CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Shengan He,Fanfan Xu,Tiantian Han,Zeqin Lu,Wei Wang,Jiaqing Peng,Fu Du,Fengli Yang,Xinyu Ye
Red-emitting phosphors composed of Mn 4+ -activated fluorides have attracted considerable interest for their applications in warm white light-emitting diodes (WLEDs). However, in addition to moisture instability, the unsatisfactory thermal stability of these phosphors limits their industrial applications. In this study, a novel red phosphor of CsMoO 2 F 3 :Mn 4+ was synthesized via simple coprecipitation. This red phosphor exhibits an orthorhombic structure with a bandgap of ~3.43 eV. The Mn 4+ ions occupy Mo 6+ sites at the centers of [MoO 2 F 4 ] 2− octahedrons. This phosphor shows narrow emission around ~633 nm excited by 450 nm blue-chip with high color purity of 99.58%. Satisfactorily, this phosphor exhibits excellent thermal stability and a strong negative-thermal-quenching. The total PL intensity of CsMoO 2 F 3 :3.88%Mn 4+ phosphor at 275 K strengthens to ~540% relative to that at 25 K, and its relative emission intensity preserves about 129.3% when the temperature rises from room temperature to 423 K (150 ℃). It also shows admirable color stability with a slight chromaticity shift ( ΔE ) of only ~ 33.9 × 10 - 3 in the temperature region from 298 to 473 K. Furthermore, a warm WLED was fabricated by the mixture of red-emitting CsMoO 2 F 3 :3.88%Mn 4+ and the yellow-emitting YAG:Ce 3+ phosphors with a blue-emitting InGaN LED chip. The device exhibits low correlated color temperature (3983 K) and high color-rendering index (Ra = 81.3). With the increasing drive current from 20 mA to 120 mA, the chromaticity coordinate variation (CCV) is only (−0.0163, 0.0202). All these results indicate that the CsMoO 2 F 3 :Mn 4+ phosphor holds tremendous potential for practical applications in high-power lighting and display with high-performance WLEDs.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
Advanced Science
·
2024
·Vol. 12
·期 4
·2408927
·
IF 14.3
Xiaochen Fang,Zhuo Chen,Mandy Hei Man Leung,Biao Zheng,Liwei Wang,Meng An,Yusuke Asakura,Yusuke Yamauchi,Zhanhui Yuan
Rare-earth-doped all-inorganic perovskite applications for near-infrared (NIR) emission are crucial for the construction of the next generation of intelligent lighting sources. However, the preparation of rare-earth-doped all-inorganic perovskite is complex, and difficult to control, and the issue of thermal quenching poses significant challenges to its practical application. Here, in order to address these issues, a convenient photo-induced synthesis method for CsPbCl 3 :Mn/Yb nanocrystals (NCs) is proposed by decomposing carbon tetrachloride with 365 nm light to provide chloride ions and regulate the formation of perovskite at room temperature. The negative thermal quenching in the NIR emission is achieved through the energy transfer between Mn and Yb. The emission intensity of Yb enhances 3.2 times when the temperature rises to ≈427 K. Furthermore, with the help of the orange emission from the Mn 2+ ions and the NIR emission from the Yb 3+ ions, visible to NIR light emitting diode (LED) devices are constructed and applied in orange light illumination and night vision imaging. This study enriches the preparation methods and chemical research on perovskite doping, which may open up new opportunities for the widespread application of perovskite-based materials or device engineering.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Haoli Ji,Xiaoru Dai,Wenyan Zheng,Chen Zhuang,Wenkun Dong,Dong Chen,Shisheng Ling,Xvsheng Qiao,Zhiyu Wang,Xianping Fan,Guodong Qian
Lanthanide-doped upconversion nanoparticles excel in many fields of applications due to their unique anti-Stokes spectroscopic properties, narrow emission bands, and high photochemical stability. Yb-based self-sensitized fluorides nanoparticles have higher absorption efficiency at 980 nm near-infrared laser than Y-based nanoparticles. This enhanced absorption makes NaYbF 4 an outstanding upconversion host material for pumping more photons to high-energy excited states of Tm 3+ that are rich in energy levels. For these purposes, NaYbF 4 :Tm nanoparticles seem to be more favorable for photoluminescence applications. In this study, size-adjustable NaYbF 4 :Tm nanoparticles were prepared using a high-temperature co-precipitation method. Under 980 nm excitation, the upconversion emission spectra appeared four emission bands in visible region. By increasing the size of nanoparticles, we well enhanced upconversion luminescence, indicating that surface quenching sites play a major role in inhibiting upconversion luminescence. In addition, the negative thermal quenching effect of NaYbF 4 :Tm nanoparticles was observed with temperature dependent luminescence spectra, and we found that smaller sized nanoparticles got stronger negative thermal enhancement and better temperature sensing performance. We fitted the luminescence intensity ratio (LIR) between the 1 D 2 → 3 F 4 (451 nm) and 1 G 4 → 3 F 4 (647 nm) transitions of Tm 3+ , where these nanoparticles exhibited both good absolute sensitivity S A (1.38% K −1 , at 453 K) and relative sensitivity S R (2.56% K −1 , at 293 K). These results suggested that NaYbF 4 :Tm nanoparticles could be a good candidate for thermometers even at high temperatures (up to 500 K).
研究领域:
材料科学
·
光学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2023
·Vol. 13
·期 8
·5428-5436
·
IF 3.9
Lu Yao,Hong Meng,Ming Liu
Copper-based perovskites, with lower electronic dimensions and high photoluminescence quantum yields (PLQY), which are non-toxic and thermally stable, have been reported since 2019 and have immediately attracted great attention. So far, only a few studies have researched the temperature-dependent photoluminescence properties, posing a challenge in ensuring the stability of the material. In this paper, the temperature-dependent photoluminescence properties have been investigated in detail, and a negative thermal quenching of all-inorganic CsCu2I3 perovskites has been studied. Moreover, the negative thermal quenching property can be tuned with the assistance of citric acid, which has not been reported before. The Huang–Rhys factors are calculated to be 46.32/38.31, which is higher than for many semiconductors and perovskites.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Materials Chemistry Frontiers
·
2022
·Vol. 6
·期 12
·1647-1657
·
IF 8.683
Huanhuan Zhang,Lin Yang,Hao Chen,Wenqiang Ma,Rui Wang,Guozhong Cao
Lead-free metal halides have gained considerable attention due to their excellent optoelectronic properties; however, the direct synthesis of white light sources remains a challenge for developing high-performance white light-emitting diodes (WLEDs). Herein, we synthesized all-inorganic copper-based ternary halides using a microwave method. Through a strategy of controlling the amount of cuprous iodide (CuI), two highly efficient light emitters, blue-emissive Cs3Cu2I5 and yellow-emissive CsCu2I3, can be obtained. The large Stokes-shifted broadband emission with a relatively long radiative lifetime is ascribed to the self-trapped exciton (STE) formation. The unique negative thermal quenching suggests that carrier transfer from more deeply trapped states to shallowly trapped states is beneficial for enhancing the STE emission. Moreover, with an increased amount of CuI, the as-synthesized Cs3Cu2I5@CsCu2I3 composites exhibit a series of stable cold/warm white-light emissions. The bright WLEDs ranging from cold-white (12810 K) to pure-white (6109 K) and warm-white (4149 K) are displayed by placing the Cs3Cu2I5@CsCu2I3 composite directly onto a commercial ultraviolet chip (310 nm), and an ultra-high color-rendering index (CRI) of 92 is achieved. The results imply that highly emissive and color-tunable copper-based halide composites open the door to explore their potential applications in next-generation solid-state lightings.
研究领域:
材料科学
·
光电学
·
光子学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2025
·Vol. 36
·期 20
·1-13
·
IF 2.8
Liu Chen,Ji Yulong,Feng Xia,Liu Jingsong,Shen Yichun,Xia Xuerong,Wang Lixi,Zhang Qitu
Lanthanide ion-doped Sc 2 Mo 3 O 12 upconversion (UC) luminescent materials exhibit a unique negative thermal quenching phenomenon, making them highly promising for applications in fluorescence thermometry. However, the luminescence intensity of Sc 2 Mo 3 O 12 phosphor is relatively low at room temperature, so it is urgently necessary to enhance the intensity of the phosphor at room temperature. In this study, Sc 2 Mo 3 O 12 :Yb/Er/Al phosphors were synthesized via the solid-state reaction method, and the effects of Al 3+ ion doping on their phase composition and upconversion fluorescence properties were investigated by X-ray diffraction (XRD) analysis and upconversion fluorescence spectra evaluation. The results show that the incorporation of Al 3+ ions enhanced the UC intensity at room temperature and improved the fluorescence thermometry performance. The doping of Al 3+ ions disrupts the lattice symmetry and reduces the distance between sensitizer ions (Yb 3+ ) and activator ions (Er 3+ ), increasing the UC intensity by approximately 4.2 times. In addition, the dependence of fluorescence properties of ScAl 0.6 Mo 3 O 12 :18%Yb 3+ /2%Er 3+ samples on temperature were tested, the negative thermal quenching effect was verified, and the thermal enhancement mechanism was explored. The maximum absolute and relative sensitivities of the ScAl 0.6 Mo 3 O 12 :18%Yb 3+ /2%Er 3+ reached 0.00635 K −1 at 372 K and 0.00829%K −1 at 300 K, respectively, indicating the potential of the phosphor for applications in optical thermometry.
研究领域:
材料科学
·
光学测温
·
固态物理
·
发光材料
·
掺杂技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）