查找使用阿拉丁产品的科研文献

Self-Powered UV Photodetector of TiO2 with BaTiO3 Surface Modification and Light-Controlled Logic Circuits Application

Zhen Wang,Jianping Xu,Shaobo Shi,Jing Chen,Jianghua Xu,Lina Kong,Xiaosong Zhang,Lan Li,Shougen Yin

One-dimensional (1D) metal oxides with excellent carrier transport and light absorption properties can be applied to photodetectors (PDs), facilitating device miniaturization, portability, and integration. Surface modification of 1D semiconductors can reduce carrier recombination in PDs as a way to increase photocurrent and decrease dark current of PDs. Herein, ultrathin BaTiO3 (BTO) shell layers are grown on the surface of TiO2 nanorod arrays (NRs) by in situ conversion using hydrothermal reaction, and the self-powered TiO2-BTO NRs PDs are constructed. The effect of the thickness of BTO shell layers on the photoresponse characteristics of self-powered TiO2-BTO NRs PDs is investigated by controlling the Ba2+ conversion concentration. The results show that the BTO shell layer reduces the dark current of the PDs because of the decreased interfacial transfer resistance and improved transfer of photogenerated carriers for building a “bridge” of carrier transport between BTO and TiO2 due to the formation of Ti–O–Ti bonds. Moreover, the presence of the spontaneous polarization electric field in BTO enhances the photocurrent and response speed of PDs. The self-powered TiO2-BTO NRs PDs are integrated in series and parallel to realize the functions of “and” and “or” gates of light-controlled logic gates. The ability to convert light signals into electrical signals for the self-powered PDs in real time demonstrates its great potential for optoelectronic interconnection circuits, which has important application prospects in the field of optical communication.

Rapid Light Response of a Novel Bi-Based Metal–Organic Framework for Bacterial Wound Infections Treatment

Lihua Wu,Yue Luo,Hu Wei,Shuilin Wu,Yufeng Zheng,Zhaoyang Li,Zhenduo Cui,Yanqin Liang,Shengli Zhu,Jie Shen,Xiangmei Liu

Bismuth metal–organic frameworks (MOFs) as catalysts are scarce. Herein, the first MOF comprising meso- tetra(4-carboxyphenyl) porphine (TCPP) as an organic ligand and Bi ion as a metal node, denoted as Bi-TCPP, is synthesized by a convenient one-step hydrothermal method. Compared to other 2D (Cu-TCPP) or 3D (PCN-222) MOFs with TCPP as a ligand, Bi-TCPP has ultrafast singlet oxygen generation ability and a high photothermal conversion efficiency of 49.5% under the irradiation of 660 nm light. This is due to Bi-TCPP's strong ligand-to-metal charge transfer (LMCT) events that form singlet oxygen ( 1 O 2 ). Further, when the electrons and holes above the bandgap relax to the band edge, the excess energy is converted into heat. In vitro and in vivo experiments show excellent antibacterial and repair effects. Hence, the synthesis of Bi-TCPP provides new ideas for the study of rare bismuth-based MOFs, and its excellent biocompatibility provides a possibility for further application.

Thermally stable near-infrared emission from a double perovskite K2LiScF6:Cr3+ phosphor for light-emitting diodes

Tao Yang,Lingxiang Chu,Ting Zhang,Qiang Zhou,Yi Qin,Zhengliang Wang,Jing Wan,Mingmei Wu

The exploration of Cr 3+ -doped near-infrared (NIR) phosphors for light-emitting diodes has attracted widespread attention. In this work, we present a fluoride double perovskite K 2 LiScF 6 :Cr 3+ NIR-emitting phosphor through a co-precipitation method. It was found that the Cr 3+ activators undergo a weak crystal field and present a NIR emission band peaking at 768 nm under blue light excitation (430 nm). Meanwhile, the K 2 LiScF 6 :Cr 3+ exhibits a high activation energy (0.537 eV), a weak electron-phonon coupling (EPC) effect and a remarkable photoluminescence thermal stability at 423 K, with an intensity of 95.1% of that at room temperature. Profiting from the luminescent properties, clear night vision images and human palm vein photographs were realized by coating the K 2 LiScF 6 :Cr 3+ phosphor on a blue InGaN chip and using it as a lighting source, suggesting its applicability in light-emitting diodes for NIR spectroscopy applications.

Oxygen-modified graphitic carbon nitride with nitrogen-defect for metal-free visible light photocatalytic H2O2 evolution

Yanqing Cong,Shiyi Zhang,Qiuang Zheng,Xinyue Li,Yi Zhang,Shi-Wen Lv

Photocatalytic oxygen reduction is regarded as the cleanest approach for the production of hydrogen peroxide (H 2 O 2 ). Herein, oxygen-modified graphite carbon nitride (g-C 3 N 4 ) with nitrogen-defect (namely g-C 3 N 4 -ND4-OM3) was synthesized by a feasible method. Owing to the existence of nitrogen vacancy and oxygen-containing functional group, the absorption bands derived from n → π* and π → π* electronic transitions were enhanced, thereby enlarging the visible light response range of catalysts. Interestingly, nitrogen-defect can capture electron and effectively suppress the recombination of photoinduced electrons and holes. More importantly, the introduction of oxygen-containing functional groups can improve the hydrophilicity of g-C 3 N 4 , which was beneficial for the adsorption of dissolved oxygen. The electrostatic potential distributions of g-C 3 N 4 -based photocatalyst structural unit were also changed after introducing nitrogen vacancy and oxygen-containing functional group, and the electron-donating ability of g-C 3 N 4 was improved. As a result, the evolution rate of H 2 O 2 catalyzed by g-C 3 N 4 -ND4-OM3 was as high as 146.96 μmol/g/L under visible light irradiation. The photocatalytic H 2 O 2 generation was completed through the direct 2-e − oxygen reduction. In short, current work will share novel insights into photocatalytic H 2 O 2 generation over g-C 3 N 4 -based catalyst.

Catalyst-free and visible light-induced RAFT alternating polymerization of 1,3-pentadiene isomers and maleic anhydride

Kun Liu,Qiaoqiao Xiong,Zhuowei Gu,Feng Zhang,Yawen Fu,Fengli Xie,Wenjun Yi,An Li,Jundong Xu,Lijun Li

Visible light-mediated photoinduced reversible addition-fragmentation chain transfer polymerization (RAFT) copolymerization of 1,3-pentadiene isomers and maleic anhydride (MAH) in the absence of photocatalysts or photoinitiators was realized in tetrahydrofuran (THF) solvent at r.t. under various visible wavelengths. The well-defined alternating copolymers were successfully and efficiently synthesized by directly using O -ethyl- S -benzoic thioanhydride ( EBT ) as chain transfer agent activated by blue light (460 nm). The conventional thermal-initiated radical copolymerization of 1,3-pentadiene (PD) isomers (except cis -1,3-pentadiene (CP)) and MAH gave both DA cycloaddition products and alternating sequence copolymers. In contrast, the alternating copolymer was the only isolated product in this photoinitiated polymerization system, in which the DA reaction was completely suppressed. Moreover, both trans -1,3-pentadiene (TP) and PD isomers can be copolymerized with MAH to give alternating copolymers with high yields up to 100%, although the photopolymerization rates are in the order: PD > CP > TP. And the copolymerization can be implemented by simply switching the light source ON/OFF. We supposed that the donor–acceptor interaction between the PD and MAH (similar to St (styrene)/MAH system) plays an important role in this novel light-induced RAFT alternating copolymerization behavior.

980 nm Near-Infrared Light-Emitting Diode Using All-Inorganic Perovskite Nanocrystals Doped with Ytterbium Ions

Zhenglan Ye,Taoran Liu,Dan Chen,Yazhou Yang,Jiayi Li,Yaqing Pang,Xiangquan Liu,Yuhua Zuo,Jun Zheng,Zhi Liu,Buwen Cheng

Visible-light mediated synthesis of main-chain-type semifluorinated alternating terpolymers by NaI catalyzed START polymerization

Chaojie Li,Jiannan Cheng,Yi Zhang,Qing Yu,Zhiru Yuan,Weiwei He,Xiaoguang Bao,Lifen Zhang,Zhenping Cheng

Fluorinated polymers are a class of fascinating materials due to their unique features; however, they have not been applied widely in daily life because of the restricted synthetic methodology and limited availability of various monomers. In this work, main-chain-type semifluorinated alternating terpolymers (SFATs) (AB1)n-co-(AB2)m are prepared by a step transfer-addition and radical-termination (START) polymerization strategy using NaI as the catalyst under irradiation with visible light at room temperature. Herein, 1,6-diiodoperfluorohexane and two α,ω-unconjugated dienes with different structures are used as A, B1 and B2 monomers, respectively. Interestingly, a dual alternating polymerization process can be possible at the beginning of terpolymerization by using dienes with flexible and rigid chains as B1 and B2, respectively. In addition, compared to binary copolymers (AB)n previously synthesized by START polymerization, facile regulation of Tg of the SFATs can be achieved easily either by adjusting the feed ratio of two B monomers or by the removal of the periodic iodine atoms formed in SFATs. Overall, this work provides a guide for the synthesis of a broad range of fluorinated polymers by increasing participating monomers, allowing easier adjustment of the chemical composition and facilitating the integration of desirable properties into fluoropolymers to fulfill diverse requirements in practical application.

High-Density Ultrafine Au Nanocluster-Doped Co-LDH Nanocages for Enhanced Visible-Light-Driven CO2 Reduction

Mei Li,Zhenyang Zuo,Shengbo Zhang

Developing effective photocatalysts for CO2 reduction to high value-added chemicals or fuels is a promising strategy for alleviating serious environmental problems and energy crisis. Currently, the photocatalytic efficiency is still too slow to arouse industrial interest for most semiconductor photocatalysts due to their low CO2 uptake, limited visible light capture capacity, and serious recombination of electron–hole. Herein, we successfully synthesized a high-density ultrafine Au cluster (∼0.7 nm)-doped cobalt-layered double hydroxide nanocage (Au/Co-LDH) photocatalyst through an in situ redox strategy to explore the structure–activity relationship in the CO2 reduction system. A series of experimental characterizations showed that CO2 adsorption, visible light capture capacity, and charge transfer rate are significantly enhanced due to the highly dispersed and ultrafine Au cluster doping. Density functional theory calculations indicate that Au doping also promoted charge redistribution at the active site, increased the density of states near the Fermi energy level, stabilized the *COOH intermediate, and reduced the energy barrier of the rate-determining step. As a result, Au/Co-LDH delivers a CO evolution rate of 5610 μmol g–1 h–1 toward CO2 reduction under visible light (λ > 420 nm), which is 4 times and 22 times more active than the undoped one and Au nanoparticles, respectively. We believe that this work will provide an important implication for the development and optimization of photocatalysts for CO2 reduction.

Large-Scale Synthesis of Tunable Fluorescent Carbon Dots Powder for Light-Emitting Diodes and Fingerprint Identification

Lei Zhao,Dong Zhang,Xin Wang,Yang Li,Zihan Li,Hua Wei,Boxuan Yao,Gongtao Ding,Zifan Wang

The emergence and fast development of carbon dots (CDs) provide an unprecedented opportunity for applications in the field of photoelectricity, but their practicability still suffers from complicated synthesis procedures and the substrate dependence of solid-state fluorescence. In this study, we design a unique microwave-assisted solid-phase synthesis route for preparing tunable fluorescent CD powders with yellow, orange, and red fluorescence (Y-CDs, O-CDs, R-CDs) by simply adjusting the mass ratio of reactants, a method which is suitable for the large-scale synthesis of CDs. The Y-/O-/R-CDs were systematically characterized using physics and spectroscopy techniques. Based on the perfect solid-state fluorescence performance of the proposed fluorescent CD powders, the Y-/O-/R-CDs were successfully applied for the construction of multi-color and white light-emitting diode devices at low cost. Furthermore, the Y-CDs displayed much higher yield and luminous efficiency than the O-CDs and R-CDs and were further used for fingerprint identification on the surfaces of glass sheets and tinfoil. In addition, the R-CD aqueous solution fluorescence is sensitive to pH, suggesting its use as a pH indicator for monitoring intracellular pH fluctuations. The proposed series of fluorescent powders composed of CDs may herald a new era in the application of optical components and criminal investigation fields.Keywords:tunable carbon dots;large-scale synthesis;solid-phase synthesis;light-emitting diodes;fingerprint identification

Structure investigation of light-colored lignin extracted by Lewis acid-based deep eutectic solvent from softwood

Jiayi Zheng,Liheng Chen,Xueqing Qiu,Yingchun Liu,Yanlin Qin

Lignin is the most abundant natural phenolic polymer. However, the severe condensations of industrial lignin resulted in an undesirable apparent morphology and darker color, which hindered its application in the field of daily chemicals. Therefore, a ternary deep eutectic solvent is used to obtain lignin with light-color and low condensations from softwood. The results showed that the brightness value of lignin extracted from aluminum chloride-1,4-butanediol-choline chloride at 100 °C and 1.0 h was 77.9, and the lignin yield was 32.2 ± 0.6%. It is important that 95.8% of β-O-4 linkages (β-O-4 and β-O-4′) was retained. Lignin is used to prepare sunscreens and is added to physical sunscreens at 5%, with SPF up to 26.95 ± 4.20. Meanwhile, enzyme hydrolysis experiments and reaction liquid composition tests were also conducted. In conclusion, a systematic understanding of this efficient process could facilitate high-value utilization of lignocellulosic biomass in industrial processes.

Fabricating 3D Moisture- and NIR Light-Responsive Actuators by a One-Step Gradient Stress-Relaxation Process

Ling Hu,Jinqiang Jiang,Zhao-Tie Liu,Zhong-Wen Liu,Guo Li

Polymeric materials that can actuate under the stimulation of environmental signals have attracted considerable attention in fields including artificial muscles, soft robotics, implantable devices, etc. To date, the improvement of shape-changing flexibility is mainly limited by their unchangeable shapes and structural and compositional distributions. In this work, we report a one-step treatment process to convert 2D poly(ethylene oxide)/sodium alginate/tannic acid thin films into 3D-shaped moisture- and NIR light-responsive actuators. Spatial surface wetting of the film leads to the release of residual stress generated in film formation in a gradient manner, which drives the wetted regions to bidirectionally bend. By controlling the position and bending amplitude of the wetted regions, designated 3D shapes can be obtained. Moreover, Fe3+ ions in the aqueous solution used for surface wetting can coordinate with carboxylate groups in sodium alginate chains to form a gradient cross-linking network. This gradient network can not only stabilize the resulting 3D shape but also render the film with moisture-responsive morphing behaviors. Fe3+ ions can also self-assemble with tannic acid molecules to form photothermal aggregates, making the film responsive to NIR light. We further show that films with versatile 3D shapes and different modes of deformation can be fabricated by a one-step treatment process. This strategy is convenient and extendable to develop 3D-shaped polymer actuators with flexible shape-changing behaviors.

Light-Colored Maillard Peptides: Formation from Reduced Fluorescent Precursors of Browning and Enhancement of Saltiness Perception

Yanqun Zhang,Yishun Yao,Tong Zhou,Foxin Zhang,Xue Xia,Jingyang Yu,Shiqing Song,Khizar Hayat,Xiaoming Zhang,Chi-Tang Ho

The browning formation and taste enhancement of peptides derived from soybean, peanut, and corn were studied in the light-colored Maillard reaction compared with the deep-colored reaction. The fluorescent compounds, as the browning precursors, were accumulated during the early Maillard reaction of peptides and subsequently degraded into dark substances, which resulted in a higher browning degree of deep-colored Maillard peptides (MPs), especially for the MPs derived from corn peptide. However, the addition of l-cysteine in light-colored Maillard reaction reduced the formation of deoxyosones and short-chain reactive α-dicarbonyls, thereby weakening the generation of fluorescent compounds and inhibited the browning of MPs. Synchronously, the peptides were thermally degraded into small peptides and amino acids, which were consumed less during light-colored thermal reaction due to its shorter reaction time at high temperature compared with deep-colored ones, thus contributing to a stronger saltiness perception of light-colored MPs than deep-colored MPs. Besides, the Maillard reaction products derived from soybean and peanut peptides possessed an obvious “kokumi” taste, making them suitable for enhancing the soup flavors.