Improvement of color-rendering characteristics of white light emitting diodes by using red quantum dot films

Hong, Sung-Hwa; Gwak, Sunjae; Park, S.; Lee, G.J.; Lee, J.-G.; Ko, Jae‐Hyeon; Joe, Seuk-Jin; Kim, Y.; Park, T.; Ko, Young-Jo

doi:10.1016/j.cap.2021.09.008

Cited by 10 publications

(15 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This indicates that the diffuser plate mixes the light enough to remove any possible difference in the optical path length depending on the viewing angle via the red QD cap. This result contrasts with the case where red QD films are adopted on the diffuser plate in the direct-lit white LED lighting [ 39 ]. When the QD film is on the diffuser plate, the optical path length in the film depends on the propagation angle of the excitation light, resulting in significantly higher color conversion at larger viewing angles.…”

Section: Resultsmentioning

confidence: 71%

“…In addition to the homogeneous dispersion, silica is known to be stable against moisture and air, which enhances the long-term stability of QDs. The details of the preparation of QD particles were described elsewhere [ 39 ].…”

Section: Methodsmentioning

confidence: 99%

“…Successful fabrication of large-size QD films accelerated their applications in display backlights and general lighting. However, the optical path length difference in the QD component sometimes causes color dispersion problems displaying different color properties depending on the viewing angle [ 39 ].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Substantial Improvement of Color-Rendering Properties of Conventional White LEDs Using Remote-Type Red Quantum-Dot Caps

et al. 2022

View full text Add to dashboard Cite

A new type of remote red quantum-dot (QD) component was designed and fabricated to improve the color-rendering properties of conventional white LED (light-emitting diode) lightings. Based on an optical simulation, the rectangular cavity-type QD cap was designed with an opening window on the top surface. Red QD caps were fabricated using a typical injection molding technique and CdSe/ZnS QDs with a core/shell structure whose average size was ~6 nm. Red QD caps were applied to conventional 6-inch, 15-W white LED downlighting consisting of 72 LEDs arrayed concentrically. The red QD caps placed over white LEDs enhanced the red components in the long-wavelength range resulting in the increase of the color rendering index (CRI) from 82.9 to 94.5. The correlated color temperature was tuned easily in a wide range by adopting various configurations consisting of different QD caps. The spatial and angular homogeneities were secured on the emitting area because QD caps placed over the white LEDs did not exhibit any substantial optical path length difference. The present study demonstrates that adopting QD caps in conventional LED lightings provides a flexible and efficient method to realize a high color-rendering property and to adjust correlated color temperature appropriately for a specific application.

show abstract

Section: Resultsmentioning

confidence: 71%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Substantial Improvement of Color-Rendering Properties of Conventional White LEDs Using Remote-Type Red Quantum-Dot Caps

et al. 2022

View full text Add to dashboard Cite

show abstract

“…For example, QD particles were incorporated in polymers or glasses as composites in various forms [34][35][36][37][38][39][40][41][42][43][44][45][46][47]. In addition, large-size QD films or QD caps could be developed for practical applications in displays and illumination [48][49][50]. These designs could improve the efficiency, colorrendering characteristics, and long-term stability of W-LEDs successfully.…”

Section: Introductionmentioning

confidence: 99%

Structural Optimization of Vertically-Stacked White LEDs with a Yellow Phosphor Plate and a Red Quantum-Dot Film

Hong

2022

Nanomaterials

View full text Add to dashboard Cite

A remote-type white light-emitting diode (LED) consisting of a red quantum-dot (QD) film and a yellow phosphor plate was studied by both experiment and optical simulation. The sequence of the two color-conversion films had a substantial effect on the color-rendering properties of the vertically-stacked white LED, and the optimized configuration exhibited a high color rendering index of more than 90 thanks to the enhanced red component via the QD film. For the design of high-power white LED devices of a remote type, it was necessary to locate the color-conversion films below the diffuser plate to remove the substantial color dispersion depending on the viewing angle. The present study shows that high power and high color-rendering white LED devices can be realized in terms of two vertically-stacked color-conversion materials, which would provide long-term stability due to the remote design.

show abstract

“…[7][8][9][10][11][12] LED is a semiconductor light source that has attracted scientists due to its superior advantages as energy-efficient, 13 less heat, high brightness, 14 and lower cost compared to conventional light sources such as incandescent and fluorescent lamps. [15][16][17][18] To obtain accurate measurements for these sources, the uncertainty budget must be calculated. The uncertainty budget for flux is estimated by several elements, such as self-absorption, mismatch factor, uncertainty due to the reference standard lamps, and linearity of the photodetector.…”

mentioning

confidence: 99%

Uncertainty Estimation of Luminous Flux for LED Lamps Due to the Control of Electric Power

El-Moghazy¹,

Gaballah²

2022

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

Electrical power efficiency has been of interest to both energy providers and consumers as it plays a pivotal role in our daily life. The voltage fluctuation is a significant issue with power quality since it has a substantial influence on electronic devices in addition to its economic impact. Several contributions have been dedicated to estimating the uncertainty in luminous flux including various parameters; however, most of them have been focused on traditional light sources such as incandescent lamps. One of the main parameters that have not been considered is the uncertainty in electric power due to voltage instabilities. In this study, the effect of regulating the electric power on the luminous flux and its combined uncertainty for different brands of LED lamps were explored. The LED lamps currently available in the Egyptian market have been tested according to their photometric and electric parameters. Three different brands labeled E, T, and V have been chosen with nominal power of 9 and 15 Watt. The experimental testing of such lamps showed that the power factors have a considerable effect on the combined uncertainty of the overall luminous flux.

show abstract

Improvement of color-rendering characteristics of white light emitting diodes by using red quantum dot films

Cited by 10 publications

References 21 publications

Substantial Improvement of Color-Rendering Properties of Conventional White LEDs Using Remote-Type Red Quantum-Dot Caps

Substantial Improvement of Color-Rendering Properties of Conventional White LEDs Using Remote-Type Red Quantum-Dot Caps

Structural Optimization of Vertically-Stacked White LEDs with a Yellow Phosphor Plate and a Red Quantum-Dot Film

Uncertainty Estimation of Luminous Flux for LED Lamps Due to the Control of Electric Power

Contact Info

Product

Resources

About