Host Dependency of Boundary between Strong and Weak Crystal Field Strength of Cr³⁺ Luminescence

The Journal of Physical Chemistry Letters, Journal Year: 2024, Volume and Issue: 15(9), P. 2319 - 2324

Published: Feb. 22, 2024

Cr3+ doped near-infrared phosphors hold significant applications and generate considerable research interest. The critical parameter for assessing the strength of crystal field in Tanabe–Sugano diagram is boundary value Dq/B, representing ratio splitting to Racah B. Nevertheless, there are conflicting values this parameter, as reported various studies, such 2.1, 2.2, 2.3 C/B = 4.5–4.8. Moreover, some with wide-band emissions exhibit a Dq/B that falls within region contradictory strong field. In study, we numerically determine which distinguishes between weak fields. results then demonstrate dependence on host material correlated parameters B C. This work resolves inconsistency emission profile Cr3+, providing researchers more profound comprehension luminescence.

Language: Английский

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Developing the Na₂CaZr₂Ge₃O₁₂:Cr³⁺ Garnet Phosphor for Advanced NIR pc-LEDs in Night Vision and Bioimaging

Chemistry of Materials, Journal Year: 2024, Volume and Issue: 36(9), P. 4654 - 4663

Published: May 1, 2024

Materials emitting near-infrared (NIR) light play a crucial role in the development of phosphor-converted light-emitting diodes (pc-LEDs) for applications ranging from fundamental science like spectroscopic analysis to highly applied uses night vision and biological imaging. One class materials that has garnered significant interest these technical spaces is Cr3+-activated garnets due their high efficiency ability operate at relatively temperatures. However, limited emission beyond 800 nm impedes use as optimal blue LED-pumped NIR-emitting materials. In this study, we present new garnet-type NIR phosphor, Na2CaZr2Ge3O12:Cr3+, addresses challenge─the material exhibits long-wavelength (λem,max = 832 nm) good thermal quenching resistance while maintaining an excellent internal quantum (IQE 98%). These properties are attributed crystal environment reconstruction, where structure distortion coupled weak field, which uncommon most rigid phosphors. Furthermore, fabricated pc-LED devices using demonstrate superior performance compared with employing well-known efficient phosphors operating range. The source subsequently demonstrated spanning vision, bioimaging, nondestructive analysis. This study not only provides insights into luminescence garnet desirable but also highlights practical application

Language: Английский

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Simultaneous NIR Emission and Thermal Stability Enhancement in Garnet‐Type NIR Phosphors through the Synergistic Effect of Lattice Distortion and Enhanced Rigidity

Laser & Photonics Review, Journal Year: 2024, Volume and Issue: 18(10)

Published: May 3, 2024

Abstract Even though there have been significant advancements in the development of Cr 3+ ‐activated near‐infrared (NIR) phosphors, challenge still remains to develop highly efficient and thermally stable NIR phosphors. Here, Ca 4‐x Zn x HfGe 3 O 12 :0.03Cr solid solution phosphors with 834–806 nm emission are constructed by substituting 2+ for , thereby facilitating formation [ZnO 6 ] luminescence site. The coexistence [HfO [Zn/CaO centers is confirmed through DFT calculation, time‐resolved photoluminescence (TRPL) spectroscopy, low‐temperature‐photoluminescence (77 K) spectroscopy. effectively resolves issue lattice mismatch between . Furthermore, simultaneous enhancement intensity thermal stability realized a synergistic combination distortion rigidity enhancement. By optimizing substitution concentration internal quantum efficiency (IQE) 92% an external (EQE) 29% finally achieved. Meanwhile, also enhanced from 59%@400 K (x = 0) 81%@400 0.8). developed phosphor‐converted light‐emitting diodes (pc‐LEDs) exhibit promising prospects fields security, biomedicine, non‐destructive testing rapid identification.

Language: Английский

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MTiTaO₆: Cr³⁺ (M = Al³⁺, Ga³⁺, Sc³⁺) Phosphors with Ultra‐Broadband Excitation Spectra and Enhanced Near‐Infrared Emission for Solar Cells

Laser & Photonics Review, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 29, 2025

Abstract Achieving ultra‐broadband absorption and enhancing the near‐infrared (NIR) emitting properties of NIR phosphors is a key challenge to realize its multiple applications, such as solar spectrum conversion, spectral analysis, night vision. Here, novel phosphor system MTiTaO 6 : Cr 3+ ( M = Al , Ga Sc ), with an excitation broad 421 nm enhanced emission reported. It widest among known ‐doped phosphors. Structural spectroscopic analysis shows that originates from overlap luminescence centers. Additionally, peak red‐shifted 816 871 increasing ion radius, intensity enhanced, which not only makes spectra more compatible response curve c‐Si cells, but also gives it advantage in spectroscopy applications. Comparison water alcohol demonstrate promising

Language: Английский

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Awakening the Dumb Site to Realize Ultra‐Broadband NIR Phosphor

Laser & Photonics Review, Journal Year: 2024, Volume and Issue: 18(5)

Published: Jan. 8, 2024

Abstract Near‐infrared (NIR) light sources have gained immense popularity in recent years due to their wide range of applications various fields, including spectroscopy and biomedical imaging. However, the limited emission bandwidth NIR phosphors is a significant bottleneck development. Here, novel strategy reported broaden by awakening dumb site. Na 4 M 3 Ta(PO ) 6 : Cr 3+ ( = Al , Ga In phosphor synthesized, which exhibits greatly broadened from 134 232 nm. Structural spectral analysis reveals that NaO octahedral site has severe t 2g ‐type distortion, making it for . By introducing larger at site, angular distortion decreases normal range, enabling luminescence again. Along with bandwidth, peak also redshifts 802 977 nm, giving advantages applications. Interestingly, awakened shows even better properties than original M/TaO These findings reveal insight into could potentially revolutionize design phosphors.

Language: Английский

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Multiple lattice sites occupied AlTaO4:Cr3+ phosphor for luminescence ratiometric thermometry and NIR light source

Journal of Alloys and Compounds, Journal Year: 2023, Volume and Issue: 970, P. 172544 - 172544

Published: Oct. 16, 2023

Language: Английский

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Efficient and Tunable Near-Infrared Luminescence in Cubic Phosphate K₂AlTi(PO₄)₃:Cr³⁺ for Spectroscopy Applications

ACS Applied Materials & Interfaces, Journal Year: 2024, Volume and Issue: 16(31), P. 41119 - 41126

Published: July 29, 2024

Broadband near-infrared (NIR) phosphors are crucial components of NIR phosphor-converted light-emitting diode (pc-LED) sources for various smart spectroscopy applications. However, developing an efficient, tunable, and inexpensive broadband phosphor with sufficient spectral coverage remains a great challenge. In this work, cubic phosphate K2AlTi(PO4)3 highly structural rigidity was chosen as host material Cr3+ substitution to create efficient emission. Synthesizing compound, the obtained exhibits emission covering 700–1200 nm peak wavelength ranging from 820 860 depending on substituting concentration. The concentration optimized sample possesses photoluminescence quantum yield (PLQY) 76.4% centered at 857 full width half-maximum (fwhm) 184 under 464 exaction, demonstrating relatively long-wavelength wide coverage. This is mainly derived single kind center deduced analysis, luminescence dynamics, first-principle calculations. Using material, fabricated pc-LED device presents excellent output power photoelectric conversion efficiency, making attractive in practical applications night-vision bioimaging. Therefore, work not only provides superiorities low cost, high wide-range tunability, coverage, but also highlights some clues discover materials.

Language: Английский

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发射峰为875 nm的高热稳定性立方相Sc(PO3)3:Cr3+荧光粉

Science China Materials, Journal Year: 2024, Volume and Issue: 67(3), P. 931 - 938

Published: Feb. 7, 2024

The compact size and high efficiency of near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) make them promising light sources in various fields, such as miniature NIR spectrometer. However, the current state phosphors with emission wavelengths exceeding 850 nm shows poor photoluminescence (PL) thermal stability. In this work, we present cubic-phase Sc(PO3)3:xCr3+ (x = 0, 1, 5, 10, 12, 14, 16 18 at%) that exhibit broadband ranging from 725 to 1150 nm, a peak at 875 nm. Particularly, PL intensity 5 at% sample retains 73.4% its value room temperature when measured 423 K, exhibiting exceptional stability compared previously reported peaks Through comparison investigation on variable-temperature X-ray diffraction patterns cubic- monoclinic-phase Sc(PO3)3:Cr3+ phosphors, it was revealed achieving good phosphor may be attributed minimal bond length angle variations elevated temperatures. fabricated pc-LEDs, driven 150-mA current, produce an radiant flux 26.62 mW. highest electro-optical conversion is 11.87% under drive 10 mA. This work provides insights for discovery Cr3+ ion-doped excellent

Language: Английский

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A Giant Stokes Shift in Wide‐Band Red Phosphor [Ca_0.33(Sr_1‐xBa_x)_0.67]₇(SiO₃)₆Cl₂: Eu²⁺

Advanced Optical Materials, Journal Year: 2024, Volume and Issue: 12(16)

Published: Feb. 22, 2024

Abstract This paper investigates a wide‐band emitting red phosphor, an advancement that solves shortcomings including the re‐absorption of yellow phosphor in blue light area and lack spectrum components which result low color rendering uneven white tone. An examination through femtosecond, Raman, low‐temperature spectroscopy demonstrates why this has large Stokes shift (SS = 7.5×10 3 cm −1 ) wide half‐peak width with full‐width at half maximum (FWHM) more than 170 nm. In these samples, it is importantly observed larger lattice causes smaller electron–phonon coupling Eu 2+ activator, meanwhile leads to less temperature dependency emission peak width. The obtained sample, after cation replacement (Ca 1‐x Sr x 7 (SiO 6 Cl 2 : (CSSC: ), exhibits covers range from 450 800 nm while its excitation below nm, not reabsorb light. matches well phosphors can also be excited by near‐ultraviolet chips. fabricated light‐emitting diode (w‐LED) device ideal index correlated (Ra 90.5, CCT 3894 K), making excellent candidate material for LED illumination.

Language: Английский

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Two-Site Occupation for Constructing Double Perovskite BaLaMgNbO₆:Cr³⁺ Ultrabroadband NIR Phosphors

Inorganic Chemistry, Journal Year: 2024, Volume and Issue: 63(19), P. 8899 - 8907

Published: May 2, 2024

Given the escalating significance of near-infrared (NIR) spectroscopy across industries, agriculture, and various domains, there is an imminent need to address development a novel generation intelligent NIR light sources. Here, series Cr3+-doped BaLaMgNbO6 (BLMN) ultrabroadband phosphor with coverage range 650–1300 nm were developed. The emission peak locates at 830 full width half maximum 210 nm. This originates from 4T2→4A2 transition Cr3+ simultaneous occupation [MgO6] [NbO6] octahedral sites confirmed by low photoluminescence spectra (77–250 K), time-resolved spectra, electron paramagnetic resonance spectra. fluxing strategy improves luminescence intensity thermal stability BLMN:0.02Cr3+ phosphors. internal quantum efficiency (IQE) 51%, external (EQE) can reach 33%, be maintained 60%@100 °C. Finally, we successfully demonstrated application BLMN:Cr3+ in qualitative analysis organic matter food freshness detection.

Language: Английский

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