ACS Applied Materials & Interfaces
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2022
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IF 10.383
Zhenyu Wang,Xinyu Shen,Chengyuan Tang,Xin Li,Junhua Hu,Jinyang Zhu,William W. Yu,Hongwei Song,Xue Bai
Oleylamine and oleic acid are common organic capping ligands used in the hot injection preparation of perovskite quantum dots (QDs). Their labile nature is responsible for the poor colloidal stability and conductivity that affect the performance of perovskite QD light-emitting diodes (LEDs). We introduced 4-trifluoro phenethylammonium iodide (CF3PEAI) directly in the synthesis and found that CF3PEAI efficiently modified the I– vacancy defects on the QD surface and partially substituted the surface capping ligand oleylamine. The strong electron pulling ability of F in CF3PEAI results in a more positive −NH3+ terminal compared to that of PEAI, which promotes tight bonding of CF3PEAI on the surface of CsPbI3 QDs. As a result, we achieved bright QDs with a photoluminescence quantum yield of 92% and efficient red LEDs. The maximal luminance was improved to 4550 cd m–2 for 685 nm red light, which was nearly 4.6-fold of the LEDs with plain CsPbI3 QDs. Additionally, the peak external quantum efficiency reached 12.5%.
研究领域:
材料科学
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光电技术
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DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
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2025
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IF 5.6
Yuang Chen,Yang Zou,Lili Zhao,Zijian Lei,Lixin Song
Point defect has a significant impact on the optical properties of materials. The light absorption behavior can be changed through adjusting the concentration of point defect. Here, nonequilibrium surface oxygen vacancy is firstly introduced into MgTiO 3 material and then eliminated under laser irradiation to realize an optical transformation from high absorption to high reflectivity among a wide range of wavelength. NaBH 4 low-temperature reduction treatment is conducted to control the distribution of oxygen vacancy. MgTiO 3 @MgTiO 3-x core-shell structure is fabricated through the treatment, in which disordered MgTiO 3-x with high-concentration of oxygen vacancy forms a shell covering a highly crystalline MgTiO 3 core. The reflectivity is reduced to 5 % among 400–2500 nm due to the interconduction subband absorption of the metallized disordered MgTiO 3-x shell. Research shows that the core-shell structure is beneficial for enhancing the transformation rate owing to the short diffusion distance. Remarkably, under 100 W cm −2 1064 nm laser irradiation, the nonequilibrium surface oxygen vacancy can be eliminated in a short time and the material will transform to high-reflectivity state in 1000 ms, with the reflectivity restoring to 83 %.
研究领域:
材料科学
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光学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2018
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IF 11.698
Xin Xiao,Chunxia Zheng,Mingli Lu,Ling Zhang,Fei Liu,Xiaoxi Zuo,Junmin Nan
The selective oxidation of benzyl alcohol (BA) into benzaldehyde (BAD) is an attractive model reaction for organic synthesis. Using a microwave-calcination route, a novel flower-like Bi 24 O 31 Br 10 with surface oxygen vacancies and bromine vacancies was successfully synthesized. In the construction of Bi 24 O 31 Br 10 , glucose acts as a complexing, reducing, and structure-directing agent. The as-synthesized Bi 24 O 31 Br 10 exhibits excellent activity for the photocatalytic aerobic oxidation of BA into BAD, with >99% conversion and >99% selectivity under blue LED irradiation at ambient conditions, which is 3.3-, 4.7-, and 27.8-fold higher than that of TiO 2 , Bi 4 O 5 Br 2 , and Bi 12 O 17 Cl 2 , respectively. The high selectivity is due to the suitable energy band of the as-synthesized Bi 24 O 31 Br 10 (E g = 2.51 eV, valence band potential = +2.38 V), while the high conversion rate is largely due to the efficient separation of photogenerated carriers, surface defects, positively charge surface, and 3D micro/nano-architecture. The primary active species, including h + , e − , O 2 − , and OH, are all involved in the photoreaction. On the basis of experimental results and quantum-chemistry calculations, a direct hole oxidative mechanism with two-step dehydrogenation pathway was suggested. In addition, the as-synthesized Bi 24 O 31 Br 10 catalyst remains stable during the photocatalytic process, indicating its potential for practical applications.
研究领域:
材料科学
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化学工程
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环境科学
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DOI
高影响因子
MATERIALS RESEARCH BULLETIN
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2021
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IF 4.641
Xinshan Rong,Shixian Zhang,Jian Rong,Jing Wei,Xuchun Qiu,Zhiren Wu
Z-scheme nitrogen-deficient graphitic carbon nitride/ferric oxide (GCN x /FO) photocatalysts were obtained by a one-step calcination method. The number of nitrogen defects was tuned by the application of KOH, while the ferric oxide phase and magnetism was controlled by the usage of ferrous oxalate. Interconversion between the hematite (α) and maghemite (γ) phases of Fe 2 O 3 was analyzed by X-ray diffraction, and magnetism of the GCN x -0.1/FO products provided via vibrating sample magnetometer test. The introduction of nitrogen defects narrowed the bandgap and extended the spectral range of light absorption while improving the ability to capture and activate N 2 effectively. Surface defects were employed as active sites, and the ammonia generation concentration reached approximately 69.7 μmol/L/h by N 2 photofixation under visible light. Due to their ease of synthesis and tuning, high photocatalytic activity, convenient and rapid collection for reuse, and excellent stability, GCN x /FO composited photocatalysts possess vast potential for use in clean ammonia production.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
Environmental Science-Nano
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2018
·Vol. 5
·期 11
·2570-2578
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IF 6.087
Xinwen Ou,Xueming Liu,Weizhen Liu,Wencong Rong,Jingyuan Li,Zhang Lin
The surface defects of adsorbents are generally considered to be the active sites for adsorbates, and the adsorption behaviors of a variety of pollutants in wastewater are strongly influenced by the surface defects of the adsorbents. With simple chemical and structural properties, nano-Mg(OH)2 exhibits a high adsorption affinity and selectivity to heavy metals from wastewater. The insight into the surface complex structures of heavy metals on the Mg(OH)2 surface is fundamental for both the mechanism and application of defective adsorbents in wastewater treatment. In this study, the impact of surface defects of Mg(OH)2 nanoplates on the structure, energy, and adsorption amounts of toxic heavy metal oxyanions (HAsO42− and CrO42−) was investigated by combining the first-principles calculations and batch experiments. The first-principles calculations illustrated that the heavy metal oxyanions can be steadily incorporated into the surface defects to form inner-sphere complexes. The incorporated heavy metal oxyanions have strong charge–charge and chemical bonding interactions with the surface defect sites, which are much stronger than the hydrogen bonding interactions with the surface OH sites. Moreover, the adsorption affinity of surface defects towards heavy metal oxyanions is stronger than that towards other oxyanions (e.g. SO42− and NO3−), indicating the high adsorption selectivity of heavy metal oxyanions over other oxyanions. Batch adsorption experiments verified that the adsorption of defect-rich Mg(OH)2 adsorbents towards heavy metal ions, e.g., As(V) and Cr(VI), was favorable even under the condition of low concentration (mg L−1 level). These findings reveal the significance of surface defects of Mg(OH)2 for extracting As(V) and Cr(VI) from low-concentration solutions. The proposed strategy of surface defect-fabrication should provide a useful insight into designing effective adsorbents for the selective extraction of heavy metal oxyanions at low concentration.
研究领域:
环境科学
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材料科学
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理论化学
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产品关联
DOI
高影响因子
Journal of Physical Chemistry C
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2015
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IF 4.772
Junwei Yang,Jin Wang,Ke Zhao,Takuya Izuishi,Yan Li,Qing Shen,Xinhua Zhong
Surface trap defects are the limited factor for quantum dots (QDs) application in solar cells. The trapping states can be efficiently suppressed by coating a shell of wider band gap material around the core QDs. We choose CdSe0.65Te0.35 (simplified as CdSeTe) as a model core material, and CdS shell was then overcoated around the CdSeTe core QD to decrease surface defect density and to increase the stability of the core QDs. By optimizing the thickness of the CdS shell, the power conversion efficiency (PCE) of the CdSeTe/CdS quantum dots sensitized solar cells (QDSCs) is enhanced by 13% in comparison with that of plain CdSeTe QDSCs. Transient absorption (TA), incident-photo-to-carrier conversion efficiency (IPCE), open-circuit voltage decay (OVCD), and electrochemical impedance spectroscopy (EIS) measurements confirmed the suppressed charge recombination process in internal QDs and QD/TiO2/electrolyte interfaces with the overcoating of CdS shell around CdSeTe core QDs. With the further overcoating of a-TiO2 and SiO2 barrier layers around the QD-sensitized photoanode, the PCE of champion CdSeTe QDSCs achieved 9.48% (Jsc = 20.82 mA/cm2, Voc = 0.713 V, FF = 0.639) with average PCE 9.39 ± 0.09% under AM 1.5 G one full sun illumination.
研究领域:
材料科学
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能源研究
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DOI
高影响因子
GIANT
·
2023
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IF 7
Yikai Wang,Rui Long,Yang Yang,Daoli Zhang,Jianbing Zhang
Patterned quantum dot color converters (QDCCs) convert blue light to green and red light at the pixel level, thus having potential applications in combination with micro-LED and OLED. Lithography is a promising method to fabricate the QDCCs, however, it is still a challenge to achieve highly luminescent and stable patterned QD-photoresist (PR) thick films. Herein, a strategy is developed to fabricate high-performance patterned QDCCs using the lithography process. Firstly, the QDs are modified by replacing their native hydrophobic ligands to achieve compatibility with PRs. Then, a new ligand, diphenylphosphine oxide (DPPO), is introduced to remedy surface defects of the modified QDs. Lastly, conventional lithography is adopted to fabricate QDCCs with a pattern size of 50 × 10 µm and a thickness of 8 µm. The passivation with DPPO is critical to the luminescent properties of the QD-PR films. The DPPO substantially increases the PLQYs of the PR-compatible QDs and the QD-PR films, achieving a supreme PLQY of 71.7% for the green QD-PR films. The present work might shed light on improving the performance of patterned QDCCs and accelerate their applications in new types of display technology.
研究领域:
材料科学
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显示技术
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产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2023
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IF 5.9
Shuaishuai Liu,Zengming Man,Fan Fang,Pengxin Li,Kun Chang
Surface defect engineering is an effective approach for manipulating the electronic structure for enhancing photocatalytic hydrogen evolution reaction (HER) activities. The surface electronic structure of ZnIn2S4 (ZIS) nanosheets was modified by introducing and regulating surface sulfur vacancies (SV) through Ar-plasma treatment in this work. Optimized ZIS photocatalysts with surface SV deliver a high HER rate of 261.9 μmol·h–1 under visible light (λ > 420 nm), approximately 2.06-fold higher than that of the original ZIS. Significantly, the AQE value reaches 51.2% under 420 nm monochromic light irradiation. A series of characterization analyses prove that SV only exists on the ZIS surface. Furthermore, H2O-FTIR demonstrated that surface SV is more conducive to the adsorption of H2O molecules. Additionally, density functional theory calculations clarify the disparity in the kinetic process of H2 evolution under the alkaline state over ZIS with/without SV. Therefore, Ar-plasma treatment is a beneficial method for regulating the surface SV on ZIS nanosheets, improving the efficiency of the photocatalytic HER.
研究领域:
材料科学
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化学工程
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能源科学
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产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2020
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IF 16.683
Renquan Guan,Dandan Wang,Yujun Zhang,Chen Liu,Wei Xu,Jiaou Wang,Zhao Zhao,Ming Feng,Qingkun Shang,Zaicheng Sun
Photocatalytic N 2 fixation (PNF) provides a low-cost route to generate ammonia. The poor conversion efficiency from photon to ammonia seriously hinders the step forward because of the low concentration of N 2 molecules. Herein, we demonstrate a photocatalyst with surface oxygen vacancies (Vo) and a F modified surface to facilitate N 2 adsorption and activation on the surface of catalysts. The Vo site promotes the chemical adsorption of N 2 , electron transfer from catalyst to N 2 . F modification switches the TiO 2 surface properties from hydrophilic to aerophilic, thus facilitating the adsorption of N 2 . Meanwhile, the hydrogen reduction reaction (HER) is suppressed, as protons hard to adsorb on F capped surfaces. The optimal NH 3 production rate can reach 206 μmolh −1 g −1 , which is ∼ 9 times higher than that of pure TiO 2 nanoparticles (∼23 μmolh −1 g −1 ). This report provides a potential strategy to overcome mass transfer limitation and achieve a high conversion efficiency in PNF.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
Nanoscale
·
2017
·Vol. 9
·期 21
·7252-7259
·
IF 7.367
Longfei Ruan,Wei Shen,Aifei Wang,Qingwen Zhou,Huigang Zhang,Zhengtao Deng
Lead halide perovskites exhibit outstanding optoelectronic and optical properties. However, some applications of perovskites are hindered by their instability in polar environments; thus, how to balance stability with conductivity is a great challenge. Here, we report a new approach of using X-type ligands to address this issue. Surface treatments containing multi-step ligand exchanges and ion filling were necessary to obtain X-type ligand-protected perovskites. Performances of this material show that: (1) the crystal structure of perovskites is stable in ethanol; (2) surface defects can be fixed by a photoactivation process and photoluminescence intensity can be enhanced to 136%; and (3) electronic devices fabricated from such materials show stabilility even after washing with ethanol. X-type ligand-protected perovskites with high stability and good conductivity are promising new materials for wide applications in electronic and optoelectronics devices.
研究领域:
材料科学
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光电材料
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产品关联
DOI
PubMed
高影响因子
ACTA PHYSICO-CHIMICA SINICA
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2014
·Vol. 30
·期 3
·508-512
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IF 0.886
SHENG Jia-Yi,LI Xiao-Jin,XU Yi-Ming
Bi2WO6 is reportedly active for the photocatalytic degradation of organic compounds in aerated aqueous solution, but factors influencing the photocatalytic activity of pristine Bi2WO6 have received little attention. In this study, the effect
of sintering temperature on the physical properties of flower-like Bi2WO6 was investigated. The catalyst was synthesized through the hydrothermal reaction of Na2WO4 and Bi(NO3)3 at 160 for 20 h, followed by sintering in air
at different temperatures for 3 h. Bi2WO6 samples were characterized with X-ray diffraction, scanning electron microscopy, and Raman, ultraviolet-visible diffuse reflectance, and photoluminescence spectroscopies. All samples had similar phase compositions and electronic
structures. Samples exhibited different activities for the photocatalytic degradation of phenol in aerated aqueous solution, under ultraviolet light. With increasing Bi2WO6 sintering temperature, the rate of phenol degradation first increased and then decreased. The maximum
rate of phenol degradation was observed from the catalyst sintered at 350 . Similar results were obtained when the rate of phenol degradation was normalized with the specific surface area of the catalyst, as determined by N2 adsorption. The observed sintering temperature-dependent photoactivity
of Bi2WO6 was attributed to a combination of its crystallinity, light absorption, and surface defects.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2022
·Vol. 106
·期 3
·1766-1777
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IF 4.186
Zehua Wu,Zhixin Zhang,Yong Jia,Fei Teng,Gang Li,Feng Wang,Yuqi Jin
Surface quality of fused silica, particularly surface defect and surface roughness, is a key factor affecting the performance of high-power laser and short-wave optical instrument, and so on. Herein, the super smooth surface of fused silica with roughness of sub-angstrom level and exceedingly few submicron defects was achieved by using ultrafine nano-CeO 2 with primary particle size less than 4 nm, low secondary particle agglomeration strength, and high Ce 3+ concentration. Furthermore, CeO 2 involve in polishing process in the form of primary particle was certified by experiment. Moreover, the cause for the generation of submicron defects on fused silica surface was investigated for the first time from the perspective of secondary particle agglomeration strength of CeO 2 . The concentration of Ce 3+ in CeO 2 was characterized by the redshift of the band-gap energy, and the analysis of material removal rate (MRR) and contact angle of polished fused silica shows that Ce 3+ enhances MRR through increasing the silanol group on fused silica.
研究领域:
材料科学
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光学工程
✓ 已验证
DOI
高影响因子
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