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244 results on '"Zeng, Yicheng"'

59. Colloidal Synthesis and Ultraviolet Luminescence of Rb 2 AgI 3 Nanocrystals.

Author

Deng, Yuan, Zeng, Yicheng, Gu, Wanying, Huang, Pan, Jin, Geyu, Liu, Fangze, Wei, Jing, and Li, Hongbo

Subjects
LUMINESCENCE, SEMICONDUCTOR nanocrystals, BAND gaps, OPTICAL properties, EXCITON theory, NANOCRYSTALS, QUANTUM dots
Abstract

Semiconductor nanocrystals (NCs) hold immense potential as luminescent materials for various optoelectronic applications. While significant progress has been made in developing NCs with outstanding optical properties in the visible range, their counterparts emitting in the ultraviolet (UV) spectrum are less developed. Rb2AgI3 is a promising UV-emitting material due to its large band gap and high stability. However, the optical properties of low-dimensional Rb2AgI3 NCs are yet to be thoroughly explored. Here, we synthesized Rb2AgI3 NCs via a hot injection method and investigated their properties. Remarkably, these NCs exhibit UV luminescence at 302 nm owing to self-trapped excitons. The wide-bandgap nature of Rb2AgI3 NCs, combined with their intrinsic UV luminescence, offers considerable potential for applications in UV photonic nanodevices. Our findings contribute to the understanding of Rb2AgI3 NCs and pave the way for exploiting their unique properties in advanced optoelectronic systems. [ABSTRACT FROM AUTHOR]

Published
2023
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60. Colloidal Synthesis and Optical Properties of Cs 2 CuCl 4 Nanocrystals.

Author

Gu, Wanying, Zeng, Yicheng, Deng, Yuan, Huang, Pan, Jin, Geyu, Liu, Fangze, Wei, Jing, and Li, Hongbo

Subjects
OPTICAL properties, COPPER, PHOTOLUMINESCENCE, NANOCRYSTALS
Abstract

Lead-free copper halide perovskite nanocrystals (NCs) are emerging materials with excellent photoelectric properties. Herein, we present a colloidal synthesis route for orthorhombic Cs2CuCl4 NCs with a well-defined cubic shape and an average diameter of 24 ± 2.1 nm. The Cs2CuCl4 NCs exhibited bright, deep blue photoluminescence, which was attributed to the Cu(II) defects. In addition, passivating the Cs2CuCl4 NCs by Ag+ could effectively improve the photoluminescence quantum yield (PLQY) and environmental stability. [ABSTRACT FROM AUTHOR]

Published
2023
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63. Corrigendum to “Evaluating a commercially available in-duct bipolar ionization device for pollutant removal and potential byproduct formation”[Build. Environ, Volume 195, May 2021, 107750]

Author

Zeng, Yicheng, primary, Manwatkar, Prashik, additional, Laguerre, Aurélie, additional, Beke, Marina, additional, Kang, Insung, additional, Ali, Akram, additional, Farmer, Delphine, additional, Gall, Elliott, additional, Heidarinejad, Mohammad, additional, and Stephens, Brent, additional

Published
2022
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74. Effect of Silver Nanoparticles on the Melting Behavior, Isothermal Crystallization Kinetics and Morphology of Polyoxymethylene

Author

Liu Yongli, Xun Zhang, Minghua Min, Ying Li, Zeng Yicheng, Yang Liu, Qi Guangrui, Wang Lumin, and Huang Hongliang

Subjects
Materials science, General Chemical Engineering, Nucleation, 02 engineering and technology, nucleation sites, 010402 general chemistry, 01 natural sciences, Silver nanoparticle, law.invention, Inorganic Chemistry, symbols.namesake, chemistry.chemical_compound, Reaction rate constant, law, lcsh:QD901-999, General Materials Science, Crystallization, isothermal crystallization kinetics, Arrhenius equation, Polarized light microscopy, POM, Polyoxymethylene, Ag nanoparticles, POM/Ag nanocomposites, 021001 nanoscience & nanotechnology, Condensed Matter Physics, heterogeneous nucleation, Surface energy, 0104 chemical sciences, chemistry, Chemical engineering, symbols, lcsh:Crystallography, 0210 nano-technology
Abstract

In this work, the effects of silver (Ag) nanoparticles on the melting behavior, isothermal crystallization kinetics, and morphology of polyoxymethylene (POM) were studied. It was found that the melting peak temperature (Tm) and the crystallization temperature (TC) of POM/Ag nanocomposites shifted to higher temperature with the content of Ag nanoparticles increased. In addition, the isothermal crystallization kinetics of POM/Ag nanocomposites were determined by Avrami and Lauritzen-Hoffman models. The results of crystallization half-time (t0.5), reciprocal of crystallization half-time (&tau, 0.5), Avrami exponent (n), and Avrami rate constant (k) showed that low loading of Ag nanoparticles (&le, 1 wt%) accelerated the crystallization rate of POM. However, when the content of Ag nanoparticles reached 2 wt%, they aggregated together and restrained crystallization of POM. Meanwhile, the results of nucleation parameter (Kg) and surface free energy of folding (&delta, e) revealed that Ag nanoparticles reduced the energy need to create a new crystal surface, leading to faster crystallization. Moreover, the crystallization activation energies (∆E) were determined using the Arrhenius model, which suggested that Ag nanoparticles induced the heterogeneous nucleation by lowing the ∆E. Furthermore, polarized light microscopy results indicated Ag nanoparticles generated a great amount of nucleation sites and led to the formation of smaller spherulites.

Published
2020
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79. FAPbBr3/Cs4PbBr6 Core/Shell Perovskite Nanocrystals with Enhanced Stability and Emission: Implications for LEDs.

Author

Zeng, Yicheng, Chen, Weiwei, Deng, Yuan, Gu, Wanying, Wu, Chenxi, Guo, Yating, Huang, Pan, Liu, Fangze, and Li, Hongbo

Abstract

Formamidinium lead bromide (FAPbBr3) nanocrystals (NCs) have been demonstrated to exhibit ideal ultrapure green luminescence at 530 nm and to hold great potential in light-emitting diodes, by potentially overcoming the difficulties facing cesium lead bromide (CsPbBr3) NCs. However, compared to all-inorganic lead halide perovskite NCs, organic–inorganic hybrid FAPbBr3 NCs are sensitive to moisture, oxygen, and heat due to their intrinsic instability caused by the organic cations (FA+). Herein, we present an epitaxial growth method for the overgrowth of a large-band-gap cesium lead halide (Cs4PbBr6) shell on the surface of FAPbBr3 NCs. The resulting core/shell NCs show a near-unity photoluminescence quantum yield (PLQY) of 97.1%, the emission with full width at half-maxima of 88 meV, and long-term environmental stability. The introduction of Cs+ into FAPbBr3 NCs can inhibit the migration of FA+ and suppress the phase transformation from cubic phase to tetragonal phase at 60 °C. Furthermore, the existence of shell can provide stronger exciton confinement and improve the thermal stability of FAPbBr3 NCs. The core/shell perovskite NCs developed in this study have the advantages of high PLQY and good stability and may contribute to the field of light-emitting diodes (LEDs). [ABSTRACT FROM AUTHOR]

Published
2022
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88. Effect of Silver Nanoparticles on the Microstructure, Non-Isothermal Crystallization Behavior and Antibacterial Activity of Polyoxymethylene

Author

Ying Li, Hongliang Huang, Xun Zhang, Yongli Liu, Zeng Yicheng, Minghua Min, Yang Liu, and Lumin Wang

Subjects
animal structures, Materials science, Polymers and Plastics, Nanoparticle, Activation energy, Article, Silver nanoparticle, non-isothermal crystallization kinetics, law.invention, lcsh:QD241-441, chemistry.chemical_compound, Differential scanning calorimetry, lcsh:Organic chemistry, antibacterial activity, law, Monolayer, Crystallization, POM, Nanocomposite, Ag nanoparticles, Polyoxymethylene, POM/Ag nanocomposites, General Chemistry, chemistry, Chemical engineering, heterogeneous nuclei, sense organs
Abstract

Silver (Ag) nanoparticles were synthesized by a facile route in the presence of oleic acid and n-propylamine. It was shown that the average primary size of the as-synthesized Ag nanoparticles was approximately 10 nm and the surface of as-synthesized Ag nanoparticles was capped with monolayer surfactants with the content of 19.6%. Based on as-synthesized Ag nanoparticles, polyoxymethylene (POM)/Ag nanocomposites were prepared. The influence of Ag nanoparticles on non-isothermal crystallization behavior of POM was investigated by differential scanning calorimetry (DSC). The Jeziorny, Jeziorny-modified Avrami, Ozawa, Liu and Mo, Ziabicki and Kissinger models were applied to analyze the non-isothermal melt crystallization data of POM/Ag nanocomposites. Results of half time (t1/2), crystallization rate parameter (CRP), crystallization rate function (K(T)), kinetic parameter (F(T)), the kinetic crystallizability at unit cooling rate (GZ) and the crystallization activation energy (∆E) were determined. Small amounts of Ag nanoparticles dispersed into POM matrix were shown to act as heterogeneous nuclei, which could enhance the crystallization rate of POM, increase the number of POM spherulites and reduce POM spherulites size. However, the higher loading of Ag nanoparticles were easily aggregated, which restrained POM crystallization to some degree. Furthermore, the POM/Ag nanocomposites showed robust antibacterial activity against Escherichia coli and Staphylococcus aureus.

Published
2020
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95. Contributors

Author

Alimi, Mohsen, Azar, Ahmad Taher, Bansal, Nishtha, Benamrouche, Nacereddine, Benyahia, Nabil, Berrahal, Chaker, Bisht, Aman, Denoun, Hakim, Drhorhi, Ismail, Duy, Vo Hoang, El Fadili, Abderrahim, El Magri, Abdelmounime, Fekik, Arezki, Giri, Fouad, Gundara, Gugun, Hamida, Mohamed Lamine, Hidayat, Yuyun, Kalhor, Ahmad, Kamal, Nashwa Ahmad, Kumar, Vineet, Lajouad, Rachid, Mathpal, Sandhya, Mohamed, Mohamad Afendee, Paluri, Sruti, Pham, Viet-Thanh, Rana, K.P.S., Rebai, Abdelwaheb, Rhif, Ahmed, Salimi Lafmejani, Amir, Sambas, Aceng, Serrano, Fernando E., Singh, Shikha, Sukono, Tale Masouleh, Mehdi, Vaidyanathan, Sundarapandian, Yasuda, Gen'ichi, Zaouia, Mustapha, Zeng, Yicheng, and Zhang, Sen

Published
2021
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98. An Adaptive Denoising Algorithm for Chaotic Signals Based on Improved Empirical Mode Decomposition.

Author

Wang, Mengjiao, Zhou, Zequan, Li, Zhijun, and Zeng, Yicheng

Subjects
HILBERT-Huang transform, THRESHOLDING algorithms, ALGORITHMS, SIGNAL denoising, CHAOS theory
Abstract

It is difficult to determine the threshold of mode cell in the interval-thresholding algorithm, when it is used to denoise chaotic signals. In this paper, an adaptive denoising algorithm is proposed for chaotic signals based on improved empirical mode decomposition. First, the noisy chaotic signal is decomposed into the intrinsic mode functions (IMFs) by improved complete ensemble empirical mode decomposition. Then, the zero-crossing scale thresholding denoising algorithm is used to denoise the IMFs with different thresholds. The optimal threshold is obtained by the Durbin–Watson criterion. With the optimal threshold, the final denoised chaotic signal is obtained. The proposed algorithm effectively solves the issue mentioned above. The experimental results show the proposed algorithm can denoise noisy chaotic signals in different conditions effectively and is better than other existing algorithms. [ABSTRACT FROM AUTHOR]

Published
2019
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