Warm White Light with a High Color-Rendering Index from a Single Gd₃Al₄GaO₁₂:Ce³⁺ Transparent Ceramic for High-Power LEDs and LDs

Abstract

Transparent ceramics (TCs) are promising for high-power (hp) white light-emitting diode (WLED) and laser diode (LD) lighting. However, comfortable warm white light has not been achieved only using a single TC in hp-WLEDs/ LDs. Herein, highly transparent Gd 3 Al 4 GaO 12 :Ce 3+ (GAGG:Ce 3+ ) TCs (transmittance, T = 55.9−80.2%) were prepared via a solid-state reaction. Ce 3+ as a doped activator center in grains plays a positive role in luminescence based on the microstructural investigations by scanning electron microscopy and the cathodoluminescence system. T decreases upon increasing the Ce 3+ concentration and/or the ceramic thickness, whereas the luminous efficacy of hp-WLEDs/LDs goes up. For blue hp-LEDs driven at 350 mA or LDs of 2 W, warm white light with a low correlated-color temperature of ∼3000 K was achieved by a single GAGG:Ce 3+ TC, benefiting from its broad emission band (full width at half maximum, FWHM = 133−137 nm) and abundant red components (peaking at about 568−574 nm). The color-rendering index of hp-WLEDs reaches 78.9. These results are much better than the performance of the traditional Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce 3+ ) TC, indicating that GAGG:Ce 3+ TCs are promising color converters for hp-WLEDs/LDs with a comfortable warm white light. KEYWORDS: Gd 3 Al 4 GaO 12 :Ce 3+ , transparent ceramic, high-power white LEDs, laser-driven lighting, warm white light

Enhancing photoluminescence properties of Mn4+‐activated Sr4−xBaxAl14O25 red phosphors for plant cultivation LEDs

“…According to previous reports, the AlO 6 octahedral is suited to the Mn 4+ activator deposit that exhibit strong red emission. 26 For instance, the phenomenon also be found in these phosphors of Ca 14 phosphors. Comprehensively presented above, the Mn 4+ -activated aluminate phosphors are developed because of their excellent properties of environmental friendliness, simple preparation process, low price, and good stability.…”

“…Generally speaking, the demand of plant is divided into blue light (400‐500 nm), red light (600‐690 nm), and far‐red light (700‐740 nm) that corresponding to the photosynthesis, phototropism, and photomorphogenesis of plant, respectively. Therefore, the red and far‐red light regions play a crucial role in the physiological cycle . Therefore, in order to meet the needs of plants for light energy, it is very significance to prepare a kind of high‐performance phosphor that can be strongly absorbed in blue region and emitted in red light for plant cultivation.…”

“…Therefore, the red and far-red light regions play a crucial role in the physiological cycle. [12][13][14] Therefore, in order to meet the needs of plants for light energy, it is very significance to prepare a kind of high-performance phosphor that can be strongly absorbed in blue region and emitted in red light for plant cultivation.…”

Unique Design Strategy for Laser‐Driven Color Converters Enabling Superhigh‐Luminance and High‐Directionality White Light

“…We can see that the collected optical power of HSYAG2 is 22.3% higher than that of MSYAG and the color rendering index (CRI) is also improved from 56 to 65. Though the red content of HSYAG2 (≈6%) as specified by ECE R113 can meet the demand for vehicle lighting (≥5%), the CRI of HSYAG2 is still low for general lighting and can be enhanced by spectral design or adding red phosphor component …”

Energy transfer induced white‐light‐emitting phosphor by co‐doping Ce3+, Tb3+ and Mn2+ into the single Ba9Lu2Si6O24 host

“…Solid‐state lighting devices based on white light‐emitting‐diodes (WLEDs) are considered to be promising for facilitating the development of society, due to their virtues of energy‐saving, environmental friendliness, long service lifetime, and high efficiency . Commonly, WLEDs are fabricated by the combination of a yellow‐emitting YAG:Ce 3+ phosphor and a blue InGaN chip .…”