A green synthetic route to K2NbF7:Mn4+ red phosphor for the application in warm white LED devices

Ming, Hong; Zhang, Junfei; Liu, Shuifu; Jie, Peng; Du, Fu; Huang, Jingyu; Xia, Libin; Ye, Xinyu

doi:10.1016/j.optmat.2018.10.031

Cited by 30 publications

(9 citation statements)

References 48 publications

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“…[41][42][43] To further investigate the coordination environment which greatly affects the luminescence property of doping Mn 4+ , the polyhedral distortion index (D) was calculated based on the following Equation 44 : [41][42][43] To further investigate the coordination environment which greatly affects the luminescence property of doping Mn 4+ , the polyhedral distortion index (D) was calculated based on the following Equation 44 :…”

Section: Resultsmentioning

confidence: 99%

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Insight into a novel rare‐earth‐free red‐emitting phosphor Li₃Mg₂NbO₆:Mn⁴⁺: Structure and luminescence properties

et al. 2019

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Red phosphor is indispensable to achieve warm white light in the white light diode (WLED) application. However, the current red phosphors suffer from high cost and harsh synthesis conditions. In this study, an oxide-based rare-earth-free red-emitting phosphor Li 3 Mg 2 NbO 6 :Mn 4+ (LMN:Mn 4+ ) has been successfully synthesized by a simple solid-state reaction method. The relationship between crystal structure and luminescence was investigated in detail. The site occupancy of the doping Mn 4+ ion in the LMN host has been discussed from the point of bond valence sum. How the coordination environment of doping Mn 4+ affects the energy level of doping Mn 4+ ion has been illustrated via the Tanabe-Sugano energy-level diagram. Moreover, warm white light has been obtained using LMN:Mn 4+ as compensator to the YAG:Ce 3+ . K E Y W O R D Scalculation, luminescence materials, Mn 4+ , phosphor, photoluminescence

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Section: Resultsmentioning

confidence: 99%

“…O to compensate charge unbalances, which is similar to other cases. [41][42][43] To further investigate the coordination environment which greatly affects the luminescence property of doping Mn 4+ , the polyhedral distortion index (D) was calculated based on the following Equation 44 :…”

Section: Resultsmentioning

confidence: 99%

Insight into a novel rare‐earth‐free red‐emitting phosphor Li₃Mg₂NbO₆:Mn⁴⁺: Structure and luminescence properties

et al. 2019

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“…HF is known to have hypertoxicity and can potentially lead to severe damages to the human body. 22,23 In addition, the extra demands for safety precautions and the post-treatment of HF waste liquid will inevitably increase phosphor costs. Therefore, an HF-free green synthesis route of NIR fluoride phosphors is in urgent need in consideration of the abovementioned safety and environmental issues.…”

Section: Introductionmentioning

confidence: 99%

Green HF-Free Synthetic Route to the High-Efficiency K₂NaGaF₆:Cr³⁺ Phosphor and Its NIR-LED Application toward Veins Imaging

Yang

Liu

et al. 2022

ACS Sustainable Chem. Eng.

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Cr 3+ -activated phosphors with highly efficient broadband nearinfrared (NIR) emission and superb thermal stability have been regarded as ideal candidates for next-generation NIR radiation sources. Nevertheless, the requirements of toxic and concentrated HF during syntheses of fluoride phosphors could lead to dramatic environmental and safety concerns. In this work, we developed a feasible HF-free green synthesis method to prepare K 2 NaGaF 6 :Cr 3+ with high-efficiency NIR broadband emission using an aqueous solution instead of HF. The X-ray diffraction analyses and microscopy images all suggested the successful synthesis of the target materials without impurities. Theoretical simulations based on the density functional theory have also indicated a sufficient band gap of K 2 NaGaF 6 as the host matrix for the Cr 3+ activator. The luminescent properties of K 2 NaGaF 6 :Cr 3+ were investigated in detail, where the optimum Cr 3+ doping concentration was found at ∼6 mol %. Moreover, the temperature-dependent spectra revealed an excellent thermal stability of K 2 NaGaF 6 :Cr 3+ , where the luminescent intensity at 150 °C can retain as much as 91% of the initial value at the room temperature. These characteristics make K 2 NaGaF 6 :Cr 3+ an ideal phosphor for phosphor-converted NIR light-emitting diodes. Therefore, device fabrication was carried out for venography demonstration, which shows superb imaging performance of human vessels and tissues.

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“…The Mn 4+ ‐activated fluoride phosphors have been attracted more and more attentions recently . Mn 4+ is a transition metal ion with 3d 3 external electronic structure.…”

Section: Introductionmentioning

confidence: 99%

“…10 The Mn 4+ -activated fluoride phosphors have been attracted more and more attentions recently. 7,[11][12][13][14][15][16][17] Mn 4+ is a transition metal ion with 3d 3 external electronic structure. The broad excitation and narrow emission band of Mn 4+ as the consequence of its unique electronic configuration makes it proper for red phosphors.…”

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confidence: 99%

Comparative analysis on the photoluminescence properties of Cs₂BF₆:Mn⁴⁺ (B = Ge, Si, Zr, Ti) red phosphors for WLEDs

et al. 2019

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A series of Cs2BF6:Mn4+ (B = Ge, Si, Ti, Zr) red phosphors were synthesized by a precipitation‐cation exchange route. The phase purity, morphology, and constituent were characterized by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). Optical properties were investigated by photoluminescence (PL) spectra and high‐resolution PL. Temperature‐dependent PL examination at the range of both 273‐573 K and 10‐300 K was performed to investigate the emission mechanism of Mn4+ in these fluorides. The intensity for both zero‐phonon lines (ZPLs) and vibration coupled emission of Mn4+ in these four systems with different crystal structures was investigated systematically. These phosphors present bright red emission under blue light (467 nm) illumination, among which Cs2GeF6:0.1Mn4+ shows the highest emission intensity with ultrahigh quantum efficiency of 94%. The white light‐emitting diodes (WLEDs) fabricated with this sample, blue InGaN chips and commercial YAG:Ce3+ phosphor exhibited high luminous efficacy beyond 100 lm/w with high color rendering index (~88.6) and low color temperature (~3684 K).

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A green synthetic route to K2NbF7:Mn4+ red phosphor for the application in warm white LED devices

Cited by 30 publications

References 48 publications

Insight into a novel rare‐earth‐free red‐emitting phosphor Li₃Mg₂NbO₆:Mn⁴⁺: Structure and luminescence properties

Insight into a novel rare‐earth‐free red‐emitting phosphor Li₃Mg₂NbO₆:Mn⁴⁺: Structure and luminescence properties

Green HF-Free Synthetic Route to the High-Efficiency K₂NaGaF₆:Cr³⁺ Phosphor and Its NIR-LED Application toward Veins Imaging

Comparative analysis on the photoluminescence properties of Cs₂BF₆:Mn⁴⁺ (B = Ge, Si, Zr, Ti) red phosphors for WLEDs

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A green synthetic route to K2NbF7:Mn4+ red phosphor for the application in warm white LED devices

Cited by 30 publications

References 48 publications

Insight into a novel rare‐earth‐free red‐emitting phosphor Li3Mg2NbO6:Mn4+: Structure and luminescence properties

Insight into a novel rare‐earth‐free red‐emitting phosphor Li3Mg2NbO6:Mn4+: Structure and luminescence properties

Green HF-Free Synthetic Route to the High-Efficiency K2NaGaF6:Cr3+ Phosphor and Its NIR-LED Application toward Veins Imaging

Comparative analysis on the photoluminescence properties of Cs2BF6:Mn4+ (B = Ge, Si, Zr, Ti) red phosphors for WLEDs

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Insight into a novel rare‐earth‐free red‐emitting phosphor Li₃Mg₂NbO₆:Mn⁴⁺: Structure and luminescence properties

Insight into a novel rare‐earth‐free red‐emitting phosphor Li₃Mg₂NbO₆:Mn⁴⁺: Structure and luminescence properties

Green HF-Free Synthetic Route to the High-Efficiency K₂NaGaF₆:Cr³⁺ Phosphor and Its NIR-LED Application toward Veins Imaging

Comparative analysis on the photoluminescence properties of Cs₂BF₆:Mn⁴⁺ (B = Ge, Si, Zr, Ti) red phosphors for WLEDs