Liposome is well known as not only a drug-delivery system but also a simple model for biological membranes. It was reported that fluorescence properties of hypocrellins were changeable over some extreme pH values. In the current work, the effects of the microenvironments on the fluorescence properties of HB in liposome, including approximately physiological range of pH values pH = 6.0-8.0, concentration of cholesterols and ionic strength of the solution, were studied. It was found that the fluorescence intensity of HB was sensitive to and also regulated by the microenvironments. When concentration of cholesterols and ionic strength keep invariable in PBS solution, there exists the maximum for the fluorescence of HB-liposome at pH 7.4 while the minimum for that of HB at pH 7.0. In addition, when pH value keeps constant (7.2), there exists the maximum at the ionic strength of 0.12 mol/kg while that at the concentration of 6×10?4 mol/L for cholesterols. On the other hand, in PBS solution, the lower the ionic strength is, the higher the fluorescence intensity is. The environment-sensitive fluorescence may be potentially applicable to probe some specific environmental features in cells or tissues.
By intelligently utilizing the odd-even effect existing in the melting points of alkanes as presented in the basic textbook of Organic Chemistry, different alkoxy groups were introduced to modify the structure of commercial Spiro-OMeTAD to give new Spiro derivatives of Spiro-OEtTAD, Spiro-OPrTAD, Spiro-OiPrTAD and Spiro-OBuTAD, with the aim to adjust the molecular packing status in perovskite solar cells as hole transporting compounds. Excitedly, with the introduction of ethoxy groups instead of the methoxy ones in Spiro-OMeTAD, Spiro-OEtTAD-based perovskite solar cells demonstrated the highest device performance of 20.16%, higher than that of Spiro-OMeTAD(18.64%). 相似文献
Liposome is well known as not only a drug-delivery system but also a simple model for biological membranes. It was reported
that fluorescence properties of hypocrellins were changeable over some extreme pH values. In the current work, the effects
of the microenvironments on the fluorescence properties of HB in liposome, including approximately physiological range of
pH values pH = 6.0-8.0, concentration of cholesterols and ionic strength of the solution, were studied. It was found that
the fluorescence intensity of HB was sensitive to and also regulated by the microenvironments. When concentration of cholesterols
and ionic strength keep invariable in PBS solution, there exists the maximum for the fluorescence of HB-liposome at pH 7.4
while the minimum for that of HB at pH 7.0. In addition, when pH value keeps constant (7.2), there exists the maximum at the
ionic strength of 0.12 mol/kg while that at the concentration of 6×10−4 mol/L for cholesterols. On the other hand, in PBS solution, the lower the ionic strength is, the higher the fluorescence
intensity is. The environment-sensitive fluorescence may be potentially applicable to probe some specific environmental features
in cells or tissues. 相似文献
The identification of the contribution of different surface sites to the catalytic activity of a catalyst nanoparticle is one of the most challenging issues in the fundamental studies of heterogeneous catalysis. We herein demonstrate an effective strategy of using a series of uniform cubic Cu2O nanocrystals with different sizes to identify the intrinsic activity and contributions of face and edge sites in the catalysis of CO oxidation by a combination of reaction kinetics analysis and DFT calculations. Cu2O nanocrystals undergo in situ surface oxidation forming CuO thin films during CO oxidation. As the average size of the cubic Cu2O nanocrystals decreases from 1029 nm to 34 nm, the dominant active sites contributing to the catalytic activity switch from face sites to edge sites. These results reveal the interplay between the intrinsic catalytic activity and the density of individual types of surface sites on a catalyst nanoparticle in determining their contributions to the catalytic activity. 相似文献
P‐type Cu2O has been long considered as an attractive photocatalyst for photocatalytic water reduction, but few successful examples has been reported. Here, we report the synthesis of TiO2 (core)/Cu2O (ultrathin film shell) nanorods by a redox reaction between Cu2+ and in‐situ generated Ti3+ when Cu2+‐exchanged H‐titanate nanotubes are calcined in air. Owing to the strong TiO2‐Cu2O interfacial interaction, TiO2 (core)/Cu2O (ultrathin film shell) nanorods are highly active and stable in photocatalytic water reduction. The TiO2 core and Cu2O ultrathin film shell respectively act as the photosensitizer and cocatalyst, and both the photoexcited electrons in the conduction band and the holes in the valence band of TiO2 respectively transfer to the conduction band and valence band of the Cu2O ultrathin film shell. Our results unambiguously show that Cu2O itself can act as the highly active and stable cocatalyst for photocatalytic water reduction. 相似文献
Reaching the full potential of solar cells based on photo-absorbers of organic-inorganic hybrid perovskites requires highly efficient charge extraction at the interface between perovskite and charge transporting layer. This demand is generally challenged by the presence of under-coordinated metal or halogen ions, causing surface charge trapping and resultant recombination losses. These problems can be tackled by introducing a small molecule interfacial anchor layer based on dimethylbiguanide (DMBG). Benefitting from interactions between the nitrogen-containing functional groups in DMBG and unsaturated ions in CH3NH3PbI3 perovskites, the electron extraction of TiO2 is dramatically improved in association with reduced Schottky–Read–Hall recombination, as revealed by photoluminescence spectroscopy. As a consequence, the power conversion efficiency of CH3NH3PbI3 solar cells is boosted from 17.14 to 19.1 %, showing appreciably reduced hysteresis. The demonstrated molecular strategy based on DMBG enables one to achieve meliorations on key figures of merit in halide perovskite solar cells with improved stability. 相似文献
Hypocrellins (HA or HB) were well known as novel photosensitizers for photodynamic therapy (PDT). The investigations on their photophysical and photochemical properties have been carried out inten-sively in the past 20 years[1—4]. Intramolecular hydro-gen bonds are formed in a hypocrellin molecule, so are intramolecular proton transfers at the excited state, which has been proved to be essential for the fluores-cence emission of hypocrellins[5]. The two phenolic hydroxyl groups in a hypocr… 相似文献