Glass‐Crystallized Luminescence Translucent Ceramics toward High‐Performance Broadband NIR LEDs

Abstract

Near‐infrared (NIR) phosphor‐converted light‐emitting diodes (pc‐LEDs) are newly emergent broadband light sources for miniaturizing optical systems like spectrometers. However, traditional converters with NIR phosphors encapsulated by organic resins suffer from low external quantum efficiency (EQE), strong thermal quenching as well as low thermal conductivity, thus limiting the device efficiency and output power. Through pressureless crystallization from the designed aluminosilicate glasses, here broadband Near‐infrared (NIR) emitting translucent ceramics are developed with high EQE (59.5%) and excellent thermal stability (<10% intensity loss and negligible variation of emission profile at 150 °C) to serve as all‐inorganic visible‐to‐NIR converters. A high‐performance NIR phosphor‐converted light emitting diodes is further demonstrated with a record NIR photoelectric efficiency (output power) of 21.2% (62.6 mW) at 100 mA and a luminescence saturation threshold up to 184 W cm−2. The results can substantially expand the applications of pc‐LEDs, and may open up new opportunity to design efficient broadband emitting materials.

Locally-ordered A-site vacancy assisted photoluminescence enhancement in simply rare-earth doped perovskite oxide

“…Photoluminescence thermal stability, another technological parameter that is extremely important for phosphors, 39 was further explored. To this end, the V A -CST-0.02 phosphor showing the best PL property, and also its two strongest transitions, i.e.…”

Thermally stable and tunable broadband near-infrared emission from NIR-I to NIR-II in Bi-doped germanate glass for smart light sources

“…Cr 3+ ions within phosphors have been proven to be favorable NIR active centers and have shown their superiority to other activator ions in emission bandwidth (4150 nm), high internal quantum efficiency (IQE 4 90%), and effective blue light excitation. [18][19][20][21][22][23] However, the spectral region of Cr 3+ usually covers only the NIR I region (650-1000 nm), and it is still difficult to tune the emission peak of Cr 3+ beyond 1000 nm or longer in the NIR II region (1000-1700 nm). Light from the NIR-II region is more conducive to biological detection and imaging, real-time and nondestructive inspection due to its lower scattering and deeper penetration in biological tissues, and providing more information on relevant functional groups (such as O-H, C-H, and N-H bonds).…”

Broadband NIR Phosphor Ca2LuScAl2Si2O12:Cr3+ for NIR LED Applications

“…Nowadays, aluminosilicate NIR phosphors that have the garnet structure are designed to widen the FWHM and to improve the IQE, because aluminosilicate garnets have high thermal stability. [27][28][29] The general chemical formula of garnets can be summarized as M 3 X 2 Y 3 O 12 , where the coordination numbers of M, X, and Y are 8 (MO 8 dodecahedron), 6 (XO 6 octahedron), and 4 (YO 4 tetrahedron), respectively. The Cr 3+ ion occupying the octahedron site is the easiest way to emit NIR light.…”