Light-Science & Applications
·
2026
·Vol. 15
·期 1
·135
·
IF 24
Maimaitizi Hujiabudula,Ågren Hans,Chen Guanying
The development of pure-blue perovskite light-emitting diodes (PeLEDs) still lags behind that of green and red-emitting PeLEDs. Mixed halide (Br/Cl) perovskite nanocrystals (PeNCs) are commonly employed for blue emission but suffer from halide vacancies and ion migration. Here, we present a passivation strategy using the multifunctional fluorinated phosphonic acid molecule (1H,1H,2H,2H-heptadecafluorodec-1-yl)phosphonic acid (HFPA), which possesses active functional groups that improve the stability and electroluminescence performance of CsPb(Br/Cl) 3 NCs. The HFPA molecule is shown to interact with uncoordinated Pb 2+ on the PeNC surface through the phosphonate groups, concurrently establishing hydrogen bonds with adjacent halide ions. Moreover, the presence of fluorine atoms promotes ionic bond formation with the halide octahedra, thereby stabilizing the octahedral structure. The fabricated PeNC-LEDs exhibited a spectrally stable pure-blue emission peak at 467 nm, achieving a significantly improved external quantum efficiency (14.8%, 9-fold higher), maximum luminance (1052 cd·m -2 , 10-fold higher), and half-life (342 s, 13-fold higher) compared to the device fabricated with unmodified CsPb(Br/Cl) 3 NCs. Furthermore, the effective passivation of surface vacancies and stabilization of halogen ions by the HFPA molecules successfully suppressed ion migration in the PeNC-LEDs, thereby significantly enhancing the stability of the device.
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Catalysts
·
2023
·Vol. 13
·期 4
·751
·
IF 3.9
Jikun Chen,Yan Gu,Shishi Xu,Yunxiang Zhang,Zhe Zhang,Lin Shi,Zhichao Mu,Chenliang Zhou,Jiali Zhang,Qinfang Zhang
Developing efficient photocatalyst for the photoreduction of CO2and degradation of organic pollutants is an effective alternative to address increasingly serious energy problems and environmental pollution. Herein, the isostructural Sillén–Aurivillius oxyhalides, Bi7Fe2Ti2O17X (X = Cl, Br, and I; BFTOX), are fabricated for CO2reduction and degradation of organic pollutants for the first time. Density functional theory (DFT) calculations show that the valence band maximum (VBM) of BFTOC and BFTOB is contributed by the dispersive 2porbitals of O-atoms, providing the narrow band gap (Eg) and possibly the stability against self-decomposition deactivation. The photocatalytic activities of BFTOX are strongly affected by the halogens (Cl, Br, and I), namely, the BFTOCl sample displays outstanding activity improvement (3.74 μmol·g−1·h−1) for photocatalytic performance. This is mainly attributed to the high separation of charge carriers, small optical band gap, and extended optical absorption. This work focuses on affording a reference to develop efficient and stable photocatalysts from Sillén-Aurivillius layered oxyhalide materials.Keywords:Sillén–Aurivillius;Bi7Fe2Ti2O17X;photocatalyst;degradation;CO2reduction
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Advanced Optical Materials
·
2023
·Vol. 11
·期 9
·2203028
·
IF 9
Guozhen Li,Qiwen Pan,Zhihao Zhou,Ranran Gu,Hao Zhang,Xiongjian Huang,Guoping Dong,Xiudi Xiao
Perovskite CsPbX 3 (X = Cl, Br, I) nanocrystals with advantages of high quantum yield, narrow emission peaks, and tunable fluorescence are considered as the next generation of light-emitting sources. However, fluorescence degradation due to the poor stability of perovskite nanocrystals in moisture, high temperature, and illumination remains one of the greatest challenges in their further development. In this work, a fully dense coating strategy is proposed to improve the overall stability of perovskite nanocrystals, especially under high-density laser irradiation. A mesoporous silica SiO 2 layer is introduced to construct a stable coating for isolating the perovskite from external environment. To eliminate the pores of the CsPbX 3 @SiO 2 , an inorganic glass is also employed via solution-combustion technique to generate a fully compact encapsulation for further stability promotion. The as-prepared nanocrystal-in-glass composite exhibits efficient and stable fluorescence performance in luminous efficiency, chromaticity, and long-term reliability in the conditions of thermal shock, humidity, and blue laser irradiation. With the integration of red/green/blue emitting nanocrystals, the color gamut of the white laser lighting source covers 134% of the National Television Standards Committee standard, providing exciting opportunity for high performance laser-driven white light generation.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Le Ma,Xiansheng Li,Xuehan Chen,Jingyu Li,Pengfei Liu,Changting Wei,Qingshan Ma,Leimeng Xu,Wenhua Zhang,Jizhong Song
Mixed halide CsPb(Br/Cl) 3 quantum dots (QDs) exhibit fine tunable blue light and narrow photoluminescence (PL) full-width at half-maximum (FWHM), which has attracted significant attention as a promising candidate to realize a new generation of blue light technology. However, the introduction of Cl − makes it very easy to be eroded by water in the environment, which will lead to deep-level defects and degrade the luminescence and stability of QDs. Here, we propose to introduce tetra- n -octylammonium oxalate (TOAOxa) to improve the water-resistance stability and exciton recombination of CsPb(Br/Cl) 3 QDs and QD-based light-emitting diodes (QLEDs). The oxalate ion (Oxa 2− ) of TOAOxa could form strong interaction with undercoordinated Pb 2+ on CsPb(Br/Cl) 3 QD surface, which was confirmed by FTIR and XPS analysis. Oxa 2− passivated QDs (Oxa-QDs) exhibited improved photoluminescence quantum yield (PLQY) and enhanced water-resistance stability compared to pristine QDs. For example, after soaking in water–acetone co-solvent for 1 h, Oxa-QDs can maintain the initial cubic morphology and 43.9% of initial PL intensity, while the morphology and luminescence of pristine QDs are almost damaged. Based on the above concept, the Oxa-QD-based QLED presented a maximum external quantum efficiency (EQE) of 4.0%, and operational lifetime (T 50 ) of 84 s, which was a 5-fold enhancement in EQE, and 7-fold enhancement in stability compared to pristine QLED, respectively. Besides, the Oxa-QD-based QLED exhibits better stability in high-humidity air. To sum up, the Oxa 2− passivation strategy has significantly improved the efficiency and water-resistant stability of QDs and devices and would rapidly promote the development of blue-emitting QDs.
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MATERIALS RESEARCH BULLETIN
·
2022
·
IF 5.6
Mu Yang,Qilin Dai,Aiwei Tang,Feng Teng,Hong-shang Peng
Current chloride-bromine mixed perovskite quantum dots (PQDs) suffered from low luminescence efficiency and instability due to migration-nature of ionic species and high defect density. To tackle these challenges, herein a novel type of CH 3 NH 3 Pb(Cl/Br) 3 PQDs (Cl/Br-PQDs) were synthesized via a two-step method. Briefly, pristine silane-capped Br-PQDs were prepared, followed by anion exchange using oleylammonium chloride (OAm-Cl) and in-situ formation of silica shell. The optimal feeding ratio of Cl/Br was determined to be 1:1, which yielded colloidal Cl/Br-PQDs possessing a strong 464-nm emission, a high photoluminescence quantum yield of 94.6% and ultrahigh stability. The high quantum yield was attributed to efficient defects passivation by doped Cl − ions and silica-shell-locked OAm + ligands, whilst the high stability was to silica-shell-restricted migration of halogen ions. Such a combinational strategy of anion exchange and in-situ growth of silica shell may provide an effective solution for synthesis of mixed PQDs with high quality.
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JOURNAL OF LUMINESCENCE
·
2022
·
IF 4.171
Xiaobo Hu,Yanqiao Xu,Jiancheng Wang,Jiaxin Ma,Lianjun Wang,Wan Jiang
All-inorganic CsPbX 3 (X=Cl, Br, I) perovskite nanocrystals (NCs) exhibit attractive optoelectronic properties for lighting and displays application but suffer from the lack of profound insights into their reaction kinetics. Herein, a modified ligand-assisted reprecipitation (LARP) method was developed to synthesize high-quality CsPbBr 3 NCs by utilizing oleic acid (OA) and n-octylamine (OTAm) as surface ligands, and the effect of Cs/Pb ratio, precursors and ligands concentration on the structure, morphology and fluorescence properties was systematically investigated. The monodisperse CsPbBr 3 NCs with cubic shape and average particle size of 13.7 nm are obtained by optimizing the reaction parameters. Appropriately increasing the Cs/Pb ratio and precursors concentration to 0.5 and 1.0 mM are favorable for forming a more complete crystal structure with lower defect states density, which can significantly enhance the PL intensity. Notably, the surface defect states of CsPbBr 3 NCs are effectively passivated by the coordinated OA and OTAm ligands, and the maximum photoluminescence quantum yield (PLQY) can reach to 85.2%. Importantly, the effective synthesis of high-quality CsPbBr 3 NCs can be amplified up to 50 times of reaction volume after finely optimizing the reaction parameters. Based on a facile anion exchange process, the CsPbX 3 NCs with variable halogen composition exhibit tunable emission of 443.3∼649.1 nm and a wide color gamut of 117% NTSC standard. This work provides profound sights on the reaction kinetics of perovskite NCs, and further promotes its practical application in optoelectronic field.
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NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 46
·期 4
·1960-1971
·
IF 3.591
Wen He,Yongbo Xie,Qiang Yin,Zixuan Zhao,Lang Shi,Hongqing Wang
Scientists are still working on developing a “turn-on” fluorescence sensor for Co2+, especially in acidic solutions. A novel “on–off–on” fluorescence sensor based on g-C3N4 nanosheets was designed and prepared in this paper. It was able to detect (2-(5-bromo-2-pyridylazo)-5(diethylamino)phenol (abbreviated to 5-Br-PADAP) and Co2+ quantitatively by quenching and restoring the fluorescence of the g-C3N4 nanosheet system, respectively. Also discussed are the effects of solvent, pH, order of addition, and interaction time of 5-Br-PADAP and Co2+, as well as the concentration range of the object on measurement. Furthermore, in acidic conditions, the sensor demonstrated good selectivity and sensitivity. In the solvent system EtOH : H2O (v/v = 1 : 9, pH = 3), the fluorescence intensity had a good linear relationship with 5-Br-PADAP and Co2+ concentrations in the ranges of 0–15 μM and 0–10 μM, with low detection limits of 64 nM and 44 nM, respectively. Experiments and theoretical calculations were used to describe the interaction characteristics and sensing mechanism. It was eventually successful in detecting Co2+ in environmental samples.
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ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Heng Ban,Youdi Zhang,Shuaibo Chen,Youwei Cheng,Teng Pan,Lijun Wang,Xi Li
In this contribution, readily available 5-methyl furfural (MF) derived from biomass was used as an excellent substitute of the chemically unstable 5-hydroxymethylfurfural (HMF) for preparing the commercial precursor 2,5-furandicarboxylic acid (FDCA). MF was catalytically oxidized by air into FDCA in acetic acid over homogeneous Co/Mn/Br catalysts at 130–170 °C. It was found that both the substitute reactivity and the ring chemical stability have a remarkable impact on the yield of aromatic dicarboxylic acids. The effects of reaction temperature, pressure, catalyst composition and concentration, water concentration in the solvent, and substrate/solvent mass ratio on both the main reaction and the side reaction were investigated systematically and thoroughly using HPLC and an online tail gas monitoring system. Under optimized conditions, the oxidation of MF gave 100% conversion of MF and 75.8% yield of FDCA with 99.6% purity. It was also proven that the addition of 200 ppm cerium could work well at low temperatures (130–140 °C) for enhancing FDCA selectivity via suppressing the side reactions.
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OPTICAL MATERIALS
·
2019
·
IF 2.687
Jidong Deng,Jiao Xun,Rongxing He
All-inorganic cesium lead halide perovskite nanocrystals (NCs) are promising photoelectric materials for their high photoluminescence quantum yield (PLQY), narrow emission width and tunable optical band gap. Traditionally, the hot injection (HI) method has been utilized to prepare perovskite NCs. However, the HI method requires high temperature, protection under inert gas and other harsh synthetic conditions, which severely hinders large-scale production of these NCs. Herein, we directly synthesized CsPbBr 3 perovskite NCs by a modified LARP (ligand-assisted re-precipitation) approach, and then conducted a specific anion exchange reaction with inexpensive, readily available, non-toxic, and non-polluting KX (X = Cl, I) salts aqueous solution to obtain various compositions of CsPbX 3 perovskite NCs at room temperature (RT). The obtained RT-NCs have high PLQY and outstanding stability, and their photoluminescence can be precisely regulated across the whole visible region (419–670 nm). The use of inorganic salts for the ion exchange provides an efficient method for the design of various halogenated perovskite NCs and their large-scale synthesis at RT.
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NANOTECHNOLOGY
·
2018
·Vol. 30
·期 7
·075704
·
IF 3.404
Weiwei Chen,Xiaosheng Tang,Zhigang Zang,Yue Shi,Zhaoqi Yang,Juan Du
Doping of Mn2+ into semiconductor nanocrystals has been demonstrated to endow them with novel electronic, optical and magnetic functionalities. In this paper, Mn-doped CsPbX3 (X = Br, Cl) quantum dots (QDs) were synthesized at room temperature via a facile strategy by introducing dimethyl sulfoxide (DMSO)-MnBr2/PbX2 composite as a precursor. The excitonic emission spectra of the as-obtained Mn-doped CsPbX3 QDs can be tuned from 517 nm to 418 nm by adjusting the ratio of PbBr2/PbCl2 precisely, and the luminescence mechanism of the doped QDs is discussed in detail. Moreover, the highest photoluminescence quantum yield of the Mn2+ emission achieves 36.7%, which is comparable with QDs prepared by the conventional hot-injection method. Depending on the ratios of PbPb2/PbCl2, the energy transfer rate from the band-edge to Mn2+ excited state is in the range of 0.006–20.42 × 107 s−1. Furthermore, white light-emitting diodes (LEDs) were successfully fabricated by combining the as-prepared Mn-doped CsPbX3 QDs with commercial UV GaN chips, and the high luminous efficiency of the as-prepared white LEDs was developed to 55.9 lm W−1. This work strongly supports the fact that Mn-doped CsPbX3 QDs are promising materials for application in lighting and displaying fields.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2014
·
IF 2.045
Kelei Zhuo,Hao Ren,Yujing Wei,Yujuan Chen,Jingjing Ma
Activity coefficients of the 1-alkyl-3-methylimidazolium bromide [Cnmim]Br (n = 3 to 8) ionic liquids (ILs) in fructose + water mixed solvents at 298.15 K were determined by cell potential measurements. The molalities of [Cnmim]Br ranged from (0.005 to 0.1) mol·kg–1 and those of fructose from (0.2 to 0.8) mol·kg–1. Gibbs free energy interaction parameters were also obtained together with salt constants. The interactions between [Cnmim]Br and fructose are mainly controlled by electrostatic interactions. Gibbs free energy interaction parameters (gES) and salting constants (kS) are negative for the ILs (n = 3 to 6), indicating fructose are salted-in by the ILs in water, whereas fructose are salted-out by the ILs (n = 7 and 8).
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2013
·
IF 3.172
Guangfang Li,Fan Qin,Runming Wang,Shengqiang Xiao,Hongzhe Sun,Rong Chen
A facile microwave irradiation method has been successfully developed for the controllable fabrication of BiOX (X = Cl, Br, I) nanostructures in mannitol solution. The morphology and size of BiOX nanostructures could be readily tailored by adjusting the amount of halide, reaction precursor, and mannitol concentration. Mannitol molecule acts as both a capping agent and a cohesive agent in the formation of BiOX nanostructures. A possible two-stage formation mechanism was discussed based on the morphology evolution of BiOI nanostructures obtained in mannitol solution with different concentrations. The as-synthesized BiOX nanostructures exhibit much higher photocatalytic activities than that of commercial TiO 2 . In particular, flower-like BiOX hierarchical nanostructures display the best photocatalytic performance, which is mainly ascribed to their unique hierarchical structure, high BET surface area, and large band gap. Moreover, BiOX nanostructures also demonstrate superior Cr(VI) removal capacity. The Cr(VI) adsorption behavior was also analyzed by the Langmuir and Freundlich adsorption isotherms.
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危险品化学品经营许可证（带存储）