Photonics
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2023
·Vol. 10
·期 10
·1113
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IF 2.4
Junhu Cai,Xiaogang Chen,Wenyan Zhang,Longwen Yang,Zexi Lin,Wenxiao Zhao,Yun Ye,Sheng Xu,Tailiang Guo,Enguo Chen
Owing to their composition-tunable and narrow emissions and high photoluminescence quantum yield (PLQY), inorganic halide perovskite quantum dots (IPQDs) are a promising option for wide color gamut displays. However, their practical applications have been limited by their lattice structure instability and surface defect states. Herein, CsPbBr3:KBF4@SiO2with improved stability and optical properties is successfully synthesized with a two-step optimization of fluorine (F) anion doping and SiO2in situ coating. Compared with bromide (Br), higher electronegativity and a smaller radius of F lead to stronger binding energy with Pb2+. Also, F anions can occupy surface Br vacancies. Then, benefiting from the acidic environment provided by BF4−hydrolysis, tetraethyl orthosilicate (TEOS) can be more easily hydrolyzed on the CsPbBr3:KBF4surface to generate SiO2coating, thus further passivating lattice defects and improving environmental stability. Importantly, the PLQY of CsPbBr3:KBF4@SiO2achieves 85%, and the stability has been greatly improved compared with pure CsPbBr3. Finally, CsPbBr3:KBF4@SiO2/PDMS, CsPbI3/PDMS, and CsPbCl3/PDMS composites with narrow emissions are applied to replace traditional phosphors as color converters for direct-view light-emitting diode (LED) displays or liquid crystal display (LCD) backlights. The color gamut reaches 118.22% under the NTSC standard. Concerning the display field, it suggests likely applications in the future.Keywords:CsPbBr3;KBF4;SiO2;wide color gamut;liquid crystal displays;LED displays
研究领域:
材料科学
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光学工程
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高影响因子
Materials
·
2022
·Vol. 15
·期 6
·2177
·
IF 3.748
Wanjuan Tang,Qingfeng Guo,Ke Su,Haikun Liu,Yuanyuan Zhang,Lefu Mei,Libing Liao
Whitlockite has the advantages of a low sintering temperature, high stability, and a low fabrication cost, and it is widely used as the host for luminescent material. In this study, Ca1.8Li0.6La0.6−x(PO4)2:xDy3+phosphor was prepared by the high-temperature solid-state method, and its structure, composition, and luminescence properties were systematically studied. The results showed that a new whitlockite type matrix was prepared by replacing Ca2+in whitlockite with monovalent and trivalent cations. The prepared phosphors belonged to a hexagonal crystal system with a particle size in the range of 5–20 μm. Under the excitation of 350 nm UV light, the samples emitted white light, and there were mainly two stronger emission peaks at 481 nm in the blue band and 573 nm in the yellow band, which correspond to the electron transitions at4F9/2→6H15/2and4F9/2→6H13/2of Dy3+, respectively. The optimal doping concentration of Dy3+in Ca1.8Li0.6La0.6(PO4)2matrix was 0.03 (mol%). The main mechanism of concentration quenching in the sample was dipole–dipole energy transfer. When the temperature was 130 °C, the luminescence intensity of the samples was 78.7% of that at 30 °C, and their thermal quenching activation energy was 0.25 eV. The CIE coordinates of the sample at 30 °C were (0.2750, 0.3006), and their luminescent colors do not change with temperature. All the results indicate that Ca1.8Li0.6La0.6−x(PO4)2:xDy3+phosphor is a luminescent material with good luminescence performance and thermal stability, which shows a promising application in the field of LED display.Keywords:phosphor;whitlockite;Dy3+
研究领域:
材料科学
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光电
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发光材料
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PubMed
高影响因子
IEEE Photonics Journal
·
2025
·Vol. 17
·期 2
·1-7
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IF 2.4
Zong-Tao Li,Yi-Hua Qiu,Jia-Sheng Li,Jin-Cheng Li,Bin-Hai Yu,Xin Zhu,Xin-Rui Ding
Highly light-absorbed encapsulation is generally used to eliminate the ambient light for light-emitting diode (LED) display devices, it is challenging to simultaneously achieve a high ambient contrast ratio (ACR) and high light output efficiency (LOE). To solve this problem, we propose an inverted packaging structure for LED display devices. The LED chips’ emitting surface is mounted on the transparent carrier board (TCB) while the backside is packaged by the composite encapsulation, causing that the substrate is inverted to the topside of devices. As a result, the chips can emit light directly from the TCB and avoid the absorption loss of the encapsulation, leading to the high ACR and LOE performances. Compared to traditional devices, the inverted device showed an average increase of over 800% in luminous flux (LF) and LOE, and an average increase of over 390% in ACR. Additionally, the devices exhibited excellent soldering performance, corrosion resistance, airtightness, and thermal stability. This novel device overcomes the bottleneck of achieving both high ACR and high LOE, providing new insights for the development of LED display technology. Future work can further optimize the structure and materials of the TCB and composite encapsulation to enhance device performance.
研究领域:
光学工程
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材料科学
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电子工程
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高影响因子
JOURNAL OF RARE EARTHS
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2021
·
IF 3.712
Jiannan Jia,Mengting He,Jun Wan,Yuting Zhang,Hai Guo,Xianping Fan,Xusheng Qiao,Shiguo Chen
With narrow red photoluminescence (PL) bands, tetravalent Mn 4+ doped phosphors show promising prospect in commercial application to effectively expand color gamut of phosphor converted LED displays. Here, we report a type of Sr 2– z Mg 1+ y Y z Al 22– x O 36 : x Mn 4+ phosphors with regular cage-like micro-spherical morphologies. The micron size spherical precursors were synthesized with a propylene oxide (PO) driven fast sol–gel method. The cage -like spherical morphology is beneficial to efficiently trapping much incident light to enhance the PL of the phosphors. Being calcined at 1300 ° C, Sr 2 MgAl 21.978 O 36 :0.022Mn 4+ only exhibits the internal quantum efficiency (IQE) of 24.91%. With the Mg 2+ -Mn 4+ codoping and Y 3+ /Sr 2+ substituting strategies, to fulfill charge balance and produce John-Teller distortion, IQE of Sr 2– z Mg 1+ y Y z Al 22– x O 36 : x Mn 4+ can be further improved up to 36.45%. The CIE color coordinates of Sr 2– z Mg 1+ y Y z Al 22– x O 36 : x Mn 4+ under near ultraviolet excitation can be stably fixed to (0.723, 0.227) at deep red region. It thus finds a potential application as pc-LED display with much broader color gamut than that of the NTSC standard. Therefore, Sr 2– z Mg 1+ y Y z Al 22– x O 36 : x Mn 4+ micron size spheres can be employed as promising red phosphors for high performance LED displays.
研究领域:
材料科学
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光学工程
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高影响因子
Journal of Materials Chemistry C
·
2020
·Vol. 9
·期 6
·2047-2053
·
IF 7.059
Guojun Zhou,Zhiyang Liu,Maxim S. Molokeev,Zewen Xiao,Zhiguo Xia,Xian-Ming Zhang
Low-dimensional-networked metal halides are attractive for the screening of emitters applied in solid-state lighting and displays, but the lead toxicity and poor stability are obstacles that must be overcome in industrial applications. Herein, we aim at the discovery of bright and stable photoluminescence in zero-dimensional (0D) Mn2+-based metal halides. By manipulation of Cl/Br transmutation, the nature of the halogen can be confirmed as a pivotal factor to tune the PL behaviors, and the optimum Mn2+ emission with a high PLQY of 99.8% and a short lifetime of 0.372 ms can be achieved in (C24H20P)2MnBr4. The thermal quenching behaviors have been discussed in depth, indicating that the synergistic effect of good chemical stability of organic groups, a long Mn⋯Mn distance of 10.447 Å and a relatively large activation energy (ΔE = 0.277 eV) provides a platform for achieving excellent thermal stability in (C24H20P)2MnBr4. Moreover, the as-fabricated white LED device with a high luminous efficacy of 118.9 lm W−1 and a wide color gamut of 105.3% National Television System Committee (NTSC) shows that (C24H20P)2MnBr4 can be employed as a desirable narrow-band green emitter for LED displays. This work provides a new understanding of fine tailoring halogens, and proposes a feasible approach to achieving high thermal stability emitters toward the targeted practical applications.
研究领域:
材料科学
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光学工程
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DOI
高影响因子
JOURNAL OF LUMINESCENCE
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2024
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IF 3.3
Junhu Cai,Xiang Zhang,Yu Chen,Wenzong Lai,Wenyan Zhang,Zexi Lin,Yun Ye,Sheng Xu,Tailiang Guo,Jiajun Luo,Enguo Chen
Inorganic metal halide perovskite quantum dots (PQDs) have recently emerged as promising candidates for color conversion materials in Micro-LED displays, due to their outstanding color purity, high absorption coefficient, tunable emission wavelength . However the inferior stability and undesirable photoluminescence quantum yield (PLQY) restrict their particle applications. Herein, CsPbX 3 /PMMA (X = Br, I) composites with improved stability and optical performance were successfully prepared by a general and mild in-situ polymerization strategy. The ester carbonyl (C O) group in MMA formed complexes with Pb 2+ , leading to the in-situ thermal polymerization of polymethyl methacrylate (PMMA) under the action of the initiator. The multifunctional PMMA can efficiently passivate halogen vacancies while acting as a barrier against the degradation caused by heat, water, and oxygen. As a result, the PLQYs and stability of PMMA-coated CsPbX 3 PQDs have been significantly improved. When implementing CsPbX 3 /PMMA/PDMS composites as color conversion layers in Micro-LEDs, they achieve an impressive color gamut of 127.23% with excellent stability. We believe our work will stimulate the exploration of perovskite/polymer composites for industrial Micro-LED applications.
研究领域:
材料科学
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光学工程
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高影响因子
ACS Applied Engineering Materials
·
2024
·
IF 0
Zongtao Li,Zelong Li,Jiasheng Li,Guanwei Liang,Yaoxing Song,Xinrui Ding
While the active camouflage approach based on thermochromic materials in the visible–infrared spectrum achieves camouflage effects, it suffers from issues such as temperature-dependent color change, limited color range, and color nonuniformity, which undermine its reliability and applicability. This paper presents a visible–infrared active camouflage device comprising light-emitting diodes with a photothermal-scattering hybrid structure (PSHS-LED camouflage device), which includes a flexible LED display array, a photothermal conversion layer, and a flexible scattering layer. Herein, the employed photothermal conversion layer made of graphite-infused polydimethylsiloxane (PDMS) functions to convert a portion of visible light into heat which is emitted in the form of infrared radiation. At the same time, the selective scattering layer made of porous poly(methyl methacrylate) (PMMA), in which the incident visible light will be diffusely propagated, whereas infrared light undergoes minimal scattering. Finally, a visible–infrared active camouflage device enabling independent control of visible-light and infrared imaging is obtained, ensuring effective camouflage in the visible–infrared detection domain. The manufactured PSHS-LED camouflage device exhibits a distinctly discernible infrared imaging effect when the infrared detector is sufficiently close, with a maximum temperature difference of 15 °C within the device. Meanwhile, the manufactured PSHS-LED camouflage device exhibits a wide color gamut (102% of the Adobe RGB gamut) and uniform display performance, offering a viable solution for visible–infrared active camouflage.
研究领域:
材料科学
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光学工程
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电子工程
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DOI
Science China-Materials
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2025
·
IF 7.4
Yang Chen,Tan Yuhuan,Li Zheyi,Liang Shan,Guan Xi-Hua,Yang Zhong-Jian,Lian Shixun,Zhou Wenli
The reduction in photoluminescence efficiency due to crystallite downsizing is a significant issue in Mn 4+ -doped fluoride nanomaterials, crucial for their application in full-color micro-LED displays. This study presents a strategy to enhance the photoluminescence efficiency of K 3 AlF 6 :Mn 4+ nanocrystals (NCs) by incorporating Mg 2+ for charge compensation and utilizing the plasmonic effect of Au nanorods. We found that Mg 2+ incorporation effectively reduced lattice defects, increasing photoluminescence intensity by 17% and internal quantum efficiency from 22.37% to 27.56%. Fabricating Au@SiO 2 /fluoride nanocomposites, we investigated how the SiO 2 spacer layer thickness, Au@SiO 2 resonance wavelength, and relative concentration affect photoluminescence properties. Optimizing the balance between Purcell and Förster resonance energy transfer effects further increased photoluminescence intensity by 25%, internal quantum efficiency to 32.09%, and external quantum efficiency from 14.20% to 18.05%. Additionally, we assessed the potential application of these nanocomposites in micro-LED display technology by examining nanocomposite-PMMA films. This work provides insights into the development of highly efficient red-emitting nanomaterials.
研究领域:
材料科学
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光学工程
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高影响因子
INORGANIC CHEMISTRY
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2017
·
IF 4.857
Zhenyue Wu,Lina Li,Chengmin Ji,Guoming Lin,Sasa Wang,Yaoguo Shen,Zhihua Sun,Sangen Zhao,Junhua Luo
Organic–inorganic hybrid lead halide (e.g., CH3NH3PbX3, where X = CI, Br, and I) nanowires (NWs) with remarkable electric and optical properties have recently garnered increasing attention, owing to their structural flexibility and tunability compared to inorganic semiconducting NWs. While most recently reported NWs are limited to methylammonium/formamidinium three-dimensional lead halide perovskites, it is urgent to develop new organic–inorganic hybrid semiconducting NWs. Here, broad-band-emissive single-crystal semiconductive NWs based on a new ABX3-type organic–inorganic chain hybrid, (2-methylpiperidine)lead tribromide, are reported. It is believed that this work will enrich the organic–inorganic hybrid semiconducting NWs and may provide potential applications for LED displaying.
研究领域:
材料科学
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半导体物理
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纳米技术
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光电
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PubMed
高影响因子
ACS Photonics
·
2025
·
IF 6.7
Zijun Yan,Yuhui Wang,Shibiao Liu,Wenan Guo,Guolong Chen,Xiaotong Fan,Yue Lin,Shuli Wang,Hao-Chung Kuo,Zhong Chen,Tingzhu Wu
Quantum dot (QD) color conversion layers (CCLs) present an economical and reliable approach to achieve full-color micro-LED displays. Microfluidic technology demonstrates significant advantages for patterning and integrating multicolor QDs, including high precision, rapid processing, low material consumption, and low fabrication costs. However, preparing high-resolution CCLs with low optical crosstalk remains challenging due to limitations in microfluidic chip design induced by swelling of polydimethylsiloxane (PDMS) microchannels in nonpolar solvents utilized for QD dispersion. In this study, we developed a QD solution with a polymer additive that effectively suppresses PDMS swelling, making injection of QD solution into small-sized PDMS microchannels on chromium-patterned microhole glass substrates possible. The resulting QD CCLs exhibit high luminescence uniformity and a high resolution of 1285 ppi, with a subpixel dimension of 5 μm × 5 μm, which is the smallest dimension reported for CCLs fabricated by microfluidic technology. Furthermore, our innovative integration of chromium-patterned microhole glass substrates within a microfluidic device provides unprecedented optical isolation, effectively eliminating intersubpixel crosstalk in CCLs. By integrating optimized red and green QD CCLs with a blue GaN micro-LED array, we successfully fabricated a full-color micro-LED prototype with a resolution of 600 ppi and a wide color gamut of 115% NTSC. Owing to their high resolution, uniform luminescence, and low optical crosstalk, the proposed microfluidic technology holds significant promise for advancing next-generation full-color micro-LED displays.
研究领域:
材料科学
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纳米技术
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显示技术
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微流控技术
·
光电子学
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DOI
高影响因子
Nano Energy
·
2022
·
IF 19.069
Tongtong Xuan,Shaoqiang Guo,Wenhao Bai,Tianliang Zhou,Le Wang,Rong-Jun Xie
Although tremendous efforts have been made to enhance the stability of lead halide perovskite quantum dots (PeQDs), they cannot meet the long-term requirements of photoelectric devices due to their poor reliability when attacked by multiple factors. Herein, we report ultrastable CsPbBr 3 :Sr/PbBr(OH)/molecular sieve composites with a high photoluminescence quantum yield of 75% and high overall stability when exposed to water, blue light and heat, owing to (i) the increased formation energy of CsPbBr 3 PeQDs by Sr doping and (ii) good encapsulation by PbBr(OH) and molecular sieves. These composites maintain 54% of their initial intensity after being aged at 85 °C and 150 mW cm −2 for 720 min, which is superior to commercial green CdSe-based QDs. These promising composites are then used to produce Mini-LED backlights with a high luminous efficacy of 86 lm/W and a color area of ~124% of the National Television Standards Committee or 93% of the Rec. 2020 standards by combining them with red CdSe/CdS/ZnS QDs and a blue Mini-LED chip. We believe that highly reliable PeQDs can be achieved by building well-designed composite structures, thus enabling them to be practically applied in emerging lighting and displays.
研究领域:
材料科学
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光电技术
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高影响因子
危险品化学品经营许可证（带存储）