Hidden Structural Evolution and Bond Valence Control in Near-Infrared Phosphors for Light-Emitting Diodes

Fang, Mu‐Huai; Chen, Kuan-Chun; Majewska, Natalia; Leśniewski, Tadeusz; Mahlik, Sebastian; Leniec, Grzegorz; Kaczmarek, S.M.; Yang, Cheng‐Ta; Lu, Kuang-Mao; Sheu, Hwo‐Shuenn; Liu, Ru‐Shi

doi:10.1021/acsenergylett.0c02373

Cited by 116 publications

(115 citation statements)

References 24 publications

Supporting

Mentioning

110

Contrasting

Order By: Relevance

“…In the PL spectra excited by blue light (λ ex = 445 nm), CLMSG:1%Cr 3+ shows broad NIR emission originated from 4 T 2g → 4 A 2g transition of Cr 3+ . [ 19–33 ] The broad NIR band peaks at 765 nm at RT. The peak blueshifts to 758 nm when the sample is cooled to 77 K. The blueshift should be caused by the strengthened crystal field due to the lattice shrinkage at a low temperature.…”

Section: Resultsmentioning

confidence: 99%

Thermally Stable CaLu₂Mg₂Si₃O₁₂:Cr³⁺ Phosphors for NIR LEDs

Liu

Yuan

et al. 2021

Advanced Optical Materials

Self Cite

View full text Add to dashboard Cite

Phosphor-converted (pc) white LEDs, generally installed in smartphones, are constructed by a single commercial blue LED and green/yellow/red phosphor powders. [12,13] Based on the mature pcLED technology, broadband NIR pcLED by employing phosphors that convert blue light to broadband NIR light is developed. [14,15] Commercial blue InGaN LEDs are efficient. [16] Using a single blue LED and NIR phosphors, a blue-NIR pcLED is the best solution to meet the needs of both compact dimensions and broadband NIR radiation. [17] Since the world's first broadband blue-NIR pcLED was produced by OSRAM at the end of 2016, [18] enormous progress has been achieved in broadband NIR phosphors that can be effectively stimulated by blue light. Comprehending kinds of reported NIR phosphors, Cr 3+ is believed to be one kind of the best activators due to its tuneable broadband and efficient NIR emission. [2,14,15,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] Correspondingly, the radiant power of NIR light was improved from 7-18.2 mW [25,33] to 43.1-81 mW [14,21,30,31] for the NIR pcLEDs driven at 350 mA. To achieve a high NIR radiation, the key is how to simultaneously possess a high efficiency and good thermal stability in NIR phosphors. The biggest challenge is how to discover a host that can depress the electron-phonon coupling (EPC) of Cr 3+ to the host.Garnets have been regarded as excellent hosts among lots of Cr 3+ doped NIR phosphors. Because garnets usually have a large bandgap that can depress the EPC of Cr 3+ to the host lattice. In addition a high efficiency, thus, Cr 3+ manifests high thermal stability in garnets, [27][28][29][30][31] such as the silicate garnet of Ca 3 Sc 2 Si 3 O 12 :Cr 3+ (CSSG:Cr 3+ ). [30] Herein, another silicate garnet of CaLu 2 Mg 2 Si 3 O 12 (CLMSG) that has a large bandgap (5.55 eV) is noted, [34] and Ce 3+ shows excellent luminescence in CLMSG for white LEDs. [34,35] In this work, we report the CLMSG:Cr 3+ NIR phosphor for the first time. Benefiting from the large bandgap and the weakened coupling of Cr 3+ to the CLMSG host, the optimized CLMSG:5%Cr 3+ has a characteristic of good thermal stability (≈92.1%@373 K). Correspondingly, the NIR radiation reaches 34.75 mW@100 mA for the fabricated tiny NIR pcLED.

show abstract

Section: Resultsmentioning

confidence: 99%

Thermally Stable CaLu₂Mg₂Si₃O₁₂:Cr³⁺ Phosphors for NIR LEDs

Liu

Yuan

et al. 2021

Advanced Optical Materials

Self Cite

View full text Add to dashboard Cite

show abstract

“…[7] However,r esearch focusing on the tunable photoluminescence (PL) properties of Cr 3+ -doped NIR-emitting phosphors is rare. [8] Previous studies have realized the PL tuning of Eu 2+ (f-d transition) and Bi 3+ (s-p transition) in the visible region by solid solution construction. [9] It can change the surrounding coordination environment of activators and thus realize optical tuning.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Broadening and Enhancement of Cr³⁺Photoluminescence in LiIn₂SbO₆by Chemical Unit Cosubstitution: Night‐Vision and Near‐Infrared Spectroscopy Detection Applications

et al. 2021

View full text Add to dashboard Cite

Near‐infrared (NIR)‐emitting phosphor materials have been extensively developed for optoelectronic and biomedical applications. Although Cr3+‐activated phosphors have been widely reported, it is challenging to achieve ultra‐broad and tunable NIR emission. Here, a new ultra‐broadband NIR‐emitting LiIn2SbO6:Cr3+ phosphor with emission peak at 965 nm and a full‐width at half maximum of 217 nm is reported. Controllable emission tuning from 965 to 892 nm is achieved by chemical unit cosubstitution of [Zn2+–Zn2+] for [Li+–In3+], which can be ascribed to the upshift of 4T2g energy level due to the strengthened crystal field. Moreover, the emission is greatly enhanced, and the FWHM reaches 235 nm. The as‐prepared luminescent tunable NIR‐emitting phosphors have demonstrated the potential in night‐vision and NIR spectroscopy techniques. This work proves the feasibility of chemical unit cosubstitution strategy in emission tuning of Cr3+‐doped phosphors, which can stimulate further studies on the emission‐tunable NIR‐emitting phosphor materials.

show abstract

“…Thus, great attentions have been drawn to develop broadband NIR phosphors that can be efficiently excited by blue light. [15][16][17][18] One strategy is to employ transition-mental ions, Cr 3+ for instance. [19][20][21] The main hosts for Cr 3+ -doped NIR phosphor are germanate, [22][23][24][25][26][27] silicate, [28][29][30][31][32] phosphate, [33][34][35] and borate.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, the NIR phosphor‐converted (pc) LED based on a commercial blue LED chip and broadband NIR phosphors is regarded as the best solution, because pc‐NIR‐LED has advantages of the compact structure and the broadband NIR emission. Thus, great attentions have been drawn to develop broadband NIR phosphors that can be efficiently excited by blue light 15‐18 …”

Section: Introductionmentioning

confidence: 99%

The hydrothermally synthesis of K₃AlF₆:Cr³⁺ NIR phosphor and its performance optimization based on phase control

et al. 2021

View full text Add to dashboard Cite

Near-infrared (NIR) spectroscopy has features of strong penetrability and the coincidence with the vibration frequency of many molecular bonds and has been widely used in fields of food detection, 1 night vision, 2-3 biological diagnosis, and imaging. [4][5] These applications also benefited from its advantages, such as convenience, nondestructive. [6][7][8][9][10] With the popularization of portable intelligent terminals, the integration of NIR technology into mobile phones has attracted a lot of attention. NIR light source includes tungsten halogen lamps and NIR LED chips. The tungsten halogen lamps have a very broad spectral scope, which make them to be available for detection in wide

show abstract

Hidden Structural Evolution and Bond Valence Control in Near-Infrared Phosphors for Light-Emitting Diodes

Cited by 116 publications

References 24 publications

Thermally Stable CaLu₂Mg₂Si₃O₁₂:Cr³⁺ Phosphors for NIR LEDs

Thermally Stable CaLu₂Mg₂Si₃O₁₂:Cr³⁺ Phosphors for NIR LEDs

Simultaneous Broadening and Enhancement of Cr³⁺Photoluminescence in LiIn₂SbO₆by Chemical Unit Cosubstitution: Night‐Vision and Near‐Infrared Spectroscopy Detection Applications

The hydrothermally synthesis of K₃AlF₆:Cr³⁺ NIR phosphor and its performance optimization based on phase control

Contact Info

Product

Resources

About

Hidden Structural Evolution and Bond Valence Control in Near-Infrared Phosphors for Light-Emitting Diodes

Cited by 116 publications

References 24 publications

Thermally Stable CaLu2Mg2Si3O12:Cr3+ Phosphors for NIR LEDs

Thermally Stable CaLu2Mg2Si3O12:Cr3+ Phosphors for NIR LEDs

Simultaneous Broadening and Enhancement of Cr3+Photoluminescence in LiIn2SbO6by Chemical Unit Cosubstitution: Night‐Vision and Near‐Infrared Spectroscopy Detection Applications

The hydrothermally synthesis of K3AlF6:Cr3+ NIR phosphor and its performance optimization based on phase control

Contact Info

Product

Resources

About

Thermally Stable CaLu₂Mg₂Si₃O₁₂:Cr³⁺ Phosphors for NIR LEDs

Thermally Stable CaLu₂Mg₂Si₃O₁₂:Cr³⁺ Phosphors for NIR LEDs

Simultaneous Broadening and Enhancement of Cr³⁺Photoluminescence in LiIn₂SbO₆by Chemical Unit Cosubstitution: Night‐Vision and Near‐Infrared Spectroscopy Detection Applications

The hydrothermally synthesis of K₃AlF₆:Cr³⁺ NIR phosphor and its performance optimization based on phase control