Journal of Physical Chemistry Letters
·
2024
·
IF 4.8
Hongyan Yin,Can Zhang,Quanzhen Zhang,Pu Wang,Jianguo Tang,Sui Mao
Metallic nanoparticles can generate photoexcited hot carriers on the femtosecond scale under light excitation, which holds immense significance for applications such as optical communication and ultrafast imaging. In this study, a tunnelling junction structure with ZrO2 as the dielectric layer is designed and fabricated to achieve efficient hot hole collection between Au nanoparticles and P-type Si. Through characterizations of photoconductive atomic force microscopy, the electrical transition from an ohmic contact to a tunneling junction is confirmed, and the transfer pathway of Au hot holes to P-type Si upon 520 nm excitation is clearly observed. The impact of the tunneling structure on device performance is investigated through the fabrication of Si/ZrO2/Au/TiO2 photodiodes. The performance tests show that hot hole collection by the tunneling effect significantly enhances a range of parameters, e.g., external quantum efficiency by 250%. Noticeably, the external quantum efficiency attributed to photogenerated hot carriers under 520 nm excitation is estimated to exceed 2.5%. Moreover, the transient photoresponse of the photodiodes is examined with a typical rising time of less than 20 ns.
研究领域:
光电子学
·
纳米光子学
·
固态物理
·
材料科学
·
半导体器件
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry Letters
·
2022
·
IF 6.888
Yonggang Yang,Zhinan Jiang,Yang Liu,Tiantian Guan,Qi Zhang,Chaochao Qin,Kai Jiang,Yufang Liu
Real-time monitoring of singlet–triplet transitions is an effective tool for studying room-temperature phosphorescent molecules. For femtosecond transient absorption (TA) spectroscopy of a 2,6-di(9H-carbazol-9-yl) pyridine molecule in dimethyl sulfoxide (DMSO), the stimulated emission signal (380 nm) and the excited-state absorption signal (650 nm) reach their maximum intensity within 397 fs. Subsequently, the two signals decay with time and the triplet–triplet absorption (TTA) signal (400 nm) is enhanced synchronously, accompanied by an isosbestic point at 491 nm. These results confirm intersystem crossing (ISC) within 2.5 ns. Moreover, the TTA signal (400 nm) in nanosecond TA spectroscopy gradually disappeared, accompanied by a phosphorescence lifetime of 4.1 μs. As the solvent polarity decreases (DMSO > N,N-dimethylformamide > 1,4-dioxane > toluene), similar spectral dynamic processes are observed, while the durations of ISC processes and phosphorescence lifetimes are shortened. This combined femtosecond and nanosecond transient absorption spectroscopy study presents the ultrafast excited-state dynamics of organic phosphorescent molecules.
研究领域:
物理化学
·
光谱学
·
材料科学
·
有机电子学
·
光物理
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Yang Mi,Anqiang Jiang,Lei Kong,Jun Wang,Heng Guo,Sheng-Nian Luo
I–III–VI ternary quantum dots (QDs) have emerged as favorable alternatives to the toxic II–VI QDs for optoelectronic and biological applications. However, their use as optical gain media for microlasers is still limited by a low fluorescence efficiency. Here, we demonstrate amplified spontaneous emission (ASE) and lasing from colloidal QDs of Zn-processed AgIn5S8 (AIS) for the first time. The passivation treatment on the AIS QDs yields a 3.4-fold enhancement of fluorescence quantum efficiency and a 30% increase in the two-photon absorption cross section. ASE is achieved from the AIS/ZnS core/shell QD films under both one- and two-photon pumping with a threshold fluence of ∼84.5 μJ/cm2 and 3.1 mJ/cm2, respectively. These thresholds are comparable to the best optical gain performance of Cd based-QDs reported in the literature. Moreover, we demonstrate a facile whispering-gallery-mode microlaser of the core/shell QDs with a lasing threshold of ∼233 μJ/cm2. The passivated AIS QDs can be promising optical gain media for photonic applications.
研究领域:
量子点
·
光电子学
·
光子学
·
材料科学
·
纳米技术
·
激光物理
✓ 已验证
DOI
高影响因子
Journal of Analysis and Testing
·
2018
·Vol. 2
·期 4
·332-341
·
IF 0
Wei Yin Hui,Li Xin Yu,Gao Jie,Liu Jia Jun,Yuan Dan,Yin Bin Cheng,Wang Jian
As an antibiotic, tetracycline has been widely used against bacterial infection or as feed additives for growth promotion, which may lead to the enrichment of antibiotic residues in animals or their products. Therefore, the detection of tetracycline is closely related to human health. The morphological transformation of CoOOH nanoflakes induced by tetracycline was monitored by scanning electron microscope images, dark-field light scattering images and optical spectra, which found that tetracycline could decompose CoOOH nanoflakes into small nanoparticles with low light scattering signal. As a result, the reduced light scattering of CoOOH nanoflakes was proportional to the increased concentration of tetracycline in the range of 1.0–250 μmol/L, and the limit of determination (LOD) was 0.23 μmol/L (3σ/k). Most foreign substances did not interfere in the analysis of tetracycline. Furthermore, the concentration of tetracycline in different milk samples detected with the standard addition method was so low that it accorded with the safety regulation, which was similar to the detection result with high-performance liquid chromatography (HPLC).
研究领域:
分析化学
·
纳米技术
·
食品安全
·
药物分析
✓ 已验证
产品关联
DOI
JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Tao Tang,Chengcai Li,Wenyu He,Wei Hong,Hailin Zhu,Guojin Liu,Yuan Yu,Caihong Lei
In this paper, the ZIF-8/ZnO mixture was sintered at high temperature to prepare C-ZnO composite nano-particles with excellent photocatalytic degradation ability under ultraviolet light , and then blended with PVDF to fabricate PVDF composite membrane with capabilities of photocatalytic degradation of methylene blue(MB) via solution phase conversion. The results show that the photocatalytic performance of the prepared C-ZnO composite particles was the best when the ZIF-8/ZnO mass ratio was 1:2, and the photocatalytic degradation efficiency of the PVDF composite film prepared was as high as 95.02% when the composite particle content was 15%. The photocatalytic activity of C-ZnO composite material benefits from the synergy between the two. Moreover, the efficiency of photodegradation of MB remained above 90% after the composite membrane was subjected to five cycles of experiments, which solved the problem that the traditional photocatalyst was difficult to recycle. In addition, it is found that O 2 - plays a major role in the photocatalytic degradation of MB through free radical capture experiments. All in all, the PVDF composite membrane containing C-ZnO composite particles has a foreseeable potential in the field of photocatalytic printing and dyeing wastewater in the future.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2014
·
IF 2.354
Ni Cheng,Xiaoyuan Ma,Xiang Sheng,Tao Wang,Rui Wang,Jingjing Jiao,Li Yu
Two structurally similar imidazolium-based anionic surface active ionic liquids (SAILs) with double hydrocarbon chains, viz. 1-butyl-3-methylimidazolium bis(2-ethylhexyl) sulfosuccinate (C 4 mim-AOT) and 1-butyl-3-methylimidazolium bis(2-ethylhexyl) phosphate (C 4 mim-DEHP), were synthesized by a straightforward ion-exchange technique. A comparative investigation of their aggregation behavior with the corresponding traditional anionic surfactants, sodium bis(2-ethylhexyl) sulfosuccinate (Na-AOT) and sodium bis(2-ethylhexyl) phosphate (Na-DEHP) in aqueous solution was performed in detail by surface tension, electric conductivity, fluorescence spectra and dynamic light scattering measurements. The critical micelle concentration (CMC) values for the surfactants with double hydrocarbon chains obtained by different techniques are in good agreement. The surface activity of C 4 mim-AOT and C 4 mim-DEHP is superior to that of the corresponding traditional anionic surfactants, Na-AOT and Na-DEHP. It is also found that for anionic SAILs the nature of the anionic active group is a dominant factor in the determination of their aggregation behavior in aqueous solution, e.g. CMC and aggregation number, while the introduced organic cation plays a minor role. Theoretical calculations show that more conformations and electronegativity for DEHP anion leads to higher aggregation number and CMC values for C 4 mim-DEHP. This work is expected to be of practical values for the environmental friendly anion SAILs in nanomaterial synthesis and phase separation, etc.
研究领域:
物理化学
·
胶体与界面化学
·
纳米材料合成
·
环境友好材料
·
分子自组装
✓ 已验证
DOI
高影响因子
Materials Horizons
·
2017
·Vol. 4
·期 2
·274-280
·
IF 10.706
Ke Zhang,Mingzeng Peng,Wei Wu,Junmeng Guo,Guoyun Gao,Yudong Liu,Jinzong Kou,Rongmei Wen,Ying Lei,Aifang Yu,Yang Zhang,Junyi Zhai,Zhong Lin Wang
Flexible functional devices based on two dimensional (2D) materials are extremely suitable for malleable, portable and sustainable applications, such as health monitoring, electronic skin and optoelectronics. In this work, we developed a flexible photodetector based on a p-CuO/n-MoS2 heterojunction with an enhancement in photocurrent and detection sensitivity. Because of the non-centrosymmetric structure in monolayer MoS2, the piezo-potential induced by applied strain adjusts the band structure at the heterojunction interface and broadens the depletion region based on the piezo-phototronic effect. The border depletion can be discreetly used to improve the photo-generated carrier separation and transport to enhance photoresponse performance. When illuminated by a 532 nm laser, the photocurrent of the heterojunction can be enhanced 27 times under a tensile strain of 0.65% compared to strain free conditions and the detection sensitivity can reach up to 3.27 × 108 Jones. As a result, our research provides a new strategy for novel design and performance optimization of 2D material heterostructures in the application of optoelectronics.
研究领域:
材料科学
·
纳米科技
·
光电子学
·
凝聚态物理
·
功能器件
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2015
·
IF 7.435
Wanjun Wang,Xingqiu Chen,Gang Liu,Zhurui Shen,Dehua Xia,Po Keung Wong,Jimmy C. Yu
A new visible-light-driven photocatalyst , monoclinic dibismuth tetraoxide (m-Bi 2 O 4 ), has been discovered. This simple oxide with mixed valent states (Bi 3+ and Bi 5+ ) has a band gap energy of 2.0 eV, and is responsive to wavelength up to 620 nm. The first-principle calculations within the hybrid density functional framework (HSE) indicate that m-Bi 2 O 4 is a typical indirect-gap semiconductor. It shows much higher photocatalytic degradation activity as well as photostability than some of the well-investigated highly efficient photocatalysts, such as CdS and Bi 2 O 3 . Not only typical dyes and colorless aromatic compounds, including rhodamine B, methyl orange, methyl blue, phenol and 4-nitrophenol, but also bacterial ( Escherichia coli ) cells can be effectively degraded/inactivated in the presence of m-Bi 2 O 4 . The electronic potential of band structure is studied and a photocatalytic mechanism is also proposed, in which both OH and direct h + oxidation play important roles in the degradation process. Our discovery highlights the potential of developing Bi 2 O 4 -based photocatalysts as a new class of highly active, stable and safe photocatalyst for versatile pollutant degradation and disinfection under visible light .
研究领域:
材料科学
·
环境科学
·
光催化
·
半导体物理
·
污染治理
·
应用化学
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2022
·Vol. 51
·期 17
·6908-6917
·
IF 4.569
Xuexia Chen,Ran Pang,Shangwei Wang,Jiangyue Su,Weihong Yuan,Shengjian Jiao,Haiyan Wu,Da Li,Chengyu Li,Hongjie Zhang
Bi3+ has gained increasing attention due to its abundant reserves, adjustable luminous colour and high chemical stability, therefore, Bi3+-activated luminescent materials have already been extensively applied in various fields. Herein, a novel blue-emitting CaNaSb2O6F:Bi3+ (CNSOF:Bi3+) phosphor with a pyrochlore-type structure with the space group Fdm (277) was successfully synthesized. It exhibits a broad absorption band in the n-UV region (290–390 nm) and an ideal blue emission band centered at 441 nm. Interestingly, the wide emission peak of CNSOF:Bi3+ shows strongly temperature-dependent fluorescence properties and good thermal degradation resistance in the cycle temperature range from 298 K to 473 K, and the relative sensitivity is calculated to reach the maximum value of 2.34% K−1 at 423 K. Besides, the phosphor is different from a traditional optical temperature sensing material which shows the emission peak of trivalent rare earth ions. The wide emission peak makes the instrument insensitive to the peak shift, which dramatically reduces the requirement of the instrument, and the emission peak does not shift with the temperature to enhance the measurement stability, thus saving the cost. These results indicate that the CNSOF:Bi3+ blue emitting phosphor has potential applications in temperature sensing.
研究领域:
材料科学
·
无机化学
·
光电子学
·
功能材料
·
传感器技术
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2022
·Vol. 51
·期 18
·7333-7342
·
IF 4.569
Hua Yu,Liuyan Zhou,Renguang Ye,Degang Deng,Shiqing Xu
Polychromatic emission can be achieved by controlling the distribution of the rare earth activator in multi-cation lattices, which can be used in the fields of white light LED and fluorescence temperature sensing. However, it is still a challenge to control their distribution and location of the target site in a given host material because the distribution of the rare earth activator is uncertain. In this paper, we have chosen Li4SrCa(SiO4)2 as the multi-cation site host and induced the distribution of Eu2+ ions between different cation sites through anion substitution, for the first time, to regulate the luminescence characteristics of a series of Li4SrCaSi2O8−yN2y/3:Eu2+ phosphors. In Li4SrCa(SiO4)2:Eu2+ phosphors, the substitution of O2− by N3− triggered a distinct ordered to disordered structure transition of the SiO4 tetrahedron and induced the remote distribution of the Eu2+ activator, which was verified through the analysis of the XRD, EPR, FT-IR and fluorescence spectra. Due to the location of Eu2+ ions in different cation sites (Eu2+Sr and Eu2+Ca), two distinguishable emission peaks with tunable color emissions and different responses to temperature were realized. The white LED that utilized blue-orange-emitting Li4SrCaSi2O4N8/3:Eu2+ and green-emitting BaSi2O2N2:Eu2+ (500 nm) displayed an outstanding color rendering index (Ra) of 85.1. Based on the fluorescence intensity ratio (FIR) technique, an optical temperature measurement mechanism was hypothesized and studied in the temperature range of 293–473 K. The highest Sa of the material was 0.086 K−1, and Sr was 1.76% K−1 based on the FIR detection technology, revealing obviously better than most inorganic optical temperature-measuring materials reported before. Our work indicates that Li4SrCaSi2O8−2yN4y/3:Eu2+ is a promising material for application in White LEDs and optical thermometers.
研究领域:
材料科学
·
发光材料
·
无机化学
·
光电子学
·
传感器技术
✓ 已验证
DOI
高影响因子
NANO
·
2024
·
IF 1
Zhenqian Zhang,Yixing Li,Xinyue Yu,Bijun Fang
The rare-earth ion doping in nanocrystals has the advantage on improving the interested properties. As one of rare-earths, the trivalent samarium ion (Sm 3 + ) was used as a dopant. The precursor of Sm 3 + -doped cadmium ferrite (CdFe 2 O 4 ) nanocrystals was reacted in water-soluble polymeric nanoreactors as a dispersed phase in miniemulsion, and then calcinated to form doped nanocrystals. The 1% Sm 3 + -doped nanocrystal in small size exhibited the smaller narrow gap energy and weak photoluminescent emission intensity; which attributed to the positive influences on the photocatalytic degradation. The selected Sm 3 + -doped spinel ferrite nanocrystals provide a unique catalyzer for organic compound photodegradation.
研究领域:
材料科学
·
纳米技术
·
无机化学
·
环境科学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2019
·
IF 3.131
Xiaotong Sun,Luting Yan,Runxiang Xu,Mingyuan Xu,Yanyun Zhu
TiO 2 presents a broad application prospect in the field of degradation of environmental pollutants. However, the development of TiO 2 photocatalyst has been limited by two factors, namely, narrow spectral response range and low quantum efficiency . Surface coating can selectively change the physical and chemical properties of core particles, whereas the synergistic action between core and shell can optimize material performance. In this paper, surface modification of titanium dioxide (TiO 2 ) by dopamine polymerization was used to improve its photocatalytic performance. Among polydopamine (PDA)-modified TiO 2 , TiO 2 @PDA-0.4 mg/mL-2 h showed the best degradation rate of Rhodamine B (RhB): the degradation rate reached 99.28% and 77.40% after 1.5 h of ultraviolet–visible (UV–vis) and visible (Vis) light irradiation, respectively. Compared with the uncoated TiO 2 , the degradation rate has shown improvement, especially under Vis light irradiation, with the photocatalytic performance improving by 35.04%. Absorption, emission, and impedance spectra showed that surface modification of TiO 2 with suitable thickness of PDA effectively increased light absorption and promoted separation of photogenerated carriers . High-performance liquid chromatography–mass spectrometry revealed the differences in photocatalytic degradation mechanism of TiO 2 @PDA to RhB under UV–vis and Vis light irradiation. Compared with those under UV–vis light irradiation, the intermediate products under Vis light irradiation are relatively simple. TiO 2 @PDA generated more electrons, which interacted with H 2 O to produce large amounts of ·OH and holes under UV–vis light irradiation in comparison with that under Vis light irradiation. In addition to deacetylation , deamination , and decarboxylation by hydroxylation , excess ·OH in the photocatalytic process would attack benzene rings directly to produce N , N -diethylacetamide.
研究领域:
材料科学
·
环境化学
·
光催化
·
纳米材料
·
表面工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）