Ultraviolet to blue blocking and wavelength convertible films using carbon dots for interrupting eye damage caused by general lighting

Due to the excellent characteristics of energy‐saving, environmentally friendly and long‐life, the solid‐state lighting based on white light‐emitting diodes (WLEDs) is an emerging technology to replace traditional lighting solutions. However, the lack of red component of the most established method for fabricating commercial WLEDs results in high correlated color temperature (CCT) and low color rendering index (CRI). Herein, red‐emitting carbon dots (R‐CDs) with self‐quenching‐resistant property are synthesized using melamine and dithiosalicylic acid as precursors. In addition, R‐CDs exhibit high thermal and photostability under high temperature and strong blue light irradiation. On the basis of the unique features of R‐CDs, a WLED is fabricated by combining a blue‐LED chip with commercial Ce3+:Y3Al5O12 and R‐CDs phosphors, which exhibits warm white light with a color coordinate of (0.41, 0.38), a high CRI of 92.7 and a CCT of 3827 K. Besides, the WLED exhibits good optical stability upon the increase of drive current from 20 to 100 mA. The results suggest R‐CDs can be used as a color converter to fabricate high‐quality warm WLEDs.

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“…Therefore, increasing the amount of R‐CDs can reduce the blue light emission of WLEDs, making it more eyes‐protecting. [ 52 ]…”

Section: Resultsmentioning

confidence: 99%

Self‐Quenching‐Resistant Red Emissive Carbon Dots with High Stability for Warm White Light‐Emitting Diodes with a High Color Rendering Index

Zhang

Yang

Wan

et al. 2020

Advanced Optical Materials

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“…[4,5] However,such design has adrawback:the emission of blue light originating from the blue chip is much more intense than the one of yellow light originating from phosphors. [6,7] Artificial blue-rich white light has been reported to have negative effects on sleep-wake cycles,eating patterns,m etabolism, and mental alertness,a st he photo-sensitive ganglion cells in the retina signal the brain to stop producing melatonin. [8][9][10] Hence,t he blue-light emission for LED lighting technology is becoming an important concern for public health.…”

Section: Introductionmentioning

confidence: 99%

Doped Lead Halide White Phosphors for Very High Efficiency and Ultra‐High Color Rendering

et al. 2020

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Near-UV-pumped white-light-emitting diodes with ultra-high color rendering and decreased blue-light emission is highly desirable.H owever,d iscovering as ingle-phase white light emitter with such characteristics remains challenging. Herein, we demonstrate that Mn doping as lowa s0 .027 %i n the hybrid post-perovskite type (TDMP)PbBr 4 (TDMP = trans-2,5-dimethylpiperaziniium) enables to achieve ab right pure white emission replicating the spectrum of the sunsrays. Thus,awhite phosphor exhibiting an emission with CIE coordinates (0.330, 0.365), ahigh photoluminescence quantum yield of 60 %( new recordf or white light emission of hybrid lead halides), and an ultra-high color rendering index (CRI = 96, R9 = 91.8), corresponding to the recordv alue for as ingle phase emitter was obtained. The investigation of the photoluminescence properties revealed how free excitons,s elftrapped excitons,and lowamount of Mn dopants are coupled to give rise to such pure white emission.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

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“…Nowadays, a blue chip (InGaN) coated with yellow phosphors (YAG: Ce 3+ ) is widely used to produce the commercial wLEDs . However, such design has a drawback: the emission of blue light originating from the blue chip is much more intense than the one of yellow light originating from phosphors . Artificial blue‐rich white light has been reported to have negative effects on sleep–wake cycles, eating patterns, metabolism, and mental alertness, as the photosensitive ganglion cells in the retina signal the brain to stop producing melatonin .…”

Section: Introductionmentioning

confidence: 99%

Doped Lead Halide White Phosphors for Very High Efficiency and Ultra‐High Color Rendering

et al. 2020

View full text Add to dashboard Cite

Near‐UV‐pumped white‐light‐emitting diodes with ultra‐high color rendering and decreased blue‐light emission is highly desirable. However, discovering a single‐phase white light emitter with such characteristics remains challenging. Herein, we demonstrate that Mn doping as low as 0.027 % in the hybrid post‐perovskite type (TDMP)PbBr4 (TDMP=trans‐2,5‐dimethylpiperaziniium) enables to achieve a bright pure white emission replicating the spectrum of the sun's rays. Thus, a white phosphor exhibiting an emission with CIE coordinates (0.330, 0.365), a high photoluminescence quantum yield of 60 % (new record for white light emission of hybrid lead halides), and an ultra‐high color rendering index (CRI=96, R9=91.8), corresponding to the record value for a single phase emitter was obtained. The investigation of the photoluminescence properties revealed how free excitons, self‐trapped excitons, and low amount of Mn dopants are coupled to give rise to such pure white emission.

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Ultraviolet to blue blocking and wavelength convertible films using carbon dots for interrupting eye damage caused by general lighting

Cited by 86 publications

References 40 publications

Self‐Quenching‐Resistant Red Emissive Carbon Dots with High Stability for Warm White Light‐Emitting Diodes with a High Color Rendering Index

Self‐Quenching‐Resistant Red Emissive Carbon Dots with High Stability for Warm White Light‐Emitting Diodes with a High Color Rendering Index

Doped Lead Halide White Phosphors for Very High Efficiency and Ultra‐High Color Rendering

Doped Lead Halide White Phosphors for Very High Efficiency and Ultra‐High Color Rendering

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