Nanomaterials
·
2020
·Vol. 10
·期 3
·464
·
IF 4.324
Sizhe Hu,Kai Jiang,Yuci Wang,Sui Wang,Zhongjun Li,Hengwei Lin
Carbon dots (CDs) with a room temperature phosphorescent (RTP) feature have attracted considerable interest in recent years due to their fundamental importance and promising applications. However, the reported matrix-free RTP CDs only show short-wavelength (green to yellow) emissions and have to be triggered by ultraviolet (UV) light (below 400 nm), limiting their applications in certain fields. Herein, visible-light-excited matrix-free RTP CDs (named AA-CDs) with a long-wavelength (orange) emission are reported for the first time. The AA-CDs can be facilely prepared via a microwave heating treatment of L-aspartic acid (AA) in the presence of ammonia and they emit unique orange RTP in the solid state with visible light (420 nm) excitation just being switched off. Through the studies of the carbonization process, the C=O and C=N containing moieties in the AA-CDs are confirmed to be responsible for the observed RTP emission. Finally, the applications of AA-CDs in information encryption and anti-counterfeiting were preliminarily demonstrated.Keywords:carbon dots;room temperature phosphorescence;visible-light-excitation;anti-counterfeiting
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 13
·2210
·
IF 5.719
Huiyong Wang,Hongmei Yu,Ayman AL-Zubi,Xiuhui Zhu,Guochao Nie,Shaoyan Wang,Wei Chen
The synthesis of room temperature phosphorescent carbon dots (RTP-CDs) without any matrix is important in various applications. In particular, RTP-CDs with dual modes of excitation are more interesting. Here, we successfully synthesized matrix-free carbonized polymer dots (CPDs) that can generate green RTP under visible and ultraviolet light dual-mode excitation. Using acrylic acid (AA) and ammonium oxalate as precursors, a simple one-pot hydrothermal method was selected to prepare AA-CPDs. Here, acrylic acid is easy to polymerize under high temperature and high pressure, which makes AA-CPDs form a dense cross-linked internal structure. Ammonium oxalate as a nitrogen source can form amino groups during the reaction, which reacts with a large number of pendant carboxyl groups on the polymer chains to further form a cross-linked structure. The carboxyl and amino groups on the surface of AA-CPDs are connected by intermolecular hydrogen bonds. These hydrogen bonds can provide space protection (isolation of oxygen) around the AA-CPDs phosphor, which can stably excite the triplet state. This self-matrix structure effectively inhibits the non-radiative transition by blocking the intramolecular motion of CPDs. Under the excitation of WLED and 365 nm ultraviolet light, AA-CPDs exhibit the phosphorescence emission at 464 nm and 476 nm, respectively. The naked-eye observation exceeds 5 s and 10 s, respectively, and the average lifetime at 365 nm excitation wavelength is as long as 412.03 ms. In addition, it successfully proved the potential application of AA-CPDs in image anti-counterfeiting.Keywords:carbon dots;room temperature phosphorescence;visible/ultraviolet light excitation;anti-counterfeiting
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CEMENT & CONCRETE COMPOSITES
·
2025
·
IF 13.1
Jihong Jiang,Yanchun Miao,Qianping Ran,Yali Li,Yunjian Li,Zongshuo Tao,Zeyu Lu
Fly ash, a by-product of coal combustion, is a pozzolanic solid waste with annual production of 1.63 billion tonnes, which has been widely used to replace cement clinker to develop sustainable concrete. However, the incorporation of high volumes of inert fly ash significantly reduces the early mechanical strength of concrete due to its low pozzolanic activity. This study presents an innovative strategy to effectively enhance the reactivity of fly ash by utilizing hydroxyl free radicals (•OH), highly reactive oxidative species generated by nano-TiO 2 under UV light excitation. Experimental results demonstrated that photoexcited nano-TiO 2 significantly promoted the depolymerization of inert glassy phases in fly ash, resulting in a 28 % increase in Ca(OH) 2 consumption within 72 h. Consequently, the compressive and flexural strengths of mortar at 28 days increased by 37 % and 16 %, respectively, with a strength activity index reaching 95.4 %. In addition, the water absorption and chloride ion diffusion coefficient were reduced by 15 % and 18 %, respectively, due to a more refined pore structure driven by enhanced pozzolanic reactivity. Density Functional Theory (DFT) calculations further revealed that •OH substantially lowered the energy barrier for Si-O-Al bonds cleavage (from 22.93 kcal/mol for OH − to 8.54 kcal/mol for •OH), confirming its superior catalytic efficiency and thermodynamic advantage. In conclusion, the findings confirm that photoexcited nano-TiO 2 can serve as an effective activator for enhancing the utilization efficiency of fly ash in sustainable concrete.
研究领域:
建筑材料学
·
可持续发展工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL PHYSICS
·
2024
·Vol. 160
·期 24
·
IF 3.1
Wang Ye,Wang Dongdong,Hu Xiao,Zhang Song
The ultrafast proton transfer and the following dynamics for aromatic Schiff bases N , N ′-bis(salicylidene)ethylenediamine (salen) and N , N ′-bis(salicylidene)-1,4-butylenediamine (salbn) were investigated with experimental and theoretical methods. A dual emission property with a large Stokes shift in salen and salbn indicates that excited state intramolecular proton transfer occurs with photoexcitation. An efficient single proton transfer was confirmed within 200 fs for both molecules. Subsequently, a fast twisted motion of the keto moiety carries cis -keto to a relaxed stable geometry in the S 1 state. Following the twisted motion, the phenol ring at keto moiety further rotates to a conical intersection with the ground state and a cis – trans isomerization occurs. The isomerization rate is high, which dominates the competition with the radiative transition, resulting in weak emission intensity. It is confirmed that the length of alkyl chain affects the direction of phenol ring twisting and rotation during the whole subsequent relaxation of excited cis -keto tautomer. Compared with polar solvent acetonitrile, the barrier of isomerization is higher and the hydrogen bond on keto moiety is stronger in nonpolar solvent toluene. It makes fluorescence radiation channels competing with isomerism more likely to occur, contributing to the observed difference of enol/keto emission ratios of salen and salbn in toluene and acetonitrile.
研究领域:
物理化学
·
理论化学
·
光化学
✓ 已验证
DOI
高影响因子
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2024
·Vol. 130
·期 6
·1-10
·
IF 2.5
He Yu,Li Xin,Guo Yangyang,Mao Huibing,Chen Ye,Wang Jiqing
The ZnS: Ho 3+ , Yb 3+ , Mn 2+ nanomaterials fabricated by the co-precipitation method have the zinc-blende structure with the crystallite size about 90 ∼ 100 nm. The X-ray diffraction (XRD), the scanning electron microscope (SEM) and the transmission electron microscope (TEM) characterizations confirm that the doping of the Mn 2+ has less effect on the structure of the ZnS: Ho 3+ , Yb 3+ , Mn 2+ nanomaterials. With the excitation of a 978 nm laser, the upconversion (UC) emissions of the ZnS: Ho 3+ , Yb 3+ , Mn 2+ nanomaterials include two emission bands located at 551 and 664 nm, which correspond to the transitions 5 F 4 ( 5 S 2 )→ 5 I 8 and 5 F 5 → 5 I 8 of the Ho 3+ ions. The UC emission characterization confirms that the UC emission of the ZnS: Ho 3+ , Yb 3+ nanomaterials can be modulated by the doping of the Mn 2+ ions, the increase of the incident laser power and the change of the laser pulse-width. The red emission of the ZnS: Ho 3+ , Yb 3+ nanomaterials particle will increase significantly with the incorporation of the Mn 2+ ions. The incident laser power and the laser pulse-width also can modulate the intensity ratio G / R of the green to the red. With the increase of the incident laser power, the emission intensity ratio G / R will also increase. With the increase of laser pulse-width from 0.2 to 0.8 ms, the above intensity ratio G/R will decrease significantly. The modulation between the green and red emission is due to the energy transfer from the 5 F 4 ( 5 S 2 ) state to the 5 F 5 state of the Ho 3+ ions through the state 4 T 1 of the Mn 2+ ions.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Chemistry
·
2024
·
IF 6.7
Hanyu Xu,Yanling Wei,Rong Wang,Guiying Liang,Tianqi Sheng,Zuoling Fu
The cesium-based fluoride Cs 3 YF 6 has increasingly attracted curiosity due to its potential in up-conversion luminescence applications, signifying a possible revolutionary change in the next generation of lanthanide-doped luminescent functional materials. However, the nature of the photoluminescence process involving Cs 3 YF 6 has still not been studied in detail. Developing Cs 3 YF 6 luminescence applications is an intricate endeavor. Herein, we present the optimal doping concentration required for Eu 3+ and Tb 3+ doping in Cs 3 YF 6 . Meanwhile, by spectra analyses and theoretical model simulations, we have been able to decipher the intricacies of the energy transfer interaction that transpires between Tb 3+ and Eu 3+ ions. Furthermore, a water-sensitive fluorescence response system tailored for anti-counterfeiting applications was designed, which relied on the superior luminescence characteristics of Cs 3 YF 6 doped with Tb 3+ /Eu 3+ under excitation at 254 nm, whilst simultaneously exploiting the easily deliquescent nature of Cs 3 YF 6 . This work not only enhances the understanding of Cs 3 YF 6 materials in the field of rare-earth luminescence but also introduces a novel anti-counterfeiting strategy, that propels the development of applications for rare-earth-doped fluoride materials.
研究领域:
材料科学
·
光学
·
稀土发光材料
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2023
·
IF 3.7
Yong Yang,Shenman Yao,Wufei Gong,Yan Liang,Ting Yu,Cailei Yuan
Light excitation has been developed as an economical way to realize room-temperature gas sensing recently. However, the high recombination rate of photogenerated carriers in semiconductor gas sensing materials leads to very limited carriers that can effectively take part in sensing reactions, which greatly restricts the further performance improvement of gas sensing under light excitation. Here, a hierarchical Z-scheme heterostructure microsphere of MoS2/SnO2 is designed and prepared. The heterostructure demonstrates an outstanding NO2 sensing performance at room temperature with the excitation of a low-power LED light (0.06 W), which exhibits an ultrahigh sensitivity of 264.2 to 10 ppm of NO2 along with acceptable response/recovery properties. The physical mechanism of NO2 sensing is analyzed. The results suggest that the construction of the Z-scheme heterostructure between MoS2 and SnO2 can greatly promote the separation of photogenerated carriers so that more photogenerated carriers can take part in the NO2 sensing reaction. Furthermore, the designing of a hierarchically porous structure can provide abundant active sites for gas sensing reactions. The work not only expands the development of Z-scheme heterostructures in gas sensing but also provides a strategy to promote the performance of light-excited gas sensors by designing a Z-scheme heterostructure with a hierarchically porous structure.
研究领域:
材料科学
·
传感器技术
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Leyao Bi,Boyan Fu,Jiahui Lin,Junsheng Wen,Jiaxing Fu,Binglin Zou,Ningning Su,Chunjie Wang,Yue Wang
Acetylacetone gas is a flammable, explosive, and toxic volatile compound with a pungent odor that can contaminate the atmospheric environment and pose a risk to human health. Consequently, establishing effective detection methods for acetylacetone is imperative. In this study, Co-doped ZnO (ZOC) were synthesized via a hydrothermal method with varying Co concentrations from 0 to 15 %, and used for the detection of acetylacetone for the first time. The sample with an 8 % Co/Zn mass ratio (8-ZOC) exhibits optimal gas sensing performance for acetylacetone. At a working temperature of 260 °C, the response to 100 ppm acetylacetone reaches up to 557.25, with a rapid response time of 6 s. Compared to pure ZnO, the response of 8-ZOC is increased by 5.9 times, and both the recovery time and the optimum operating temperature are reduced by 154 s and 40 °C, respectively. When exposed to UV light, the response value of 8-ZOC further improves to 682.49. Moreover, the underlying mechanisms of the enhanced gas sensing properties are also explored in detail. This research provides essential insights for the development of acetylacetone gas sensors.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Materials Science and Engineering B-Advanced Functional Solid-State Materials
·
2020
·
IF 4.706
Yuzhen Sun,Huifang Bi,Tao Wang,Leilei Sun,Zexin Li,Haining Song,Fenglei Sun,Haifeng Zhou,Guangjun Zhou,Jifan Hu
NaYF 4 :10Er/0.5Ho/30Ca@NaYF 4 is designed to achieve up-conversion luminescence color adjustment under 980 nm excitation. Ho 3+ doping enhances the red emission level of the system and changes the characteristic green emission into red emission. Importantly, Ho 3+ doping increases the difference in pumping time between green and red excited states. Under short pulse-width laser excitation, the red excited state does not have enough time to be populated, which weakens the emission of red emission, and the ratio of green to red emission will change. It is an effective up-conversion luminescence enhancement method to change the symmetry of crystal field around lanthanide ions by doping Ca 2+ . The green and red emission intensities of NaYF 4 :10Er/0.5Ho/30Ca doped with 30% Ca 2+ ions are 9.0 and 6.3 times higher than those of Ca 2+ free samples, respectively.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Bo-Mei Liu,Xiao-Xuan Guo,Lu-Yu Cao,Lin Huang,Rui Zou,Zhi Zhou,Jing Wang
The development of phosphor-converted light-emitting diodes (pc-LEDs) in the second near-infrared window (NIR-II, 1000–1700 nm) represents an important, newly emerging, and dynamic field in NIR spectroscopy. Unfortunately, lacking efficient NIR-II phosphors that can be excited by commercial blue LED chips impedes NIR spectroscopy applications. Herein, a donor–acceptor strategy is developed by introducing Cr 3+ sensitizers to greatly enhance the blue-light excitation efficiency of NIR-II-emitting MgO:Cr 3+ ,Ni 2+ phosphor. Consequently, a high-efficiency blue-light-excitable MgO:Cr 3+ ,Ni 2+ phosphor that gives a NIR-II emission at 1335 nm with a full width at half-maximum (FWHM) of 235 nm, is demonstrated. The product has a high internal quantum efficiency of 92.7 % and excellent thermal stability, maintaining 83.0 % of the room temperature emission intensity at 150 °C. Excitingly, the fabricated NIR-II pc-LED device shows a high NIR-II optical power (27.4 mW@350 mA). The performances of the achieved NIR-II pc-LED are almost the best results until now. Additionally, multifunctional applications including nondestructive detection and anti-counterfeiting of the NIR-II light source are demonstrated. These results are pretty crucial for the further development of NIR-II spectroscopy and imaging technology.
研究领域:
材料科学
·
光学工程
·
光谱学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL RESEARCH
·
2022
·
IF 1.097
Ruiji Li,Dong Wang,Xiaoyun Li,Zehui Zhang,Wei Li
Visible-light-excited fluorescent probes with excellent water solubility are of significant research importance in the biomedical field. In this work, a series of visible-light-responsive carbocyanine fluorescent compounds [DiSCn(3)] are synthesized from 2-methylbenzothiazole and are employed as fluorescent probes for detecting tin(II) ions. Upon addition of tin(II) ions to an aqueous solution of compounds DiSCn(3)-3 and 4, both exhibit considerable changes in their absorption and fluorescent intensity, respectively. These spectral changes may correspond to the binding between tin(II) ions and the sulfur atom in the benzothiazole unit to form a metal complex. This indicates that DiSCn(3)-3 and 4 can be used as promising fluorescent chemical sensors for detecting tin(II) ions in aqueous solution via visible-light excitation.
研究领域:
分析化学
·
生物医学
✓ 已验证
产品关联
DOI
高影响因子
Small
·
2023
·Vol. 19
·期 31
·2207046
·
IF 13.3
Dong Lu,Ke Lu,Hong-Tao Wen,Zhan Wei,Alberto Bianco,Gui-Gen Wang,Hua-Yu Zhang
The preparation of room temperature phosphorescent carbon dots still faces great challenges, especially in the case of carbon dots endowed of visible-light excitable room temperature phosphorescence (RTP). To date, a limited number of substrates have been exploited to synthesize room temperature phosphorescent carbon dots, and most of them can emit RTP only in solid state. Here, the synthesis of a composite obtained from the calcination of green carbon dots (g-CDs) blended with aluminum hydroxide (Al(OH) 3 ) is reported. The resultant hybrid material g-CDs@Al 2 O 3 exhibits blue fluorescence and green RTP emissions in an on/off switch process at 365 nm. Notably, this composite manifests strong resistance to extreme acid and basic conditions up to 30 days of treatment. The dense structure of Al 2 O 3 formed by calcination contributes to the phosphorescent emission of g-CDs. Surprisingly, g-CDs@Al 2 O 3 can also emit yellow RTP under irradiation with white light. The multicolor emissions can be employed for anti-counterfeiting and information encryption. This work provides a straightforward approach to produce room temperature phosphorescent carbon dots for a wide range of applications.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）