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Effect of Excitation Wavelength on Optical Performances of Quantum-Dot-Converted Light-Emitting Diode
摘要： Light-emitting diode (LED) combined with quantum dots (QDs) is an important candidate for next-generation high-quality semiconductor devices. However, the effect of the excitation wavelength on their optical performance has not been fully explored. In this study, green and red QDs are applied to LEDs of different excitation wavelengths from 365 to 455 nm. The blue light is recommended for exciting QDs from the perspective of energy utilization. However, QD LEDs excited at 365 nm have unique advantages in eliminating the original peaks from the LED chip. Moreover, the green or red light excited by ultraviolet light has an advantage in colorimetry. Even for the 455 nm LED with the highest QD concentration at 7.0 wt%, the color quality could not compete with the 365 nm LED with the lowest QD concentration at 0.2 wt%. A 117.5% (NTSC1953) color gamut could be obtained by the 365 nm-excited RGB system, which is 32.6% higher than by the 455 nm-excited solution, and this can help expand the color gamut of LED devices. Consequently, this study provides an understanding of the properties of QD-converted LEDs under different wavelength excitations, and offers a general guide to selecting a pumping source for QDs.
关键词： excitation wavelength,colorimetry,quantum dots,light-emitting diode
更新于2025-11-19 16:46:39
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A gadolinium(III)-porphyrin based coordination polymer for colorimetric and fluorometric dual mode determination of ferric ions
摘要： A coordination polymer (CP) based nanoprobe is described for colorimetric and fluorometric (dual mode) determination of ferric ion. The method is making use of a nanosized Gd(III)?5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin coordination polymer that was prepared by a single-step hydrothermal procedure. The nanoprobe is monodisperse and has uniform size and good water solubility. It also exhibits strong fluorescence and magnetic resonance response. On exposure to Fe(III), the color of the solution changes from red to brown as the concentration of Fe(III) exceed 5 μM. Similarly, the red fluorescence of the probe (with excitation/emission peaks at 420/675 nm) decreases as concentrations of Fe(III) increase from 0.5 to 100 μM. The limit of detection is 98 nM in the fluorometric mode. The assay was applied to the determination of Fe(III) in fetal bovine serum samples.
关键词： Fluorometry,Metal-organic compound,Fe3+ detection,Colorimetry,Gd-coordinated
更新于2025-11-14 17:04:02
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Free-label dual-signal responsive optical sensor by combining resonance Rayleigh scattering and colorimetry for sensitive detection of glutathione based on ultrathin MnO2 nanoflakes
摘要： Glutathione (GSH) plays a critical role in the living system and its abnormalities are closely associated with numerous clinical diseases. Thus, monitoring and detecting the content of GSH in the living system is still of great importance. Herein, a novel dual-signal responsive optical sensor is developed by using resonance Rayleigh scattering (RRS) and colorimetry for sensitive detection of GSH. In this sensor, MnO2 nanoflakes are used as both GSH recognizer and signal transducer of RRS and colorimetry. The solution of MnO2 nanoflakes shows strong RRS and absorption signals because MnO2 nanoflakes possess a large surface area and high molar extinction coefficient. However, MnO2 can be reduced to Mn2+ and MnO2 nanoflakes can be etched to small nanoparticles by GSH, causing both the RRS and absorption signals to decrease. Based on the change of RRS signal and absorbance of MnO2 nanoflakes, a novel dual-signal responsive optical sensor is successfully constructed to detect the content of GSH. The as-developed optical sensor toward GSH presents a favorable sensitivity with a detection limit of 0.033 and 0.67 μM for RRS and colorimetry, respectively. Furthermore, the as-developed approach is straightforward, quickly responsive, free-label, and cost-effective. More significantly, this method combines the advantages of RRS and colorimetry for the detection of GSH. Beyond this, the proposed RRS method has also been successfully utilized to detect the content of GSH in glutathione injection samples.
关键词： Glutathione,Resonance Rayleigh scattering,MnO2 nanoflakes,Colorimetry,Dual-signal
更新于2025-11-14 17:04:02
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Plasmonic Colorimetric Biosensor for Visual Detection of Telomerase Activity Based on Horseradish Peroxidase-Encapsulated Liposomes and Etching of Au Nanobipyramids
摘要： Telomerase aberrant activation is a critical feature in the vast majority of cancers. To visualize telomerase expression level in tumor cells, we developed a plasmonic colorimetric sensor for highly sensitive detection of telomerase activity by integrating an excellent etching substrate Au nanobipyramids (Au NBPs) with a liposome-based signal amplification strategy. Upon telomerase-triggered extension, the telomerase activity was converted into the amount of the attached horseradish peroxidase-encapsulated liposomes (HRP-Ls) on the surfaces of magnetic beads. Afterwards, HRP was liberated from the liposomes following the addition of H2O2-3,3′,5,5′-tetramethylbenzidine sulfate (TMB) substrate, and then the oxidation reaction between H2O2 and TMB was initiated to form TMB2+. The morphological evolution of Au NBPs relied on the TMB2+-mediated etching reaction, which gave rise to tremendous localized surface plasmon resonance (LSPR) responses and concomitant tonality transitions. Benefiting from cascaded signal amplification capacity of HRP-Ls and the intriguing optical properties of Au NBPs, an impressive sensitivity toward telomerase was obtained with detection limits equivalent to 1 HeLa cell for LSPR peak measurement and a visual detection limit of 20 HeLa cells. Furthermore, a facile and portable kit was fabricated for visual evaluation of telomerase activity in different cell lines.
关键词： Plasmonic colorimetry,Au nanobipyramids,Telomerase,Liposome-based amplification,Multicolor visual detection
更新于2025-11-14 17:04:02
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Modelling the effects of inter-observer variation on colour rendition
摘要： The colour rendition characteristics of light sources are quantified with measures based on CIE standard observers, which are reasonable representations of population averages. However, even among people with normal colour vision, the natural range of variation in colour sensitivity means any individual may see something different than the standard observer. Modelling results quantify the effects of these inter-observer differences on colour rendition measures defined by IES TM-30-15. In general, inter-observer differences tend to be smaller for light sources with high colour fidelity values, and they are affected by spectral characteristics of different lighting technologies. The magnitude of variation in colour rendition measures, up to 5–10 units in IES TM-30-15 (Rf, Rg), measures is compared with other sources of variability and ambiguity.
关键词： IES TM-30-15,inter-observer variation,colour rendition,light sources,colorimetry
更新于2025-09-23 15:23:52
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Dual-mode Au nanoprobe based on surface enhancement Raman scattering and colorimetry for sensitive determination of telomerase activity both in cell extracts and the urine of patients
摘要： Telomerase is a valuable biomarker, which is highly correlated to cancer diseases. However, single-mode probe for telomerase detection cannot satisfy the challenge of detection of telomerase activity rapidly, simply with high selectivity, sensitivity and accuracy both in preliminary diagnosis and point of care (POC) testing. Therefore, there is an urgent need to develop a robust approach with controllable assembly and high accuracy to consider both the simplification of preliminary diagnosis and POC testing and the quantification requirement for early clinical diagnosis and treatment. Herein, a novel dual-mode Au NPs probe was developed for determination of telomerase activity with controllable assembly and aggregation statement based on surface enhancement Raman scattering (SERS) and colorimetry. In this strategy, an Au dimer-based probe with high uniformity was assembled successfully, telomerase activity was reflected according to the color variations of solution and the Raman intensity of Raman reporter. Taking advantage of the uniformity of Au dimers and the combination of colorimetry and SERS techniques, our strategy determined the telomerase activity with high accuracy, sensitivity and wide range. The established probe possessed of high selectivity, sensitivity and accuracy, which was approved as a reliable, intuitional and convenient approach for detecting telomerase activity.
关键词： colorimetry,bladder cancer,surface enhanced Raman scattering,Au nanoparticles,telomerase activity
更新于2025-09-23 15:21:21
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[IEEE 2018 VII. Lighting Conference of the Visegrad Countries (Lumen V4) - Trebic, Czech Republic (2018.9.18-2018.9.20)] 2018 VII. Lighting Conference of the Visegrad Countries (Lumen V4) - Color Rendition of Artificial Light Sources: Past and Future
摘要： During last decade it is visible new impulse in case of color quality evaluation of artificial light sources. New ideas are based on criticism of CIE color rendering index Ra that appears insufficient especially for solid state light sources, nevertheless proposed metrics aren’t broadly accepted. In this article is presented short overview of color rendering indices history with discussion about possible improvement of CIE color rendering index by gamut mapping.
关键词： color,TM 30-15,colorimetry,light source,color rendering index
更新于2025-09-23 15:21:21
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[IEEE 2018 VII. Lighting Conference of the Visegrad Countries (Lumen V4) - Trebic, Czech Republic (2018.9.18-2018.9.20)] 2018 VII. Lighting Conference of the Visegrad Countries (Lumen V4) - Colorimetric Characterization of Modern Mobile Displays
摘要： Due to the development of display technology higher and higher resolution devices are getting on the market. To characterize those high resolution display devices special measurement techniques are needed partly because most of them are handheld devices. Based on the recommendation of the International Committee for Display Metrology we have characterized some modern mobile displays and investigated how to choose the right application area of those devices. We have also tested if those devices would be proper to use them as diagnostic medical devices used by medical doctors.
关键词： AMOLED,colorimetry,mobile display,LED,photometry
更新于2025-09-23 15:21:21
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Carbon quantum dots originated from chicken blood as peroxidase mimics for colorimetric detection of biothiols
摘要： Carbon quantum dots (CQDs) were prepared from chicken blood by hydrothermal method, which could catalyze the oxidation of 3, 3′, 5, 5′-tetramethylbenzidine (TMB) in the presence of H2O2 to generate the blue oxidized TMB (ox-TMB) with a strong absorption peak at 652 nm. However, the introduction of biothiols could induce the reduction of ox-TMB, leading to shallower blueness and lower absorbance. Based on this fact, a convenient and sensitive colorimetric method for detection of biothiols using CQDs as peroxidase mimics was established. Several factors, such as acidity, temperature, incubating time, CQDs dosage, H2O2 and TMB concentrations, which might influence the response of the analysis signal, were optimized by taking cysteine (CySH) as an example. Under the selected conditions, sensitive detection of biothiols was achieved, and the limits of detection (LOD) for CySH, glutathione (GSH), and homocysteine (HcySH) were 0.4, 0.6, and 0.9 μM respectively. This method was successfully applied for the determination of CySH in human serum samples with the recovery of 91.5%–109.3%, indicating the potential application of this method for biothiols sensing in real samples.
关键词： Determination,Carbon quantum dots,Peroxidase mimics,Colorimetry
更新于2025-09-23 15:21:01
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Silver and gold nanoparticles as multi-chromatic lateral flow assay probes for the detection of food allergens
摘要： In this study, we report the simultaneous use of gold and silver nanoparticles to set a multicolor multiplex lateral flow immunoassay (xLFIA). Silver nanoparticles (AgNPs), spherical in shape and characterized by a brilliant yellow color, were obtained by a new viable one-step synthetic protocol. AgNPs were stable over time and acceptably robust to conditions used for fabricating LFIA devices. These AgNPs were employed as a colorimetric probe in combination with two different kinds of gold nanoparticles (AuNPs) to set a visual xLFIA for detecting allergens. Surface plasmon resonance peaks of probes (AgNPs, spherical and desert rose-like AuNPs) were centered at 420, 525, and 620 nm, respectively. Therefore, the xLFIA output was easily interpreted through a Byellow magenta cyan (YMC)^ color code. The prospect of the YMC xLFIA was demonstrated by simultaneously detecting three major allergens in bakery products. Antibodies directed towards casein, ovalbumin, and hazelnut allergenic proteins were individually adsorbed onto metal nanoparticles to produce three differently colored specific probes. These were inserted in a LFIA comprising three lines, each responsive for one allergen. The trichromatic xLFIA was able to detect allergenic proteins at levels as low as 0.1 mg/l and enabled the easy identification of the allergens in commercial biscuits based on the color of the probes.
关键词： Multiplex detection,Hazelnut,Ovalbumin,Colorimetry,Immunochromatographic strip test,Casein
更新于2025-09-23 15:21:01