High power laser-driven ceramic phosphor plate for outstanding efficient white light conversion in application of automotive lighting

Song, Young Hoon; Ji, Eun Kyung; Jeong, Byung Woo; Jung, Mong Kwon; Kim, Eun Young; Yoon, Dae Ho

doi:10.1038/srep31206

Cited by 94 publications

(32 citation statements)

References 26 publications

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“…Obtaining stable colloidal solutions is a strong advantage of this technique with respect to the others, as it produces individual YAG nanocrystals that can be (1) used as nanoprobes for any further development in biology and (2) shaped as nanostructured lms 20,21 or as scattering-control nanoceramics to obtain enhanced light extraction in solidstate lighting devices. 22 In the literature, most reported solvothermal syntheses use commercial autoclaves operating at a maximal temperature of 300 C with an autogenous pressure, which builds up as the precursor and solvent decomposition happens. Consequently, the reaction occurs under a non-stationary state (pressure increasing up to 60-70 bar upon reaction time) that is detrimental for the nucleation and growth control.…”

Section: Introductionmentioning

confidence: 99%

A new solvothermal method for the synthesis of size-controlled YAG:Ce single-nanocrystals

et al. 2018

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Ce 3+ -doped Y 3 Al 5 O 12 (YAG:Ce) nanocrystals were synthesized by a unique solvothermal method, under sub-critical conditions. A home-made autoclave was used, operating in a larger pressure and temperature range than that with conventional commercial equipment and allowing direct in situ photoluminescence (PL) and X-ray absorption characterizations. The study of various synthesis conditions (pressure, temperature, precursor concentration, reaction time) allowed the best reaction conditions to be pinpointed to control YAG:Ce nanocrystal size, as well as crystal quality, and to get efficient optical properties. Without any post thermal treatment, we succeeded in obtaining wellcrystallized YAG:Ce nanocrystals (30-200 nm), displaying typical PL properties of YAG:Ce with a maximal emission at 550 nm. The pristine 100 nm-sized YAG:Ce nanoparticles present an internal quantum yield of about 40 AE 5%. In situ X-ray absorption near edge spectroscopy demonstrates the presence of Ce 4+ in nanocrystals elaborated at high temperature, resulting from the oxidation of Ce 3+ during the crystallization process. † Electronic supplementary information (ESI) available: Additional TEM images and nanocrystal size distribution histograms (.pdf le). A movie for the in situ visualization upon YAG nanocrystal synthesis (.mpeg le). SeeFig. 3 TEM images of YAG:Ce nanocrystals synthesized at different pressure with T ¼ 350 C, [Al] ¼ 0.09 mol L À1 and reaction time ¼ 150 min. Some individual nanocrystals are circled with yellow solid lines. An aggregate is circled with a white dashed line.This journal is

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Section: Introductionmentioning

confidence: 99%

A new solvothermal method for the synthesis of size-controlled YAG:Ce single-nanocrystals

et al. 2018

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“…Both these loss mechanisms scale with temperature 10 (e.g., as a result of illumination) and therefore phosphor luminescence suffers from saturation 10 , aging 11 , and thermal quenching 10 , limiting the irradiance tõ 5 kW cm −2 and thus the overall light output. Even though new concepts such as glass encapsulation 12,13 , phosphor monoliths 14 , or composite ceramic phosphors [15][16][17] can increase the irradiance level up to~10-20 kW cm −2 , the true potential of lasers for highbrightness lighting applications, with possible light outputs of several MW cm −2 , still remains unemployed.…”

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confidence: 99%

Conversionless efficient and broadband laser light diffusers for high brightness illumination applications

et al. 2020

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Laser diodes are efficient light sources. However, state-of-the-art laser diode-based lighting systems rely on light-converting inorganic phosphor materials, which strongly limit the efficiency and lifetime, as well as achievable light output due to energy losses, saturation, thermal degradation, and low irradiance levels. Here, we demonstrate a macroscopically expanded, three-dimensional diffuser composed of interconnected hollow hexagonal boron nitride microtubes with nanoscopic wall-thickness, acting as an artificial solid fog, capable of withstanding~10 times the irradiance level of remote phosphors. In contrast to phosphors, no light conversion is required as the diffuser relies solely on strong broadband (full visible range) lossless multiple light scattering events, enabled by a highly porous (>99.99%) nonabsorbing nanoarchitecture, resulting in efficiencies of~98%. This can unleash the potential of lasers for high-brightness lighting applications, such as automotive headlights, projection technology or lighting for large spaces.

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“…In addition, the intense research into oxyfluorides phosphor, to the best of our knowledge, the oxyfluoride ceramic phosphor plate has not been studied as a phosphor converter in solid‐state lighting. Ceramic and glass ceramic phosphors have been proposed as a good candidate to replace silicon or epoxy resin in high power LEDs and laser lighting technology . They offer advantages such as uniform illumination, and excellent thermal and mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Dual color tuning in Ce³⁺‐doped oxyfluoride ceramic phosphor plate for white LED application

et al. 2018

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Ceramic phosphor plates of cerium (Ce3+)‐doped oxyfluoride were fabricated by the solid‐state reaction method. These phosphors exhibit efficient emission, with the novel feature of color tuning by varying both the doping concentration and excitation wavelength. As the Ce3+ concentration increases, the excitation spectrum broadens by a factor of 1.6, and the excitation peak wavelength shifts from 390 to 435 nm, and there is a variation in excitation energy of ~ 10%. Luminescence spectrum of low Ce3+ concentration samples is tuned from blue to green with the change of excitation wavelength. The emission peak exhibits a shift of 58 nm into the red spectral region, varying the Ce3+ concentration from 0.05 to 0.1 mol%; whereas this shift is only 6 nm when Ce3+ content changes from 0.25 to 1 mol%. Photoluminescence (PL) quantum yield has achieved 76%. The crystal structure was examined using X‐ray diffraction to explain its possible influence on the redshift luminescence. A proof of concept of white LED was constructed using a 450 nm blue LED chip with an oxyfluoride phosphor plate, showing a luminous efficacy (LE) of 64 lm/W with a color rendering index of 74.

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High power laser-driven ceramic phosphor plate for outstanding efficient white light conversion in application of automotive lighting

Cited by 94 publications

References 26 publications

A new solvothermal method for the synthesis of size-controlled YAG:Ce single-nanocrystals

A new solvothermal method for the synthesis of size-controlled YAG:Ce single-nanocrystals

Conversionless efficient and broadband laser light diffusers for high brightness illumination applications

Dual color tuning in Ce³⁺‐doped oxyfluoride ceramic phosphor plate for white LED application

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High power laser-driven ceramic phosphor plate for outstanding efficient white light conversion in application of automotive lighting

Cited by 94 publications

References 26 publications

A new solvothermal method for the synthesis of size-controlled YAG:Ce single-nanocrystals

A new solvothermal method for the synthesis of size-controlled YAG:Ce single-nanocrystals

Conversionless efficient and broadband laser light diffusers for high brightness illumination applications

Dual color tuning in Ce3+‐doped oxyfluoride ceramic phosphor plate for white LED application

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Dual color tuning in Ce³⁺‐doped oxyfluoride ceramic phosphor plate for white LED application