OPTICAL MATERIALS
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2022
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IF 3.754
Yun Tang,Ben Liu,Nan Yan,Xiaoqiang He,Hudie Yuan,Yalou Xin,Hongfeng Yin
Widespread application of YAG:Ce-based white light-emitting diodes (WLEDs) is being challenged due to the lack of red emission, leading to their poor color rendering index (Ra) and high correlated color temperature (CCT). Perovskite quantum dots (QDs), presenting high photoluminescence quantum yield and simple fabrication process have been recognized as promising red-emitting component for warm WLEDs. However, conventional method by mechanically mixing QDs with YAG:Ce always results in undesirable dispersion due to their huge size difference. Moreover, the two components display different sinking behavior in silicone , which would further deteriorate the color uniformity of WLED. To address these issues, in this study, red-emitting MAPbBr 3-x I x QDs-coated YAG:Ce (A-YAG@QDs) composites were successfully prepared to further fabricate WLED with compensated red emission. The chemical coordination interactions between QDs and functionalized YAG:Ce make the two components behave as a whole, which effectively avoids the dispersion and sinking-related issues. The WLED, which combined blue LED chip and A-YAG@QDs composite, exhibited warm white light with low CCT of 4474 K, high Ra of 90.1 and high value of saturated red color component R9 as 95. This study demonstrated a promising strategy to prepare QDs-coated phosphor composites for the generation of warm white light for indoor lighting application.
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 ALLOYS AND COMPOUNDS
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2024
·
IF 5.8
Bobo Yang,Yuxuan Zhu,Weichen Li,Shiliang Mei,Rongrong Hu,Ruiqian Guo,Jun Zou
Perovskite quantum dots (QDs) glass has been considered as high efficiency, high color-purity, and high stability luminescent materials for display application. Herein, high emissive Dy doped CsPb(Br, I) 3 (CPBI: Dy) QDs glass has been prepared, and the effects of doping concentration on the crystallization behavior of QDs were discussed carefully. The low and high concentration of Dy doping brings diametrically opposite tuning effects for the emission wavelength. When high Dy doping, DyBO 3 nanocrystals were precipitated from the glass along with CPBI QDs. The highest photoluminescence quantum yield of CPBI: Dy QDs glass reached 53.79 %. The LEDs using the CPBI: Dy QDs glass as color converter could express pure-red light of 630 nm peak with a full width at half maximum of only 25.6 nm. What’s more, the color gamut of a white backlight unit based on prepared CPBI: Dy QDs glass film was 125.8 % of National Television System Committee color gamut standard and 94.0 % of Rec.2020, which has great potential in display application.
研究领域:
材料科学
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高影响因子
Materials Chemistry Frontiers
·
2024
·Vol. 8
·期 19
·3214-3222
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IF 6
Jiaqi Liu,Feng Zhang,Cuihe Fan,Zhengwei Cao,Yuying Hao
Perovskite quantum dots (QDs), with outstanding properties, including tunable emissions, high color purity, and low cost solution processability, have become promising candidates in light-emitting applications. However, the inherent instability issue strongly restricts further development and commercialization of light-emitting devices based on perovskite QDs. As well investigated in conventional QDs, the construction of QDs with core–shell structure is recognized as an effective way to improve the stability and optimize luminescent properties at the same time. Inspired by the unique structure diversity of perovskite materials, 2D/3D FAPbBr3@GA2PbBr4 QDs are proposed and fabricated through a one-step phase transfer enhanced emulsion synthesis. By systematically tuning the ratio between GABr and FABr as well as a combined analysis with X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, absorption and photoluminescence spectrum characterizations, a well-defined core–shell structure is demonstrated for FAPbBr3@GA2PbBr4 QDs under an appropriate ratio of GABr/FABr. Compared to the original QDs, the as fabricated core–shell QDs exhibit an enhanced exciton binding energy and improved stability under heat, light, and moisture exposure. Moreover, phosphor converted light-emitting diodes based on the core–shell QDs are also fabricated with a much improved device performance than that of QDs without a core–shell structure, proving the superiority of FAPbBr3@GA2PbBr4 QDs in light-emitting applications.
研究领域:
材料科学
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纳米技术
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光学工程
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化学合成
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DOI
高影响因子
DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 29
·10299-10309
·
IF 4.39
Hailin Che,Peipei Dang,Yi Wei,Ziyong Cheng,Jun Lin
All-inorganic cesium lead halide (CsPbX3, X = Cl, Br, and I) perovskite quantum dots (PQDs) have great potential application due to their unique optoelectronic properties. However, poor luminescence stability caused by some inevitable factors such as light, moisture and heat always restricts their practical application. In this work, the stability of CsPbX3 (X = Cl0.5Br0.5, Br, and Br0.5I0.5) PQDs is improved by encapsulating them in stable hollow mesoporous NaYF4:Yb,Tm nanoparticles (HMNPs). Compared to pristine PQDs, HMNP–PQD composites exhibit stable photoluminescence properties that can be maintained for more than 60 days under ambient atmospheric conditions. Thanks to the protection of HMNPs, the composites show much higher long-term stability in highly humid air and enhanced stability against UV light treatment compared to naked CsPbBr3 PQDs. Based on the proposed confinement effects of PQDs coordinated with the hollow mesoporous structure of NaYF4:Yb/Tm, the related structural model of NaYF4:Yb/Tm@PQD composites is discussed. Moreover, dual-mode luminescence can be observed in the NaYF4:Yb/Tm@PQD nanocomposites under 365 nm UV light and 980 nm laser excitation, indicating that the as-designed composites have great potential for dual-mode anti-counterfeiting application. This work provides a new idea for the stabilization and application of CsPbX3 PQDs.
研究领域:
材料科学
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光学
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纳米技术
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DOI
高影响因子
ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Wei Wan,Ya-Yun Zhou,Long Yan,Binbin Su,Shi Ye
Cesium lead halide (CsPbX3, X = Cl, Br, I) perovskite quantum dots (QDs) have been intriguing optoelectronic materials for applications in various devices owing to their superior electronic and optical properties. However, poor resistance to humidity and light irradiation impedes their promotion. Herein, bulk perovskite-type layered CsCa2Ta3O10 is exfoliated into two-dimensional (2D) negatively charged Ca2Ta3O10– (CTO) nanosheets as seeds to in situ synthesize and composite CsPbBr3. The as-synthesized CsPbBr3/CTO nanocomposites possess improved green emission with apparently prolonged decay time with reference to bare CsPbBr3 QDs. The decay time can retrieve to a normal state when the nanocomposites are treated with some water. It is found that the CTO acts as a defect to trap the bound exciton of the loaded CsPbBr3. Protons from water can preferably replace Cs+ at the interface of the nanocomposites, resulting in the separation of the nanosheets and CsPbBr3 and retrieving the decay time. X-ray photoelectron spectroscopy results also indicate the strong interaction between CsPbBr3 and CTO with reference to the physical mixing sample of bare CsPbBr3 QDs and CTO nanosheets. The decoration of ultrathin 2D charge-bearing oxide nanosheets on the QDs benefits significant improvements in humidity resistance and photostability performance in light-emitting diode devices. This research offers a distinct strategy to modify the surface of perovskite QDs.
研究领域:
材料科学
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光学工程
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DOI
PubMed
高影响因子
Light-Science & Applications
·
2024
·Vol. 13
·期 1
·1-11
·
IF 20.6
Liu Guangyou,Wu Xinzao,Xiong Feng,Yang Jinglan,Liu Yunhe,Liu Jie,Li Zhuohang,Qin Zong,Deng Shaozhi,Yang Bo-Ru
Traditional optical anti-counterfeiting (AC) is achieved by static printed images, which makes them susceptible to lower levels of security and easier replication. Therefore, it is essential to develop AC device with dynamic modulation for higher security. Electrophoretic display (EPD) has the advantages of low power consumption, high ambient contrast ratio, and capability of showing dynamic images which is suitable for dynamic AC applications. Herein, we prepared a dynamical AC device based on a fluorescent EPD, and achieving the image switch between black, white, and green fluorescence states under the dual-mode driving (electronic field and UV light). We loaded perovskite quantum dots (CsPbBr 3 ) onto the TiO 2 particles and further prepared fluorescent electrophoretic particles TiO 2 /CsPbBr 3 -3-PLMA (TiO/CPB-3) by grafting and polymerizing method. In addition, we fabricated the AC devices based on the fluorescent EPD, which exhibits the multifunctional AC, where the fluorescent EPD has a fast response time of 350 ms, a high contrast ratio of 17, and bright green fluorescence. This prototype demonstrates a new way for future dynamic AC and identification.
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 LUMINESCENCE
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2024
·
IF 3.3
Daqian Wu,Fengxian Zhou,Kai Feng,Jun Wang,Qixuan Lu,Xiaowu Wang,Zijun Zhan,Weiwei Chen,Zhengzheng Liu,Zeyu Zhang,Zhiping Hu,Juan Du
Lead halide perovskite quantum dots (QDs) have garnered significant attention due to their tunable band gaps, unique quantum confinement effects, and high photoluminescence quantum yields (PLQYs). Among them, Organic-inorganic QDs make them promising candidates for optoelectronic devices such as quantum dot light-emitting diodes (QLEDs), solar cells, lasers, and photodetectors. However, the toxicity of lead (Pb) has raised environmental and health concerns, hindering their industrial application. To alleviate concerns about heavy metals Pb, extensive research has been conducted on B-site doping and the development of lead-free perovskites. Herein, we firstly developed B-site doping strategy on organic-inorganic hybrid perovskite QDs via rare-earth elements. Neodymium (III) (Nd 3+ ) doped FAPbBr 3 QDs were prepared through the ligand-assisted reprecipitation method at room temperature. The B-site doping strategy could alleviate the heavy metal problem of Pb and modulate the band gap of FAPbBr 3 QDs facilely. The results demonstrated that increasing the concentration of Nd³⁺ can change the emission of FAPbBr₃ QDs from pure green to deep blue. Specifically, we achieved highly pure blue emission (∼438 nm) with a full width at half maximum (FWHM) of 13 nm for Nd³⁺-doped FAPbBr₃ QDs. Time-resolved photoluminescence (TRPL) spectroscopy revealed a decrease in the lifetime of FAPbBr₃ QDs from 22.86 to 15.46 ns as the doping concentration increased. Additionally, we fabricated a white LED (WLED) utilizing blue-emitting Nd³⁺-doped FAPbBr₃, green-emitting FAPbBr₃ QDs, and red QDs, achieving a white emission color coordinate of (0.33, 0.36). This study pioneers the application of B-site rare-earth doping in organic-inorganic hybrid perovskite QDs, demonstrating that B-site composition engineering is a reliable strategy to further exploit the perovskite family for wider optoelectronic applications.
研究领域:
材料科学
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光学工程
·
电子工程
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DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Enrou Mei,Xiaodong Liu,Ya Chen,Yanxia Yu,Zhaoping Chen,Keqin Yang,Xiaojuan Liang,Weidong Xiang
Recently, perovskite has received extensive attention due to their excellent photoelectric properties, while the instability of perovskite quantum dots (PQDs) has always troubled us. Herein, we proposed a simple coating mechanism to protect PQDs. Using oleic acid (OA) for etching α-Al 2 O 3 wafer to make the surface appear pore structure, and the PQDs was coated within the modified α-Al 2 O 3 wafer, thereby improving the stability of PQDs. The CsPbX 3 @α-Al 2 O 3 composite material can achieve the emission of blue-green–red (436 nm to 636 nm) through adjustable luminescence wavelength. The photoluminescence (PL) intensity of CsPbBr 3 @α-Al 2 O 3 composite material exposure to the air after 28 days can maintain over 50%. It is worth noticing that the photoluminescent quantum yield (PLQY) of CsPbBrI 2 @α-Al 2 O 3 composite material can reach 58%, the colour purity of CsPbBr 3 @α-Al 2 O 3 and CsPbBrI 2 @α-Al 2 O 3 achieve 97.1% and 99.8%, respectively. It was due to the high colour purity of the composite materials can the selected CIE colour coordinate monochromatic light encompassed 114% of NTSC colour gamut. Moreover, the warm white light-emitting diode (WLED) yielded bright natural white light and showed the luminous efficiency (LE) of 86.58 lm/W, colour rendering index (CRI) of 86.9, correlated colour temperature (CCT) of 4602 K. The LE and CRI reaches a relatively balanced value, which showed that this composite material has a certain development prospect in the WLED field.
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
Nanoscale
·
2016
·Vol. 8
·期 22
·11565-11570
·
IF 7.76
Dan Wang,Dan Wu,Di Dong,Wei Chen,Junjie Hao,Jing Qin,Bing Xu,Kai Wang,Xiaowei Sun
Compared to organic/inorganic hybrid perovskites, full inorganic perovskite quantum dots (QDs) exhibit higher stability. In this study, full inorganic CsPbX3 (X = Br, I and mixed halide systems Br/I) perovskite QDs have been synthesized and interestingly, these QDs showed highly polarized photoluminescence which is systematically studied for the first time. Furthermore, the polarization of CsPbI3 was as high as 0.36 in hexane and 0.40 as a film. The CsPbX3 perovskite QDs with high polarization properties indicate that they possess great potential for application in new generation displays with wide colour gamut and low power consumption.
研究领域:
材料科学
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光学
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DOI
PubMed
高影响因子
Nanomaterials
·
2024
·Vol. 14
·期 20
·1651
·
IF 4.4
Qi Yu,Wentian Sun,Shu Tang
CsPbIBr2, with its suitable bandgap, shows great potential as the top cell in tandem solar cells. Nonetheless, its further development is hindered by a high defect density, severe carrier recombination, and poor stability. In this study, CsPbI1.5Br1.5quantum dots were utilized as an additive in the ethyl acetate anti-solvent, while a layer of CsPbBr3QDs was introduced between the ETL and the CsPbIBr2light-harvester film. The combined effect of these two QDs enhanced the nucleation, crystallization, and growth of CsPbIBr2perovskite, yielding high-quality films characterized by an enlarged crystal size, reduced grain boundaries, and smooth surfaces. And a wider absorption range and better energy band alignment were achieved owing to the nano-size effect of QDs. These improvements led to a decreased defect density and the suppression of non-radiative recombination. Additionally, the presence of long-chain organic molecules in the QD solution promoted the formation of a hydrophobic surface, significantly enhancing the long-term stability of CsPbIBr2PSCs. Consequently, the devices achieved a PCE of 9.20% and maintained an initial efficiency of 85% after 60 days of storage in air. Thus, this strategy proves to be an effective approach for the preparation of efficient and stable CsPbIBr2PSCs.
研究领域:
材料科学
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能源科学
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DOI
PubMed
高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2023
·Vol. 25
·期 8
·1-11
·
IF 2.5
Dong Qi Zheng,Huang Xin Yi,Huang Cheng
A composite luminescent material consisting of perovskite quantum dots (PQDs) and MOF-5 using an in-situ growth method. The preparation of MOF-5 as a growth template was achieved via hydrothermal synthesis, with the addition of CTAB/TMB as a stencil agent to facilitate the formation of pores with an appropriate size. Subsequently, CsPbBr 3 QDs were grown in situ on the MOF under mechanical grinding conditions. The prepared CsPbBr 3 @MOF-5 composite materials were characterized by various analytical techniques including BET, XRD, PL, TEM, SEM, and EDS. The results revealed that the average size of PQDs was only 4.9 nm, and the corresponding emission peak exhibited a blue shift of 11 nm. The photoluminescence intensity (PL) of CsPbBr 3 @MOF-5 was increased by 71% compared to the unmodified sample, and photoluminescence quantum yield (PLQY) of solid powder increased to 48%. This is due to the fact that MOF-5 reduces the surface defects of quantum dots. Additionally, the Significantly improved PQDs stability after compounding MOF, both at room temperature and under thermal stress. These findings highlight the potential of this synthetic strategy as a means of preparing ultra-small composite light-emitting materials, with promising applications in LED and optoelectronic devices.
研究领域:
材料科学
·
光学
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DOI
高影响因子
Journal of Materials Chemistry C
·
2020
·Vol. 9
·期 6
·1983-1991
·
IF 7.059
Lin Yang,Bowen Fu,Xu Li,Hao Chen,Lili Li
All inorganic perovskite quantum dots (QDs) have received great attention owing to their excellent performance in optoelectronic applications. However, they often suffer from defect-related photoluminescence (PL) quenching and phase transformation due to the loss of long-chain organic ligands, such as oleic acid (OA) and oleylamine (OAm). Here, we fabricated CsPbBr3 QDs by a one-step microwave method, in the presence of α-phase poly(vinylidene fluoride) (PVDF) acing as the surface capping ligands. The PVDF-CsPbBr3 QDs display a photoluminescence quantum yield (PLQY) of up to 98% (much higher than pristine QDs with OA/OAm as capping ligands), excellent stability in the desired cubic phase structure, and enhanced photoluminescence stability under ambient conditions. Using the as-prepared QDs as a light emitter, the efficient green perovskite quantum-dot light-emitting diode (QLED) with an external quantum efficiency (EQE) of 1.71% was prepared, exhibiting a peak luminance of 5711 cd m−2 at 516 nm. Theoretical calculations indicate that there exists a much stronger interaction between the CsPbBr3(001) surface and PVDF as compared to OA/OAm ligands, further explicating sufficient surface passivation with the introduced PVDF ligand.
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材料科学
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光学
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高影响因子
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