosed using the Asian Working Group for Sarcopenia criteria. In addition, participants provided their sociodemographic data, menstrual and reproductive history, lifestyle factors, and medical history. Multivariate linear regression analysis was conducted. RESULTS: Muscle mass parameters, including appendicular skeletal muscle mass (ASM), ASM/height2, ASM/weight, ASM/body mass index, total skeletal muscle mass (TSM), and TSM/weight, were significantly lower in women with POI as compared with healthy controls (ASM: 14.62 ± 2.08 vs 15.97 ± 1.78, P < 0.001; ASM/height2: 5.71 ± 0.64 vs 6.15 ± 0.62, P < 0.001; ASM/weight: 0.27 [0.25, 0.28] vs 0.28 [0.27, 0.29], P = 0.002; ASM/BMI: 0.68 ± 0.07 vs 0.73 ± 0.06, P = 0.001; TSM: 33.85 ± 4.08 vs 36.43 ± 3.56, P < 0.001; TSM/weight: 0.63 [0.59, 0.65] vs 0.64 [0.61, 0.67], P = 0.02). The prevalence of low muscle mass in POI patients was significantly higher than that in controls (32.20% vs 8.77%, χ2 = 9.70, P = 0.002). Furthermore, multivariate linear regression analyses demonstrated that POI status was an independent risk factor for ASM (ß = -1.13; 95% CI, -1.62 to -0.65), ASM/height2 (-0.35, -0.47 to -0.22), ASM/weight (-0.01, -0.02 to -0.009), ASM/BMI (-0.05, -0.07 to -0.02), TSM (-2.16, -3.14 to -1.17), and TSM/weight (-0.03, -0.04 to -0.02). CONCLUSIONS: Women with POI exhibit significant loss of muscle mass as compared with healthy controls. Early diagnosis and long-term health management in POI patients are important.


Assuntos
Menopausa Precoce , Insuficiência Ovariana Primária , Sarcopenia , Humanos , Feminino , Menopausa Precoce/fisiologia , Estudos Transversais , Insuficiência Ovariana Primária/complicações , Sarcopenia/epidemiologia , Músculos , Músculo Esquelético/fisiologia
17.
Maturitas ; 167: 46-52, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36306666

RESUMO

OBJECTIVE: To identify occupational hazards associated with earlier onset of natural menopause. STUDY DESIGN: A national cross-sectional study was conducted to explore the reproductive health of Chinese female workers. The final sample size was 17,948. MAIN OUTCOME MEASURES: Participants completed a self-report instrument that recorded working conditions, chemical and physical agents in the occupational environment, socioeconomic factors, lifestyle, reproductive history, and occupational information. A Cox regression model was used to examine the association between each occupational hazard and onset of menopause. RESULTS: Abnormal workload (19.31 %), aromatic compounds (7.95 %), and noise (24.94 %) were the three most frequently self-reported occupational hazards in the three categories of working conditions, chemical agents, and physical agents, respectively. Abnormal workload (HR = 1.133, p = 0.038), noise (HR = 1.233, p < 0.001), and heat stress (HR = 1.178, p = 0.041) were associated with earlier age at natural menopause in the analyses of each hazard, after adjustment. Only noise (HR = 1.187, p = 0.003) remained statistically significant after including all possible occupational hazards. CONCLUSIONS: In a national survey of 17,948 female workers, this study investigated the association of age at natural menopause with multiple occupational hazards, some of which have not been addressed. Occupational noise was identified as a risk factor for reproductive senescence for the first time. However, further research is needed to confirm our findings.


Assuntos
Envelhecimento , Menopausa , Humanos , Feminino , Estudos Transversais , Fatores de Risco , Modelos de Riscos Proporcionais
18.
Food Chem ; 399: 133997, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36037687

RESUMO

The effect of hydrogen-rich water (HRW) treatment on softening, cell wall components and cell wall metabolic genes in okras after harvest was studied. The results showed that HRW treatment could maintain fruit firmness and delay softening, thereby prolonging shelf life in okras during storage. The treated okras displayed significantly lower levels water- and chelate-soluble pectins while higher contents of Na2CO3-soluble pectin, hemicellulose and cellulose. The cell wall biosynthesis was maintained by HRW treatment via up-regulating genes involved in biosynthesis of pectin, hemicellulose and cellulose at the beginning of storage. On the contrary, the treatment could inhibit the cell wall disassembly due to the down-regulation of numerous cell wall degradative genes including AePME, AeGAL and AeCX at the end of storage. Taken together, our results suggested that HRW treatment delayed softening and extended shelf life in postharvest okras through modifying cell wall biosynthesis and disassembly at different times of storage.


Assuntos
Abelmoschus , Frutas , Abelmoschus/metabolismo , Parede Celular/metabolismo , Celulose/metabolismo , Frutas/metabolismo , Hidrogênio/farmacologia , Pectinas/metabolismo , Água/metabolismo
19.
Front Plant Sci ; 13: 1059979, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36570953

RESUMO

Peach fruit was treated with 5 mM γ-aminobutyric acid (GABA) to further investigate the mechanism by which GABA induced chilling tolerance. Here, we found that GABA not only inhibited the occurrence of chilling injury in peach fruit during cold storage but also maintained fruit quality. Most of the ascorbic acid (AsA) and glutathione (GSH) biosynthetic genes were up-regulated by GABA treatment, and their levels were increased accordingly, thus reducing chilling damage in treated peaches. Meanwhile, the increased transcript of genes in the AsA-GSH cycle by GABA treatment was also related to the induced tolerance against chilling. GABA treatment also increased the expression levels of several candidate ERF transcription factors involved in AsA and GSH biosynthesis. In conclusion, our study found that GABA reduced chilling injury in peach fruit during cold storage due to the higher AsA and GSH contents by positively regulating their modifying genes and candidate transcription factors.

20.
Nature ; 612(7941): 679-684, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36543955

RESUMO

Perovskite light-emitting diodes (PeLEDs) with an external quantum efficiency exceeding 20% have been achieved in both green and red wavelengths1-5; however, the performance of blue-emitting PeLEDs lags behind6,7. Ultrasmall CsPbBr3 quantum dots are promising candidates with which to realize efficient and stable blue PeLEDs, although it has proven challenging to synthesize a monodispersed population of ultrasmall CsPbBr3 quantum dots, and difficult to retain their solution-phase properties when casting into solid films8. Here we report the direct synthesis-on-substrate of films of suitably coupled, monodispersed, ultrasmall perovskite QDs. We develop ligand structures that enable control over the quantum dots' size, monodispersity and coupling during film-based synthesis. A head group (the side with higher electrostatic potential) on the ligand provides steric hindrance that suppresses the formation of layered perovskites. The tail (the side with lower electrostatic potential) is modified using halide substitution to increase the surface binding affinity, constraining resulting grains to sizes within the quantum confinement regime. The approach achieves high monodispersity (full-width at half-maximum = 23 nm with emission centred at 478 nm) united with strong coupling. We report as a result blue PeLEDs with an external quantum efficiency of 18% at 480 nm and 10% at 465 nm, to our knowledge the highest reported among perovskite blue LEDs by a factor of 1.5 and 2, respectively6,7.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...