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31.
Shan He Runchen Lai Qike Jiang Yaoyao Han Xiao Luo Yuyang Tian Xue Liu Kaifeng Wu 《Angewandte Chemie (International ed. in English)》2020,59(40):17726-17731
Triplet energy transfer from inorganic nanocrystals to molecular acceptors has attracted strong attention for high‐efficiency photon upconversion. Here we study this problem using CsPbBr3 and CdSe nanocrystals as triplet donors and carboxylated anthracene isomers as acceptors. We find that the position of the carboxyl anchoring group on the molecule dictates the donor‐acceptor coupling to be either through‐bond or through‐space, while the relative strength of the two coupling pathways is controlled by the wavefunction leakage of nanocrystals that can be quantitatively tuned by nanocrystal sizes or shell thicknesses. By simultaneously engineering molecular geometry and nanocrystal wavefunction, energy transfer and photon upconversion efficiencies of a nanocrystal/molecule system can be improved by orders of magnitude. 相似文献
32.
Optical imaging plays a growing role in modern biomedical research and clinical applications due to its high sensitivity, superb spatiotemporal resolution and minimal hazards. Lanthanide‐doped nanoparticles (LDNPs), as a classical category of luminescent materials, exhibit promising photostability, near‐infrared (NIR)‐excited frequency up‐/down‐converting capabilities, emission fine‐tuning and multispectral features, which have greatly promoted the endeavors of deeper and clearer diagnostics in complex living conditions. This review focuses on the recent advances of LDNP‐based multipurpose imaging studies using upconversion, downshifting, lifetime, photoacoustic and multimodal nanoprobes in the NIR (650–1000 nm) and the second near‐infrared window (NIR‐II, 1000–1700 nm). The principle and design of various functional, activatable, multiplexing or multimodal lanthanide‐imaging nanoprobes (LINPs) as well as representative biophotonic applications are summarized in detail. In addition, the future perspectives and challenges for facilitating LINPs to clinical translations are discussed. 相似文献
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Xianquan Liao Yuxin Liu Qi Jia Prof. Jing Zhou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(43):11094-11101
Solar-driven photothermal antibacterial devices have attracted a lot of interest due to the fact that solar energy is one of the cleanest sources of energy in the world. However, conventional materials have a narrow absorbance band, resulting in deficient solar harvesting. In addition, lack of knowledge on temperature change in these devices during the photothermal process has also led to a waste of energy. Here, we presented an elegant multi-channel optical device with a multilayer structure to simultaneously address the above-mentioned issues in solar-driven antibacterial devices. In the photothermal channel, semiconductor IrO2-nanoaggregates exhibited higher solar absorbance and photothermal conversion efficiency compared with nanoparticles. In the luminescence channel, thermal-sensitive Er-doped upconversion nanoparticles were utilized to reflect the microscale temperature in real-time. The bacteria were successfully inactivated during the photothermal effect under solar irradiation with temperature monitoring. This study could provide valuable insight for the development of smart photothermal devices for solar-driven photothermal bacterial inactivation in the future. 相似文献
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采用溶胶-凝胶(Sol-gel)法制备了Er3+-Yb3+共掺杂Gd2Ti2O7纳米晶粉末,通过试验优化设计的理论建立了Er3+-Yb3+掺杂浓度与发光强度的回归方程,利用遗传算法优化计算出方程的最优解Er3+、Yb3+掺杂浓度分别为5.60%(物质的量分数)和13.43%。Er3+-Yb3+共掺杂Gd2Ti2O7纳米晶粉末为单一面心立方Gd2Ti2O7相结构,随Yb3+共掺杂浓度增加,X射线衍射峰逐渐向高角偏移。在976 nm激光激发下,Er3+-Yb3+共掺杂Gd2Ti2O7获得了分别对应于Er3+的2H11/2/4S3/2→4I15/2和4F9/2→4I15/2跃迁的绿色和红色上转换发光,且绿色和红色发光均为双光子吸收过程。研究了最优样品上转换发光与温度之间的关系,发现绿色上转换发光具有优良的温度传感特性,对红色上转换发光的温度猝灭进行了解释。 相似文献
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Yang Xu Ming Wu Yang Liu Prof. Dr. Xi‐Zeng Feng Prof. Dr. Xue‐Bo Yin Prof. Xi‐Wen He Prof. Yu‐Kui Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(7):2276-2283
Carbon dots (Cdots) are an important probe for imaging and sensing applications because of their fluorescence property, good biocompatibility, and low toxicity. However, complex procedures and strong acid treatment are often required and Cdots suffer from low photoluminescence (PL) emission. Herein, a facile and general strategy using carbonization of precursors and then extraction with solvents is proposed for the preparation of nitrogen‐doped Cdots (N‐Cdots) with 3‐(3,4‐dihydroxyphenyl)‐L ‐alanine (L ‐DOPA), L ‐histidine, and L ‐arginine as precursor models. After they are heated, the precursors become carbonized. Nitrogen‐doped Cdots are subsequently extracted into N,N′‐dimethylformamide (DMF) from the carbogenic solid. A core–shell structure of Cdots with a carbon core and the oxygen‐containing shell was observed. Nitrogen has different forms in N‐Cdots and oxidized N‐Cdots. The doped nitrogen and low oxidation level in N‐Cdots improve their emission significantly. The N‐Cdots show an emission with a nitrogen‐content‐dependent intensity and Cdot‐size‐dependent emission‐peak wavelength. Imaging of HeLa cells, a human cervical cancer cell line, and HepG2 cells, a human hepatocellular liver carcinoma line, was observed with high resolution using N‐Cdots as a probe and validates their use in imaging applications and their multicolor property in the living cell system. 相似文献
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采用溶胶-凝胶法制备Li+掺杂改性的Y2SiO5:Pr3+上转换发光材料,考察了Li+掺杂对样品晶型及发光性能的影响。采用XRD,DSC-TGA,FS对所制备的材料进行表征,结果表明Li+掺入浓度在7%~8%(摩尔分数)之间会引起Y2SiO5晶体类型由X1型转变为X2型,且Li+掺入后样品转晶型温度由950℃降至800℃;样品经800℃煅烧处理后以X1型Y2SiO5为主相,850℃煅烧处理后以X2型Y2SiO5为主相;Li+掺入同时会提高Y2SiO5:Pr3+材料的上转换发光强度,Li+最佳掺杂浓度为10%,对于双掺杂Pr3+,Li+:Y2SiO5体系中Pr3+最佳掺杂浓度为1.2%。 相似文献
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当使用液固溶法(LSS法)制备分散性纳米晶时,将传统油酸/油酸钠/酒精反应体系中的NaOH用氨水取代时,氨水将会与油酸形成新的表面活性剂油酸铵,这样就可以合成各种超细分散性的REF3纳米晶(RE代表稀土元素)。在这种新的反应体系中,合成了平均直径小于10nm的YF3和GdF3超细颗粒,X射线与透射电镜测试表明YF3是正交相,而GdF3是面心立方结构,空间群为Fm3m,晶格常数为0.5829nm。在980nm半导体激光器激发下,可检测到YF3:Yb/Er在515~570nm处有较强的绿色发光峰、645~675nm处有较强的红色发光峰,呈橙色发光。YF:Yb/Tm和GdF3:Yb/Tm样品在460~490nm处有较强的蓝色发光峰,而在800nm附近有更强的近红外发光峰。由于其超细的尺寸及红外上转换发光特性,合成的样品在生物成像,生物标签等方面有潜在的应用价值。 相似文献