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254 results on '"Qi, Zhengjian"'

57. Perovskite Light‐Emitting Diodes with EQE Exceeding 28% through a Synergetic Dual‐Additive Strategy for Defect Passivation and Nanostructure Regulation

Author

Liu, Zhe, primary, Qiu, Weidong, additional, Peng, Xiaomei, additional, Sun, Guanwei, additional, Liu, Xinyan, additional, Liu, Denghui, additional, Li, Zhenchao, additional, He, Fangru, additional, Shen, Chenyang, additional, Gu, Qing, additional, Ma, Fulong, additional, Yip, Hin‐Lap, additional, Hou, Lintao, additional, Qi, Zhengjian, additional, and Su, Shi‐Jian, additional

Published
2021
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59. Crystallographic and magnetic properties of nanocrystalline perovskite structure SmFeO 3 orthoferrite

Author

Qi Li, Ashwini Kumar, Huihui Zhao, Jingdong Shen, and Qi Zhengjian

Subjects
Orthoferrite, Materials science, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Nanocrystalline material, Inorganic Chemistry, Condensed Matter::Materials Science, Magnetization, Crystallography, chemistry.chemical_compound, Magnetic anisotropy, Ferromagnetism, chemistry, 0103 physical sciences, Materials Chemistry, Antiferromagnetism, Condensed Matter::Strongly Correlated Electrons, Orthorhombic crystal system, 010306 general physics, 0210 nano-technology, Powder diffraction
Abstract

In this article, we present the structural and magnetic studies of pristine SmFeO3 nanocrystalline ceramic samples as sintered at temperature 850 °C and 1000 °C. X-ray powder diffraction data confirm the existence of single-phase nature with orthorhombic (Pbnm) structure of the samples. The SEM image reveals spherical particles with a size range of 60–130 nm for SFO-850 and SFO-1000 samples. X-ray absorption spectroscopy studies on Fe L3,2 and O K-edges of SmFeO3 sample revealed the homo-valence state of Fe in these materials. From magnetization studies it has been observed the materials exhibit ferromagnetic and antiferromagnetic (canted spin structure) sub-lattices, which results strong magnetic anisotropy in the system.

Published
2018

71. Defect passivation with novel silicone copolymers for efficient perovskite light-emitting diodes.

Author

He, Fangru, Liu, Zhe, Qing, Jian, Zhao, Xinxin, Liu, Xinyan, Ma, Fulong, Dai, Yanpeng, Su, Shi-Jian, Hou, Lintao, and Qi, Zhengjian

Subjects
LIGHT emitting diodes, PEROVSKITE, PASSIVATION, COPOLYMERS, QUANTUM efficiency, POLYETHYLENE glycol
Abstract

Pinhole-free perovskite films with low defect density are essential to boost the efficiency of metal halide perovskite light-emitting diodes (PeLEDs). In this work, a novel amphiphilic silicone copolymer (Si14-PEG14-QAC) is introduced into perovskite as a passivation agent to improve the performance of PeLEDs. Si14-PEG14-QAC possesses polyethylene glycol and –NCH3 units, which can interact with perovskite by hydrogen bonding, resulting in high-quality perovskite films with small-size crystals, high coverage, low defect density, and enhanced photoluminescence quantum yield. Consequently, the perovskite films with Si14-PEG14-QAC enable efficient green PeLEDs with an external quantum efficiency of 4.5%, which is much higher than that of the control device without the polymer passivator (0.86%). This work suggests the great potential of silicone copolymers as passivation agents for high-quality perovskite films with high performance. [ABSTRACT FROM AUTHOR]

Published
2021
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75. Light‐Enhanced Tandem‐Responsive Nano Delivery Platform for Amplified Anti‐tumor Efficiency.

Author

Wang, Xing, Li, Yuanhang, and Qi, Zhengjian

Subjects
*TREATMENT effectiveness, *PHOTODYNAMIC therapy, *REACTIVE oxygen species, *ENDOPLASMIC reticulum, *CANCER treatment
Abstract

Designing nanomedicines with low toxicity, high targeting, excellent therapeutic effects, and precise release is always the major challenges in clinical cancer treatment. Here, we report a light‐enhanced tandem‐responsive nano delivery platform COF‐B@X‐03 for amplified anti‐tumor efficiency. Biotin‐loaded COF‐B@X‐03 could precisely target tumor cells, and the azo and hydrazone bonds in it would be depolymerized by the overexpressed azoreductase and acidic microenvironment in hypoxic tumors. In vitro experimental results indicate mitochondrial and endoplasmic reticulum stress caused by COF‐B@X‐03 under light is the direct cause of tumor cell death. In vivo experimental data prove COF‐B@X‐03 achieves low oxygen dependent phototherapy, and the maintenance of intratumoral hypoxia provides the possibility for the continuous degradation of COF‐B@X‐03 to generate more reactive oxygen species for tumor photodynamic therapy by released X‐03. In the end, COF‐B@X‐03 phototherapy group achieves higher tumor inhibition rate than X‐03 phototherapy group, which is 81.37 %. Meanwhile, COF‐B@X‐03 significantly eliminates the risk of tumor metastasis. In summary, the construction of this tandem‐responsive nano delivery platform provides a new direction for achieving efficient removal of solid tumors in clinical practice. [ABSTRACT FROM AUTHOR]

Published
2024
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76. Synthesis, characterization, and optical properties of a novel alternating 3-dodecyloxythiophene-co-pyridine copolymer

Author

Qi Zhengjian, He Yanfang, Wang Xue-mei, Wei Bin, Sun Yueming, and Yu Jing

Subjects
chemistry.chemical_classification, Materials science, Photoluminescence, Polymers and Plastics, General Chemistry, Polymer, Conjugated system, Condensed Matter Physics, Photochemistry, Gel permeation chromatography, chemistry.chemical_compound, chemistry, Pyridine, Polymer chemistry, Materials Chemistry, Copolymer, Proton NMR, Cyclic voltammetry
Abstract

A novel soluble alternating conjugated copolymer, comprised of 3-dodecyloxythiophene and pyridine moieties, was synthesized via the Heck Couple approach. Regioregular poly(3-dodecyloxythiophenel) synthesized by McCullough was also studied for comparison. The obtained polymers were characterized by 1H NMR, HR-MS, gel permeation chromatography, UV–Vis spectroscopy, photoluminescence and Cyclic voltammetry. The photoluminescence of the copolymer exhibited extraordinary bright blue. The electrochemical study shows that the new alternating copolymer does not merely have the properties of the two units that constitute it but has mutual hole and electron charge carrier properties which might be promising material for applications in high efficiency, single or low number layers functional devices.

Published
2008

82. Synthesis, Characterization of a Novel Light Stable Cross-Linker—Isophorone Diisocyanate Terpolymer Composite

Author

Luo Zhen-yang, Sun Yueming, Qi Zhengjian, and Li Xiangxin

Subjects
chemistry.chemical_classification, Materials science, Polymers and Plastics, General Chemical Engineering, Materials Science (miscellaneous), Trimer, Self-condensation, Isocyanate, chemistry.chemical_compound, Alicyclic compound, Monomer, chemistry, Polymer chemistry, Materials Chemistry, Reactivity (chemistry), Isophorone diisocyanate, Fourier transform infrared spectroscopy
Abstract

Isophorone diisocyanate (IPDI) is an alicyclic isocyanate, in which the outcomes always possess good light and heat stability. A novel IPDI terpolymer composite were synthesized and characterized using Fourier transform infrared (FTIR), Nuclear magnetic resonance (NMR), gas permeation chromatography (GPC), and the chemical analysis method. The result showed that IPDI terpolymer composite could be prepared in the presence of Cat-5 catalyst and under the reaction temperature between 70 ∼ 90°C. The colorless or pale yellow liquid products without solvent could be obtained in a short time under optimized reaction conditions. In addition, the IPDI trimer/monomer mixture having an NCO content ranging from 25.0% to 28.0% and average nominal functionality of from 2.5 to 2.8 could be compatible with sufficient reactivity and liquidity.

Published
2006

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