Light-emitting diode

发光二极管
  • 文章类型: Journal Article
    明亮的光线影响人类的昼夜节律系统,因此夜间暴露于明亮的光线可以抑制褪黑激素的分泌,早晨暴露在强光下可以防止夜间光诱导的褪黑激素抑制。晨光的预防作用可能会削弱调节昼夜节律系统的固有光敏性视网膜神经节细胞(ipRGC)的光敏感性的先前历史。在这项研究中,我们评估了在昏暗和明亮的日光条件下对红色和蓝色闪烁光的视网膜电图(ERG)反应.11名健康女性在昏暗和明亮的白天条件下暴露于33Hz闪烁的红色或蓝色光期间进行了ERG测量。我们平均了触发信号数据的50个闪烁光脉冲的ERG波。我们通过计算波峰和波底之间的差异获得了信号平均ERG的幅度。尽管ERG波的振幅没有明显的暗光和亮光差异,亮光条件下闪烁蓝光的ERG振幅明显低于暗光条件下闪烁蓝光的ERG振幅。在这项研究中,蓝光主要刺激ipRGC和S-锥。由于S锥可能对光线适应的33Hz闪烁ERG结果贡献最小,我们的研究结果表明,白天的强光会减弱人类ipRGC的敏感性。
    Bright light impacts the human circadian system such that exposure to bright light at night can suppress melatonin secretion, and exposure to bright light in the morning prevents light-induced melatonin suppression at night. The preventive effect of morning light may attenuate the prior history of light sensitivity of intrinsically photosensitive retinal ganglion cells (ipRGCs) that regulate the circadian system. In this study, we evaluated electroretinogram (ERG) responses to red and blue flickering lights following dim and bright daylight conditions. Eleven healthy females underwent ERG measurements during exposure to 33 Hz flickering red or blue light under dim and bright daytime conditions. We averaged ERG waves for 50 flickering light pulses of the trigger signal data. We obtained the amplitude of the signal-averaged ERG by calculating the difference between the waves\' peaks and bottoms. Although there was no significant dim and bright light difference in the amplitude of ERG waves, the ERG amplitude to flickering blue light under the bright light condition was significantly lower than to flickering blue light under the dim light condition. In this study, blue light stimulated mainly ipRGCs and S-cones. Since S-cones may contribute minimally to the light-adapted 33 Hz flicker ERG results, our findings suggest that bright light during the daytime attenuates the sensitivity of human ipRGCs.
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  • 文章类型: Journal Article
    高清近眼显示技术具有极近的视距,对尺寸提出了更高的要求,性能,和发光像素器件阵列。基于金属卤化物钙钛矿材料优异的光电性能,钙钛矿发光二极管(PeLED)具有较高的光电转换效率,可调节的发射光谱,和优异的电荷转移特性,展示了作为下一代光源的巨大前景。尽管有潜力,钙钛矿在光刻胶中的溶解度为传统的微/纳米加工技术提供了障碍,导致器件尺寸通常超过50μm。这种限制阻碍了钙钛矿基组件的进一步小型化。在这里,我们提出了一种平面结构的PeLED器件,其可以实现具有<2μm的单像素器件尺寸和大约3s的发光寿命的微型发光二极管。这是通过制造图案化衬底并通过自掺杂效应调节钙钛矿中的离子分布以形成PN结来实现的。这一突破克服了钙钛矿-光刻胶不相容的技术挑战,阻碍了钙钛矿材料在微/纳米光电器件中的发展。这项研究取得的进展为在微/纳米光电器件领域内发展PeLED开辟了有希望的途径。
    High-definition near-eye display technology has extremely close sight distance, placing a higher demand on the size, performance, and array of light-emitting pixel devices. Based on the excellent photoelectric performance of metal halide perovskite materials, perovskite light-emitting diodes (PeLEDs) have high photoelectric conversion efficiency, adjustable emission spectra, and excellent charge transfer characteristics, demonstrating great prospects as next-generation light sources. Despite their potential, the solubility of perovskite in photoresist presents a hurdle for conventional micro/nano processing techniques, resulting in device sizes typically exceeding 50 μm. This limitation impedes the further downsizing of perovskite-based components. Herein, we propose a plane-structured PeLED device that can achieve microscale light-emitting diodes with a single pixel device size < 2 μm and a luminescence lifetime of approximately 3 s. This is accomplished by fabricating a patterned substrate and regulating ion distribution in the perovskite through self-doping effects to form a PN junction. This breakthrough overcomes the technical challenge of perovskite-photoresist incompatibility, which has hindered the development of perovskite materials in micro/nano optoelectronic devices. The strides made in this study open up promising avenues for the advancement of PeLEDs within the realm of micro/nano optoelectronic devices.
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  • 文章类型: Journal Article
    短波红外(SWIR)发光二极管(LED)已成为光通信等多种应用的有前途的技术,生物医学成像,监视,和机器视觉。胶体量子点(QD)由于其溶液可加工性而对SWIRLED特别有吸引力,与柔性基板的兼容性,和可调吸收和发光。然而,大多数SWIR发射量子点中有毒元素或贵金属的存在会带来健康,环境,和成本挑战。在这种情况下,CuInS2(CIS)量子点是众所周知的低毒性,具有成本效益的制造,和SWIR发光能力。然而,迄今为止,CISQD尚未直接用于制造SWIRLED,这是由于粒子稳定性低,低效的电荷载流子复合,以及集成到LED器件后的显着蓝移发光。为了应对挑战,我们提出了一种使用ZnI2作为化学添加剂的双钝化策略,以增强纯CISQD的光学性能和在LED器件实现时的电荷载流子复合。所得的基于CIS-QD的LED表现出稳定的SWIR电致发光(EL)峰(超过1000nm),具有高EL辐射度,并且在SWIR区域具有记录的外部量子效率。我们的研究代表了SWIR-QLED技术向前迈出的重要一步,为高性能的发展提供了一条途径,低成本,和无毒的SWIR光源。
    Short-wave infrared (SWIR) light-emitting diodes (LEDs) have emerged as promising technologies for diverse applications such as optical communication, biomedical imaging, surveillance, and machine vision. Colloidal quantum dots (QDs) are particularly attractive for SWIR LEDs due to their solution processability, compatibility with flexible substrates, and tunable absorption and luminescence. However, the presence of toxic elements or precious metals in most SWIR-emitting QDs poses health, environmental, and cost challenges. In this context, CuInS2 (CIS) QDs are known for low toxicity, cost-effective fabrication, and SWIR-light emitting capability. However, CIS QDs have not yet been directly utilized to fabricate SWIR LEDs to date, which is due to low particle stability, inefficient charge carrier recombination, and significantly blue-shifted luminescence after integrating into LED devices. To address challenges, we propose a dual-passivation strategy using ZnI2 as a chemical additive to enhance both the optical property of plain CIS QDs and charge carrier recombination upon LED device implementation. The resulting CIS-QD-based LEDs exhibit a stable SWIR electroluminescence (EL) peak (over 1000 nm) with a high EL radiance and a record external quantum efficiency in the SWIR region. Our study represents a significant step forward in SWIR-QLED technology, offering a pathway for the development of high-performance, low-cost, and nontoxic SWIR light sources.
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  • 文章类型: Journal Article
    这项研究调查了以发光二极管(LED)为光源的牙科实验室聚合单元的有用性。固化深度(n=15),通过五个牙科实验室聚合单元(LEDCureMaster,闪烁LED,α-LightV,α-LightII,和HyperLII)。通过单因素方差分析和Tukey检验或非参数检验进行统计学分析。比较光源的固化深度表明,金属卤化物具有最高的价值,其次是具有相似值的LED组,和最低值的卤素灯。用三个LED实验室聚合单元聚合的复合材料样品的吸水率和溶解度在ISO推荐的限值内。
    This study investigated the usefulness of a dental laboratory polymerization unit with light-emitting diode (LED) as a light source. The depth of cure (n=15), water absorption and solubility (n=9) of two indirect composite materials (Cesead N and Solidex Hardura) were evaluated by five dental laboratory polymerization units (LED Cure Master, Twinkle LED, α-Light V, α-Light II, and Hyper LII). Statistical analysis was performed by one-way ANOVA and Tukey test or non-parametric tests. Comparison of light sources for curing depth showed that metal halide had the highest value, followed by the LED group with similar values, and halogen lamps with the lowest value. The water absorption and solubility of the composite specimens polymerized with the three LED laboratory polymerization units were within the ISO recommended limit.
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  • 文章类型: Journal Article
    在这项研究中,通过制备发光二极管(LED),研究了缺陷对氮掺杂ZnO纳米颗粒(NPs)受体性质的影响。通过电弧放电气体中蒸发法合成了氮掺杂的ZnONP,并在800°C的氧气和氮气气氛中进行了后退火。通过X射线衍射对退火后的ZnONPs进行了表征,扫描电子显微镜,拉曼光谱,和光致发光光谱。发现氮掺杂的ZnONP在氮环境中的退火增加了锌空位的数量,而在氧环境中退火则由于氮解吸而增加了氧空位的数量。用氧退火的NP制造的LED的输出特性下降,而那些氮退火的NP显著提高。从这些结果来看,在实际的pn结器件中,首次证实了锌空位对ZnONP中受体形成的贡献。
    In this study, the effect of defects on the acceptor properties of nitrogen-doped ZnO nanoparticles (NPs) was investigated through the fabrication of light-emitting diodes (LEDs). Nitrogen-doped ZnO NPs were synthesized by an arc discharge in-gas evaporation method and post-annealed at 800 °C in an oxygen and nitrogen atmosphere. The annealed ZnO NPs were characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and photoluminescence spectroscopy. It was found that the annealing of nitrogen-doped ZnO NPs in a nitrogen environment increased the number of zinc vacancies, while annealing in an oxygen environment increased the number of oxygen vacancies due to nitrogen desorption. The output characteristics of LEDs fabricated with oxygen-annealed NPs were degraded, while those with nitrogen-annealed NPs were significantly improved. From these results, the contribution of zinc vacancies to acceptor formation in ZnO NPs was confirmed for the first time in actual pn junction devices.
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  • 文章类型: Journal Article
    最近的研究表明,蓝色发光二极管(LED)灯具有抗肿瘤作用,表明在癌症治疗中使用可见光的可能性。然而,蓝光照射对肿瘤微环境中细胞的影响,包括肿瘤相关巨噬细胞(TAMs),是未知的。这里,将THP-1细胞在HCT-116细胞的条件培养基(CM)中培养以制备TAM。将TAM分为LED照射组和对照组。然后,研究了蓝光LED照射对TAM激活的影响。与对照组相比,LED照射的TAM中M2巨噬细胞标志物CD163和CD206的表达水平显着降低。而对照TAM-CM可以诱导HCT-116细胞迁移,在LED照射的TAM-CM中培养的细胞中未观察到这些作用。在LED照射的TAM中,血管内皮生长因子(VEGF)的分泌受到显着抑制。在TAM-CM培养的HCT-116细胞中,PD-L1的表达上调,但在LED照射的TAM-CM培养的细胞中,PD-L1的表达减弱。在体内模型中,F4/80和CD163的蛋白表达水平,它们是TAM标记,在LED暴露组中减少。这些结果表明,蓝色LED光可能对TAM具有抑制作用,以及对结肠癌细胞的抗肿瘤作用。
    Recent studies have shown that blue light-emitting diode (LED) light has anti-tumor effects, suggesting the possibility of using visible light in cancer therapy. However, the effects of blue light irradiation on cells in the tumor microenvironment, including tumor-associated macrophages (TAMs), are unknown. Here, THP-1 cells were cultured in the conditioned medium (CM) of HCT-116 cells to prepare TAMs. TAMs were divided into LED-irradiated and control groups. Then, the effects of blue LED irradiation on TAM activation were examined. Expression levels of M2 macrophage markers CD163 and CD206 expression were significantly decreased in LED-irradiated TAMs compared with the control group. While control TAM-CM could induce HCT-116 cell migration, these effects were not observed in cells cultured in TAM-CM with LED irradiation. Vascular endothelial growth factor (VEGF) secretion was significantly suppressed in LED-exposed TAMs. PD-L1 expression was upregulated in HCT-116 cells cultured with TAM-CM but attenuated in cells cultured with LED-irradiated TAM-CM. In an in vivo model, protein expression levels of F4/80 and CD163, which are TAM markers, were reduced in the LED-exposed group. These results indicate that blue LED light may have an inhibitory effect on TAMs, as well as anti-tumor effects on colon cancer cells.
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  • 文章类型: Journal Article
    研究的目的是评估两种半透明树脂复合材料系统,用于定制具有发光二极管(LED)固化单元的光聚合纤维柱,其在24小时和6个月时使用常规水泥进行粘合。
    这是一项体外实验研究。
    制备40根并分成四组(n=10):ZV-Z350树脂和LEDValo;ZR-Z350树脂和LED半径-Cal;OV-Opallis树脂和LEDValo;和OR-Opallis树脂和LED半径-Cal。纤维桩是定制的,并用常规树脂水泥胶结,并通过两种不同的来源进行光活化。
    对数据进行了双向方差分析和Tukey的事后检验(P=0.05)。根据后空间的三分之一中发生的频率来描述有关粘合失效模式的数据。
    在24小时和6个月时,组间的粘结强度相似,无论分析后空间如何(P>0.05)。粘合剂失效类型4在所有三分之一中最常见。
    使用Z350和Opallis定制纤维桩对粘合强度和粘合失效模式具有相同的作用,无论用于光聚合的LED固化单元。
    UNASSIGNED: The objective of the study was to evaluate two translucent resin composite systems for customizing light-polymerized fiber posts with light-emitting diode (LED) curing units regarding adhesion using conventional cement at 24 h and 6 months.
    UNASSIGNED: This was an experimental in vitro study.
    UNASSIGNED: Forty roots were prepared and divided into four groups (n = 10): ZV-Z350 resin and LED Valo; ZR-Z350 resin and LED Radii-Cal; OV-Opallis resin and LED Valo; and OR-Opallis resin and LED Radii-Cal. The fiber post was customized and cemented with conventional resin cement and was photoactivated by two different sources.
    UNASSIGNED: The data were subjected to two-way ANOVA and Tukey\'s post hoc tests (P = 0.05). The data regarding the pattern of adhesive failures were described in terms of the frequency of occurrence in each third of the postspace.
    UNASSIGNED: Both at 24 h and 6 months, bond strength among groups was similar, regardless of the analyzed postspace 3rd (P > 0.05). Adhesive failure Type 4 was the most frequent in all thirds.
    UNASSIGNED: Customizing the fiber post with Z350 and Opallis has the same effect on bond strength and adhesive failure pattern, regardless of the LED curing units used for photopolymerization.
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  • 文章类型: Journal Article
    由于量子限制效应,减小钙钛矿纳米晶体尺寸会增加辐射复合,但也增加了俄歇复合率,这导致电致发光器件的发射层中的载流子不平衡。这里,我们通过增加激子有效质量而不影响大小来克服这种权衡,这是通过甲脒溴化铅钙钛矿纳米晶体的痕量Cd2+掺杂来实现的。在俄歇复合率几乎不变的情况下,由于掺杂引起的[BX6]4-八面体的轻微变形,我们观察到激子结合能增加了〜2.7倍。因此,获得了具有96%的光致发光量子产率的明亮的彩色饱和绿色钙钛矿纳米晶体。基于这些纳米晶体的发光器件达到了29.4%的高外部量子效率(EQE),相当于123cdA-1的电流效率,并显示出显著提高的器件寿命,对于以534nm为中心的电致发光峰,其颜色饱和的绿色发射的窄带宽为22nm,国际委员会的Eclairage坐标为(0.20,0.76),从而完全符合宽色域显示器的最新标准。
    Decreasing perovskite nanocrystal size increases radiative recombination due to the quantum confinement effect, but also increases the Auger recombination rate which leads to carrier imbalance in the emitting layers of electroluminescent devices. Here, we overcome this trade-off by increasing the exciton effective mass without affecting the size, which is realized through the trace Cd2+ doping of formamidinium lead bromide perovskite nanocrystals. We observe an ~2.7 times increase in the exciton binding energy benefiting from a slight distortion of the [BX6]4- octahedra caused by doping in the case of that the Auger recombination rate is almost unchanged. As a result, bright color-saturated green emitting perovskite nanocrystals with a photoluminescence quantum yield of 96 % are obtained. Cd2+ doping also shifts up the energy levels of the nanocrystals, relative to the Fermi level so that heavily n-doped emitters convert into only slightly n-doped ones; this boosts the charge injection efficiency of the corresponding light-emitting diodes. The light-emitting devices based on those nanocrystals reached a high external quantum efficiency of 29.4 % corresponding to a current efficiency of 123 cd A-1, and showed dramatically improved device lifetime, with a narrow bandwidth of 22 nm and Commission Internationale de I\'Eclairage coordinates of (0.20, 0.76) for color-saturated green emission for the electroluminescence peak centered at 534 nm, thus being fully compliant with the latest standard for wide color gamut displays.
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  • 文章类型: Journal Article
    葡萄酒色斑(PWS)胎记是先天性毛细血管畸形,发生在0.3%〜0.5%的新生儿中。血泊芬介导的血管作用光动力疗法(血泊芬PDT)是治疗PWS的新兴选择。这项体内研究旨在比较激光和发光二极管(LED)作为HemoporfinPDT的光源。使用鸡wattles作为动物模型。在相同剂量下,将Hemoporfin与KTP激光或532nm的LED光源组合后,评估颜色和组织病理学变化。两种PDT方法均可引起明显的血管损伤和颜色漂白。尽管激光的使用导致了更大的血管间隙,LED在光束轮廓和组织反应中均显示出更均匀的分布,并表现出更好的安全性。这项体内研究表明,LED是较大PWS病变的有利选择。
    Port-wine stain (PWS) birthmarks are congenital capillary malformations occurring in 0.3 %∼0.5 % of newborns. Hemoporfin-mediated vascular-acting photodynamic therapy (Hemoporfin PDT) is an emerging option for treating PWS. This in vivo study aimed to compare laser and light-emitting diodes (LED) as light source for Hemoporfin PDT. Chicken wattles were used as the animal model. Color and histopathological changes were evaluated after combining Hemoporfin with KTP laser or LED light source of 532 nm at the same doses. Both PDT approaches could induce significant vascular injury and color bleaching. Although the use of the laser resulted in a greater vascular clearance, the LED showed more uniform distribution both in the beam profiles and tissue reaction and exhibited better safety. This in vivo study suggests that the LED is a favorable choice for larger PWS lesion.
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  • 文章类型: Journal Article
    背景:这项研究旨在比较低水平二极管激光(LLDL)和红色发光二极管(LED)对人牙髓干细胞(hDPSC)和成骨/牙源性分化的存活的影响。方法和材料:在这项离体实验研究中,实验组在成骨培养基中接受LLDL(4J/cm2能量密度)和红色LED的照射。在24和48小时(n=9)后使用甲基噻唑基四唑(MTT)测定评估hDPSC的存活。使用茜素红染色(ARS;三次重复)进行成骨/牙源性分化的评估。在两个时间点进行成骨和牙源性基因表达的研究,特别是24和48小时(n=12)。利用实时逆转录聚合酶链反应(RT-PCR)进行该分析。使用SPSS版本24在每个时间点比较各组。为了分析数据,Mann-WhitneyU测试,方差分析,Tukey\'stest,采用t检验。结果:MTT法显示LLDL显著降低hDPSCs48h后的存活率,与其他组相比(p<0.05)。ARS的定性结果表明,LLDL和红色LED增加了hDPSCs的成骨分化。LLDL和红色LED均上调成骨/牙源性基因的表达,包括骨唾液蛋白(BSP),碱性磷酸酶(ALP),牙本质基质蛋白1(DMP1),和牙本质唾液酸糖蛋白(DSPP),在hDPSC中。LLDL组表现出更高水平的基因上调(p<0.0001)。结论:hDPSC细胞存活率降低,尽管成骨/牙源性活性增加。临床相关性:介绍再生牙髓治疗中的非侵入性方法。
    Background: This investigation set out to compare the impacts of low-level diode laser (LLDL) and red light-emitting diode (LED) on the survival of human dental pulp stem cells (hDPSCs) and osteogenic/odontogenic differentiation. Methods and materials: In this ex vivo experimental study, the experimental groups underwent the irradiation of LLDL (4 J/cm2 energy density) and red LED in the osteogenic medium. Survival of hDPSCs was assessed after 24 and 48 h (n = 9) using the methyl thiazolyl tetrazolium (MTT) assay. The assessment of osteogenic/odontogenic differentiation was conducted using alizarin red staining (ARS; three repetitions). The investigation of osteogenic and odontogenic gene expression was performed at two time points, specifically 24 and 48 h (n = 12). This analysis was performed utilizing real-time reverse-transcription polymerase chain reaction (RT-PCR). The groups were compared at each time point using SPSS version 24. To analyze the data, the Mann-Whitney U test, analysis of variance, Tukey\'s test, and t-test were utilized. Results: The MTT assay showed that LLDL significantly decreased the survival of hDPSCs after 48 h, compared with other groups (p < 0.05). The qualitative results of ARS revealed that LLDL and red LED increased the osteogenic differentiation of hDPSCs. LLDL and red LED both upregulated the expression of osteogenic/odontogenic genes, including bone sialoprotein (BSP), alkaline phosphatase (ALP), dentin matrix protein 1 (DMP1), and dentin sialophosphoprotein (DSPP), in hDPSCs. The LLDL group exhibited a higher level of gene upregulation (p < 0.0001). Conclusions: The cell survival of hDPSCs was reduced, despite an increase in osteogenic/odontogenic activity. Clinical relevance: Introduction of noninvasive methods in regenerative endodontic treatments.
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