PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
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2011
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IF 1.304
Huirui Zhou,Ke Tao,Yunqi Sui,Kang Sun
The heterogeneous nucleation and growth of CdSe domains on the Fe 3 O 4 seed nanocrystals are hard to be controlled because of significant lattice mismatch between Fe 3 O 4 and CdSe nanocrystals. Current study exploits the choice of surface ligand and crystal morphology for Fe 3 O 4 seed to investigate ways to overcome the energy barrier imposed by the lattice mismatch for the promotion and control of subsequent growth of CdSe nanocrystals on seeded crystals. Results indicate that the growth of CdSe domains on seed nanocrystals not only depends on the affinity of ligands toward seed nanocrystals, but also is affected by the seed ligands in a similar way to synthesizing individual second-domain nanocrystals. Furthermore, preferential growth of CdSe domains on the corner of cubic seeds are observed, and cubic Fe 3 O 4 nanocrystals are favored for the heterogeneous nucleation of CdSe as opposed to spherical ones. A three-stage growth model (heterostructures formation, the adsorption of Se and the heterogeneous nucleation and growth) is proposed, where choice of ligands, geometry features, such as surface curvature and defects are found to have significant impact to overcome energy barrier from lattice mismatch.
研究领域:
材料科学
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纳米技术
✓ 已验证
DOI
高影响因子
ACS Applied Nano Materials
·
2023
·
IF 5.9
Hao Hao,Hui-Ling Hu,Yi Liu,Feng-Lei Jiang
In this work, CdSe/ZnS core/shell quantum dots (QDs) were synthesized. Dilution of the as-synthesized QDs would lead to instability with photoluminescence (PL) quenching. It was found that the addition of tertiary phosphine and alkylthiol could recover the PL intensity of diluted QDs and make these QDs stable. Specifically, the recovery efficiency of tertiary phosphine was stronger than that of alkylthiol. Trioctylphosphine (TOP) and octanethiol (OT) were chosen as the representative ligands, respectively. Isothermal titration calorimetry (ITC) demonstrated that interactions between both TOP/OT and QDs were exothermic and spontaneous. The interaction between TOP and QDs was mainly driven by van der Waals forces due to the branched structure. This interaction had a negative entropy change, while the interaction between OT and QDs had a positive entropy change. There were about ∼12 TOP molecules and ∼17 OT molecules bound to a QD particle. The binding constants of TOP/OT to QDs were 1.6 × 103 and 12.8 × 103 M–1, respectively. The reaction rate between TOP and QDs was fast, and the addition of OT could slow the reaction rate constant from 0.081 to 0.024 min–1. PL decay indicated that TOP and OT could increase the radiative recombination of excitons. Furthermore, both TOP and OT could greatly improve the brightness of the QD films, which was a prerequisite for the efficient improvement of quantum dot light-emitting diodes. This work explicitly investigated the dilution process of QDs, explored the methods for keeping diluted QDs stable and bright, and highlighted the importance of surface ligands.
研究领域:
材料科学
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光学
✓ 已验证
DOI
高影响因子
MICROCHIMICA ACTA
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2020
·Vol. 187
·期 10
·1-9
·
IF 6.232
Jiao Mingxia,Li Yun,Jia Yuxiu,Xu Le,Xu Guiyun,Guo Yingshu,Luo Xiliang
Water-soluble Cu nanoclusters (NCs) with tunable emission were synthesized through an eco-friendly one-pot aqueous method. Blue-, green-, and red-emitting NCs with the emission peaks at 420 nm, 505 nm, and 630 nm were obtained by employing ethanediamine, cysteine, and glutathione as surface ligands, respectively. The ligand effects on the optical properties of Cu NCs were studied by the single variable method. It has been revealed by systematic characterizations that the dependence of emission color on the structures of ligands was mainly attributed to their different size-tuning effects. Glutathione has the strongest chelating ability and it can significantly reduce the monomer reactivity and thus decrease the supersaturation degree of the reaction, which is favorable for modulating Cu precursor to grow into larger NCs. In contrast, ethanediamine ligand resulted in smaller nanoclusters due to its weaker binding capability. Because of the strong emission and terrific fluorescent stability, Cu NCs capped with ethanediamine, possessing an emission peak at 420 nm when excited at a wavelength of 350 nm, were directly used for probing Hg(II) with satisfying selectivity, presenting a linear range of 0.1–5.0 mM and a detection limit of 33 μM. The sensor showed good performance in real sample analysis with recoveries ranging from 99% to 103%, and comparable accuracy with atomic fluorescence spectroscopy, manifesting the reliability of the current strategy for sensing Hg(II).
Water-soluble copper nanoclusters with blue, green, and red emissions were synthesized by employing ethanediamine, cysteine, and glutathione as surface ligands respectively, and the blue-emitting nanoclusters with strong emission and terrific stability were directly used for selectively sensing Hg 2+ .
研究领域:
材料科学
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分析化学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
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2020
·
IF 8.758
Shaomin Peng,Zuoliang Wen,Taikang Ye,Xiangtian Xiao,Kaiyang Wang,Junmin Xia,Jiayun Sun,Tianqi Zhang,Guanding Mei,Haochen Liu,Bing Xu,Xiaojun Li,Rui Chen,Guichuan Xing,Kai Wang,Zikang Tang
Metal-halide perovskite-based green and red light-emitting diodes (LEDs) have witnessed a rapid development because of their facile synthesis and processability; however, the blue-band emission is constrained by their unstable chemical properties and poorly conducting emitting layers. Here, we show a trioctylphosphine oxide (TOPO)-mediated one-step approach to realize bright deep-blue luminescent FAPbBr3 nanoplatelets (NPLs) with enhanced stability and charge transport. The concentration of NPL surface ligands is shown to be progressively tuned via varying the amount of intermediate TOPO due to the acid–base equilibrium between protic acid and TOPO. By effectively optimizing the concentration of surface ligands, the structural integrity of NPL solids can be preserved in ambient air for a week, mainly because of the highly ordered and dense solid assembly and the reduced defects. The removal of excess organic ligands also enables the improvement of charge mobility by orders of magnitude. Ultimately, ultrapure deep-blue perovskite LEDs (439 nm) with a narrow emission width of 14 nm and a peak EQE of 0.14% are achieved at low driving voltage. Our finding expands the current understanding of surface ligand modulation in the development of pure bromide deep-blue perovskite optoelectronics.
研究领域:
材料科学
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光电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Materials Today Chemistry
·
2024
·
IF 6.7
Tingting Xu,Yingwei Li,Zhezhen Wei,Shuai Liu,Jianan Sun,Rongchao Jin,Yongbo Song
Assembly of nanoparticles (NPs) is of crucial importance for the construction of functional materials and devices. Although tremendous progress has been made in constructing various types of superlattices, it is still difficult to elucidate the assembly mechanism at the molecular/atomic level, because the surface ligands and interactions cannot be seen by electron microscopy. To tackle this, we adopt an atomically precise nanochemistry approach and demonstrate with oblate [Au 31 Cu 32 (SPh t Bu) 34 (P(SC 4 H 3 ) 3 ) 8 ] + nanoclusters (NCs) which can self-assemble into both template-free spherical superstructures upon fast evaporation and single crystals via slow non-solvent diffusion. The size of the assembled solid nanospheres (∼300 nm) can be controlled by the amount of n -hexane (non-solvent) added to the Au 31 Cu 32 solution. On the other hand, adding a second solvent of lower vapor pressure leads to hollow nanospheres (∼380 nm) instead of solid ones. These self-assembly processes are reversible. By contrast, single crystals can be grown by slowly diffusing n -hexane into the Au 31 Cu 32 solution, and subsequent X-ray analysis reveals the details of ligand interactions, that is, each oblate Au 31 Cu 32 coordinates with the closest ones via two types of ligand interactions: (1) between the thiolates along the polar axis, and (2) between the phosphines in the equatorial plane. This indicates that anisotropic van der Waals forces can drive the formation of template-free nanospheres of Au 31 Cu 32 NCs. The results from this work also sheds light on the superstructure formation for conventional NPs.
研究领域:
纳米科学
·
材料化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2023
·
IF 3.7
Hao Wu,Xiaoyu Cheng,Songjun Xie,Yan Huang,Raheel Ahmed Janjua,Xinzi Liu,Sailing He
Aluminum quantum dots (AlQDs) are an emerging class of optical material due to their unique photoluminescence in the ultraviolet waveband. Herein, a strategy is presented to control their photoluminescence emission. The synthesized AlQDs displayed photoluminescence from the UV-B region (<320 nm) to the near-ultraviolet region (∼425 nm) and high quantum yields. Our investigation revealed that surfactants and phosphonic acids (PAs) were competitively bound to the surface of AlQDs, and this was affected by the space volume of surfactants and charge of head groups. The steady-state and time-resolved spectroscopic data suggested the emission properties of AlQDs mainly originated from the surface-mediated states. The red-shifting of emission peak was a result of increased amount of PAs on the surface of AlQDs, which could be related to the surface oxygen presented in both ligands and surfactants. Overall, this study indicates a method to control the photoluminescence of AlQDs by changing the surfactants and surface ligands, which is fundamental to their applications in photonics and applications to energy and environment, in addition to biomedicine.
研究领域:
材料科学
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光学
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能源与环境科学
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生物医学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
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2019
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IF 4.309
Weizheng Wang,Yumeng Zhang,Wenhui Wu,Xiaoyu Liu,Xuanxuan Ma,Guixiang Qian,Jiyang Fan
The organic–inorganic hybrid metal halide perovskites with different dimensions and diverse architectures are highly attractive materials for optoelectronic applications. However, people know little about the dynamics of their formation processes. Here, we study both experimentally and theoretically the self-assembly formation dynamics of the luminescent colloidal CH3NH3PbBr3 nanocrystals. We have observed their successive transformations from original spherical quantum dots to periodically stacked nanoplatelets when the primitive colloidal nanocrystals with a high concentration were maintained in liquid for a prolonged period of time. A theoretical dynamic collision model by taking into account the popular van der Waals force, the polarization force that is unique for the perovskites, and the electrostatic forces between particle surfaces in the presence of the surface ligands is proposed to explain the self-assembly process of the colloidal CH3NH3PbBr3 nanocrystals. The result reveals that the rather easy self-assembly of the organic–inorganic hybrid perovskites with different morphologies in the absence of enough surface ligands is closely related to their intrinsic polarization force, whereas the presence of the surface ligands could hamper the self-assembly process. The proposed theoretical model is general and can be used to analyze the self-assembly dynamics of various types of colloidal nanostructures.
研究领域:
材料科学
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光学
·
化学动力学
✓ 已验证
DOI
高影响因子
ACS Applied Nano Materials
·
2025
·
IF 5.5
Zheng Wen,Fangzhou Yi,Guanlin Ke,Zhenhua Sun
This study investigates near-infrared (IR) phototransistors utilizing hybrid systems of indium gallium zinc oxide (IGZO) and PbSe colloidal quantum dots with distinct surface ligands and diameters. Tetrabutylammonium iodine (TBAI)-modified quantum dot film exhibits an insulative property and abundant traps. Under 1064 nm light illumination, the devices with TBAI-modified quantum dots achieve a high photoresponsivity of 2.63 × 104 A/W, a high detectivity of 1.15 × 1014 Jones, and an exceptional photosensitivity exceeding 107 in transient response. In contrast, the mercaptopropionic acid (MPA)-modified quantum dot film shows higher conductivity and fewer traps, resulting in faster relaxation of photon-induced carriers and a rapid response speed of the devices with MPA-modified quantum dots. Additionally, the device with MPA-modified quantum dots exhibits better air stability compared to the TBAI-modified device. The impact of quantum dot size on device performance was explored, revealing that the device based on larger PbSe quantum dots exhibits superior performance under 1550 nm illumination, with the photoresponsivity and detectivity reaching 4.96 × 105 A/W and 2.88 × 1015 Jones, respectively. This research provides valuable insights and suggests promising applications for IGZO-PbSe quantum dot hybrid systems in the development of high-performance near-IR photodetectors with customizable properties.
研究领域:
材料科学
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光电探测器
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纳米技术
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICA CHIMICA ACTA
·
2019
·
IF 5.256
Xiaoli Luo,Xin Xie,Yingcai Meng,Taoli Sun,Jinsong Ding,Wenhu Zhou
Aluminum is a very important analyte, and developing biosensors for aluminum is an important analytical task. In this work, we report a novel mechanism to design colorimetric sensor based on gold nanoparticles (AuNPs). The AuNPs were prepared by reducing HAuCl 4 using catechols , and the resulting AuNPs can be directly adapted for Al 3+ detection without any post-modifications, showing high sensitivity and selectivity against other metal ions . Interestingly, our mechanistic studies revealed that Al 3+ -induced AuNPs aggregation was not due to the formation of interparticle crosslinks that refers to the design principle of most AuNPs-based colorimetric sensors reported before. But rather, Al 3+ competitively coordinated with the capping ligands on AuNPs surface through the formation of stable Al–O bond, which dissociated these ligands from AuNPs surface. As a result, the AuNPs aggregated due to the loss of surface stabilizers. Based on this mechanism, several catechols, including pyrocatechol (PC), 3-(3,4-dihydroxyphenyl) propionic acid (DHCA), levodopa (LDA) and dopamine (DA), were used as reductant to prepare AuNPs for Al 3+ sensing, and the AuNPs prepared by DA (AuNPs/DA) displayed the highest sensitivity, with detection limit of 0.81 μM. The sensor was then tested for Al content analysis in river water and food samples, and the results supported its practical applications. Importantly, this work expands the design principles for colorimetric sensors by using AuNPs.
研究领域:
分析化学
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纳米技术
·
环境科学
✓ 已验证
DOI
PubMed
高影响因子
LANGMUIR
·
2020
·
IF 3.557
Qiujun Lu,Hu Dong,Jiali Hu,Linna Huang,Youyu Zhang,Mingxia Li,Meiling Liu,Yaqian Li,Cuiyan Wu,Haitao Li
Germanium quantum dots (GeQDs) show unique advantages in fluorescence applications due to their large quantum confinement effect and excellent biocompatibility. However, GeQDs are confronted with difficulty in accurately controlling the fluorescence emission. This defect brings challenges to understanding the fluorescence mechanism and limits the potential applications of GeQDs. In this paper, a series of GeQDs with the average diameter of about 2.6 nm modified with different ligands were synthesized by the chemical reduction method. The fluorescence emission of GeQDs can be changed from blue to yellow-green through adjusting the surface ligands. The influence of surface ligands on the fluorescence emission of GeQDs was thoroughly investigated by experimental and theoretical calculations. Furthermore, the synthesized GeQDs exhibit good biocompatibility and photostability and can act as high-performance fluorescence probes for long-term fluorescent bioimaging. This work provides a good and deep understanding of the fluorescence mechanism of GeQDs and will facilitate diverse promising applications of GeQDs in the near future.
研究领域:
材料科学
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生物学
·
医学影像
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2019
·
IF 6.393
Shuqin Yang,Zhilong Song,Naibo Gao,Zhixiang Hu,Licheng Zhou,Jingyao Liu,Baohui Zhang,Guangzu Zhang,Shenglin Jiang,Hua-Yao Li,Huan Liu
Indium oxide (In 2 O 3 ) nanomaterials have been investigated extensively as promising candidates for gas sensor applications. Here, we fabricate near room temperature operable H 2 S-sensitive gas sensors based on In 2 O 3 colloidal quantum dots (CQDs). Room-temperature film deposition of In 2 O 3 CQDs followed by surface ligand exchange treatment through Cu inorganic salts was employed to construct the sensor devices. Combined with a moderate annealing treatment, the long-chain ligands surrounding the quantum dot surfaces were completely removed to enhance gas adsorption and carrier transport, simultaneously resulting in the formation of CuO that may act as a catalytic promoter or form p-n heterojunction for selective H 2 S detection. The sensors exhibited high response up to 90 toward 5 ppm of H 2 S with response/recovery time of 72 s/200 s respectively, suggestive of a performance improvement compared to the In 2 O 3 -based H 2 S sensors reported in existing literature. The power law analysis indicated that the main oxygen species adsorbed on the surfaces were O 2 − and O − with the proportion of approximate 1:1 at near room temperature. The gas-sensing mechanism was attributed to the decisive role of surface states in determining the electrical conduction of quantum dot gas sensors.
研究领域:
材料科学
·
传感器技术
·
纳米科技
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2022
·Vol. 28
·期 64
·e202201682
·
IF 5.02
Longbin Xian,Nanlin Zhang,Zufu Luo,Xiaolin Zhang,Chonglin Yuan,Xiuting Li
Graphical Cyclic voltammetry (CV) is employed to determine the band edges and trap states of ZnO QDs with different surface ligands. It is demonstrated that the ZnO QDs without surface ligands mainly have oxygen interstitial defects whilst the ZnO QDs covered with ligands contain oxygen vacancies. The electronic structure of quantum dots (QDs) including band edges and possible trap states is an important physical property for optoelectronic applications. The reliable determination of the energy levels of QDs remains a big challenge. Herein we employ cyclic voltammetry (CV) to determine the energy levels of three types of ZnO QDs with different surface ligands. Coupled with spectroscopic techniques, it is found that the onset potential of the first reductive wave is likely related to the conduction band edges while the first oxidative wave originates from the trap states. The determined specific energy levels in CV further demonstrates that the ZnO QDs without surface ligands mainly have oxygen interstitial defects whilst the ZnO QDs covered with ligands contain oxygen vacancies. The present electrochemical method offers a powerful and effective way to determine the energy levels of wide bandgap ZnO QDs, which will boost their device performance.
研究领域:
材料科学
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电化学
·
半导体物理
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）