Facile synthesis and optical properties of Ce:YAG polycrystalline ceramics with different SiO₂content

Abstract

According to the FESEM micrographs of the as-prepared samples, they show the texture of polycrystalline materials and better uniformity appears in sample A.

High recorded color rendering index in single Ce,(Pr,Mn):YAG transparent ceramics for high-power white LEDs/LDs

“…S1 (ESI †). Moreover, it has been pointed out that the second phases and micro-pores can act as scattering centers in phosphor ceramics, 6,11,45,[54][55][56][57][58] resulting in increased extraction efficiency of the incident blue light, which has a favorable effect on the luminous performance of TCs. Actually, in the application of white LED lighting, the second phase indeed enhances the utilization of incident blue light and weakens the TIR (total interface refraction).…”

“…Unfortunately, with the rising power of white LEDs and LDs, this phosphor usually suffers from decreasing luminous efficiency and chromaticity shifts due to heat accumulation. Therefore, color converters such as glass ceramics or phosphors in glass (PiG), [4][5][6][7] single crystals (SCs), [8][9][10] and transparent ceramics (TCs) [11][12][13] have been proposed to replace the applied phosphor due to their facile implementation of the remote encapsulation mode. Compared with PiG and SCs, Ce:YAG TCs are developing rapidly due to their low cost, ease of achieving high doping concentration, short production cycles, high thermal conductivity (about 14 W m À1 K À1 ) and high mechanical strength.…”

Absorption and Remission Characterization of Pure, Dielectric (Nano-)Powders Using Diffuse Reflectance Spectroscopy: An End-To-End Instruction

“…In contrast to TiO 2 , YAG:Ce possesses a vastly different diffuse reflectance spectrum. The Ce 3+ absorption band at approximately 460 nm induced by its 2 F 5/2 → 5d 1 electronic transition [88,89] dominates the otherwise high diffuse reflectance which rivals that of the used white standard above 550 nm. Even in the center of this absorption band, the diffuse reflectance does not fall below ≈0.1, once again underlying the material-specific interplay between absorption and scattering.…”

“…Even in the center of this absorption band, the diffuse reflectance does not fall below ≈0.1, once again underlying the material-specific interplay between absorption and scattering. A second absorption dip of the diffuse reflectance in the UV below 370 nm indicates the onset of the 2 F 5/2 → 5d 2 transition of Ce 3+ [88,89].…”

“…Alternatively, the forward scan direction (shorter to longer wavelengths) can be used if the investigated spectral range is divided into distinct sections: First, the region is investigated where no luminescence is present; the diffuse reflectance at regions of high absorption that are the prerequisite for luminescence are to be assessed lastly. However, wavelength regions with overlapping emission and absorption bands [89,102] may pose a hindrance and need to be evaluated on a case by case basis. Nevertheless, the use of color filters is recommended in either circumstance.…”