Abstract:Based on blue LED chips to excite Ce-doped yttrium aluminum garnet (YAG: Ce 3+) yellow phosphors, InP/ZnS green-emitting quantum dots (QDs) and InP/ZnSe/ZnS red-emitting QDs are used as light conversion materials for WLEDs to improve the color rendering index (CRI) of the device and improve its color coordinates. We have proven this in previous work. But in the previous work, we only studied the CRI of the driving current from 5 mA to 100 mA. The CRI and the Commission International de L'Eclairage (CIE) chroma… Show more
“…The process of luminescent layer production was directed so that after the optimisation of the luminescent layer parameters, the generated light would fall within this narrowly defined region and in the vicinity of Illuminant E, which is the point of spectral equilibrium in the CIE 1931 colour diagram. Indeed, light with a location in the vicinity of Illuminant E is known to have CCT values corresponding to daylight white light and high CRI values [8], [9], [32], [33]. These are therefore desirable colorimetric parameters suitable even for demanding lighting applications.…”
Section: Measurement Of Colorimetric Parametersmentioning
confidence: 99%
“…At the same time, according to this standard, a CCT in the range 4000-6500 K is required for several types of workplaces. In doing so, it is known that within the CIE 1931 colour chart, light with the required CRI and CCT values is in the vicinity of Illuminant E [8], [9], [32], [33]. Therefore, the optimization process for the production of luminescence samples was conducted in such a way that the CIEx,y 1931 color coordinates of the light generated by the luminescence layers were as close to Illuminant E as possible.…”
Section: A Measurements For Optimisation Of Luminescent Layers With R...mentioning
confidence: 99%
“…For example, the authors of [8] used red light-emitting carbon dots (R-CDs), combining a blue chip, a YAG:Ce phosphor and R-CDs to create a WLED with a CRI = 90.9 at colour coordinates CIE x,y = (0.344; 0.333). The use of InP/ZnS Green-Emitting and InP/ZnSe/ZnS Red-Emitting Quantum Dots in combination with a blue chip and a YAG:Ce phosphor is presented in [9], and the WLED prepared in this way exhibited CRI = 91 and CCT = 5313 K for colour coordinates (0.3365; 0.3334).…”
This publication describes the measurement of the effect of selected luminescent layer parameters on the light and communication characteristics of light generated by a luminescent layer using a light emitting diode (LED) as a radiation source. The luminescent layers were implemented based on a combination of polydimethylsiloxane (PDMS) polymer and YAG:Ce and CaS:Eu phosphors by spin coating. For the chosen weight ratios of PDMS and phosphors, a set of test samples of luminescent layers was implemented whose thicknesses differed from each other in the order of units to tens of micrometres. Experimental measurements have clearly shown that even a slightest change in the thickness of the luminescent layer has a non-negligible effect on the change of the luminous and communication parameters of the light generated by the luminescent layer. The colorimetric parameters of the colour colorimetry temperature (CCT), colour rendering index (CRI) and colour coordinates x, y (CIE 1931) were recorded for the investigated luminescent samples. The communication parameters were evaluated by measuring the error vector magnitude (EVM), modulation error ratio (MER), phase error, bit error rate (BER) and normalised signal-to-noise ratio E b /N0.
“…The process of luminescent layer production was directed so that after the optimisation of the luminescent layer parameters, the generated light would fall within this narrowly defined region and in the vicinity of Illuminant E, which is the point of spectral equilibrium in the CIE 1931 colour diagram. Indeed, light with a location in the vicinity of Illuminant E is known to have CCT values corresponding to daylight white light and high CRI values [8], [9], [32], [33]. These are therefore desirable colorimetric parameters suitable even for demanding lighting applications.…”
Section: Measurement Of Colorimetric Parametersmentioning
confidence: 99%
“…At the same time, according to this standard, a CCT in the range 4000-6500 K is required for several types of workplaces. In doing so, it is known that within the CIE 1931 colour chart, light with the required CRI and CCT values is in the vicinity of Illuminant E [8], [9], [32], [33]. Therefore, the optimization process for the production of luminescence samples was conducted in such a way that the CIEx,y 1931 color coordinates of the light generated by the luminescence layers were as close to Illuminant E as possible.…”
Section: A Measurements For Optimisation Of Luminescent Layers With R...mentioning
confidence: 99%
“…For example, the authors of [8] used red light-emitting carbon dots (R-CDs), combining a blue chip, a YAG:Ce phosphor and R-CDs to create a WLED with a CRI = 90.9 at colour coordinates CIE x,y = (0.344; 0.333). The use of InP/ZnS Green-Emitting and InP/ZnSe/ZnS Red-Emitting Quantum Dots in combination with a blue chip and a YAG:Ce phosphor is presented in [9], and the WLED prepared in this way exhibited CRI = 91 and CCT = 5313 K for colour coordinates (0.3365; 0.3334).…”
This publication describes the measurement of the effect of selected luminescent layer parameters on the light and communication characteristics of light generated by a luminescent layer using a light emitting diode (LED) as a radiation source. The luminescent layers were implemented based on a combination of polydimethylsiloxane (PDMS) polymer and YAG:Ce and CaS:Eu phosphors by spin coating. For the chosen weight ratios of PDMS and phosphors, a set of test samples of luminescent layers was implemented whose thicknesses differed from each other in the order of units to tens of micrometres. Experimental measurements have clearly shown that even a slightest change in the thickness of the luminescent layer has a non-negligible effect on the change of the luminous and communication parameters of the light generated by the luminescent layer. The colorimetric parameters of the colour colorimetry temperature (CCT), colour rendering index (CRI) and colour coordinates x, y (CIE 1931) were recorded for the investigated luminescent samples. The communication parameters were evaluated by measuring the error vector magnitude (EVM), modulation error ratio (MER), phase error, bit error rate (BER) and normalised signal-to-noise ratio E b /N0.
“…In recent years, quantum dots (QDs) have attracted wide attention due to their adjustable wavelength, high color purity, and quantum efficiency, which have been successfully applied in display fields 1–3 . At present, researches on QDs for display applications mainly include two aspects: electroluminescence (EL) technology 4–6 and photoluminescence (PL) technology 7–9 .…”
Section: Introductionmentioning
confidence: 99%
“…In recent years, quantum dots (QDs) have attracted wide attention due to their adjustable wavelength, high color purity, and quantum efficiency, which have been successfully applied in display fields. [1][2][3] At present, researches on QDs for display applications mainly include two aspects: electroluminescence (EL) technology [4][5][6] and photoluminescence (PL) technology. [7][8][9] Combining QDs luminescent materials with matrix materials to form new composite luminescent materials has been the focus of researchers in the scientific and industrial communities, and it is also the key to the application of QDs in liquid crystal display backlights.…”
Quantum dots (QDs) are one kind of photoluminescent materials with excellent properties, such as adjustable spectrum, narrow full width at half maximum (FWHM), and high color gamut. In this paper, a photoluminescent QDs printing paste suitable for light guide dots array applied in the backlight for liquid crystal display (LCD) was presented. The QDs printing paste was first prepared and characterized with different kinds of solvents. Then, triphenyl phosphite (TPP), a kind of antioxygen, was added into the QDs printing paste to improve the stability of the QDs printing paste. Finally, a QDs light guide plate (LGP) was fabricated by screen printing with QDs printing paste added with silicon dioxide (SiO 2 ) light scattering particles. The color gamut of QDsLGP arrived 131.6%NTSC due to light scattering interaction between blue LED, red QDs, green QDs, and SiO 2 particles. The results showed that the QDs-chloroform printing paste had uniform light output and the highest photoluminescent peak intensity. Therefore, the composite screen printing paste has wide application prospects in the backlight of LCD, with the advantages of simple process, high production efficiency, and low cost.
Energy‐efficient white light‐emitting diodes (LEDs) are in high demand across the society. Despite the significant advancements in the modern lighting industry based on solid‐state electronics and inorganic phosphor, solid‐state lighting (SSL) continues to pursue improved efficiency, saturated color performance, and longer lifetime. Here in this article, robust, narrow emission band nanorods (NRs) are disclosed with tailored wavelengths, aiming to enhance the color rendering index (CRI) and luminous efficacy (LE). The fabricated lighting device consists of NRs of configuration CdSe/ZnxCd1‐xS/ZnS, which can independently tune CRI R1‐R9 values and maximize the luminous efficacy. For general lighting, NRs with quantum yield (QY) up to 96% and 99% are developed, resulting in ultra‐efficient LEDs reaching a record high luminous efficacy of 214 lm W−1 (certified by the National Accreditation Service). Furthermore, NRs are deployed onto mid‐power (0.3 W@ 50 mA) LEDs, showing significantly enhanced long‐term stability (T95 = 400 h @ 50 mA). With these astonishing properties, the proposed NRs can pave the way for efficient lighting with desired optical spectrum.
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