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121.
The Role of Oxygen in the Degradation of Methylammonium Lead Trihalide Perovskite Photoactive Layers 下载免费PDF全文
Nicholas Aristidou Dr. Irene Sanchez‐Molina Thana Chotchuangchutchaval Dr. Michael Brown Dr. Luis Martinez Dr. Thomas Rath Prof. Saif A. Haque 《Angewandte Chemie (International ed. in English)》2015,54(28):8208-8212
In this paper we report on the influence of light and oxygen on the stability of CH3NH3PbI3 perovskite‐based photoactive layers. When exposed to both light and dry air the mp‐Al2O3/CH3NH3PbI3 photoactive layers rapidly decompose yielding methylamine, PbI2, and I2 as products. We show that this degradation is initiated by the reaction of superoxide (O2?) with the methylammonium moiety of the perovskite absorber. Fluorescent molecular probe studies indicate that the O2? species is generated by the reaction of photoexcited electrons in the perovskite and molecular oxygen. We show that the yield of O2? generation is significantly reduced when the mp‐Al2O3 film is replaced with an mp‐TiO2 electron extraction and transport layer. The present findings suggest that replacing the methylammonium component in CH3NH3PbI3 to a species without acid protons could improve tolerance to oxygen and enhance stability. 相似文献
122.
123.
The SCISSORS method for approximating chemical similarities has shown excellent empirical performance on a number of real-world chemical data sets but lacks theoretically proven bounds on its worst-case error performance. This paper first proves reductions showing SCISSORS to be equivalent to two previous kernel methods: kernel principal components analysis and the rank-k Nystro?m approximation of a Gram matrix. These reductions allow the use of generalization bounds on these techniques to show that the expected error in SCISSORS approximations of molecular similarity kernels is bounded in expected pairwise inner product error, in matrix 2-norm and Frobenius norm for full kernel matrix approximations and in root-mean-square deviation for approximated matrices. Finally, we show that the actual performance of SCISSORS is significantly better than these worst-case bounds, indicating that chemical space is well-structured for chemical sampling algorithms. 相似文献
124.
125.
We describe an electrochemical oxidative desorption of benzenediazonium-grafted organic layers and immobilized proteins on the layers from indium-tin-oxide electrode surfaces. 相似文献
126.
We report in situ generation of aldehyde-functionalized benzenediazonium cation (ABD) and its use as a suitable linker molecule for fast and selective immobilization of biomolecules on indium-tin-oxide (ITO) electrode surfaces. We prepared ABD through a new reaction procedure, a simultaneous diazotation of the amine group and deprotection of the aldehyde group from an aniline derivative, 2-(4-aminophenyl)-1,3-dithiane, which was revealed on the ITO electrode surfaces through the electrodeposition of the reaction product and the characterization of the resulting surfaces with cyclic voltammetry, X-ray photoelectron spectroscopy, and protein immobilization. We also showed that successive electrodeposition of ABD and probe molecules on individually addressable microarray electrode surfaces can provide a useful platform for efficient detection of multianalyte. The usage of ABD has been demonstrated by the patterning of three different probe molecules on a single substrate and the simultaneous detection of two target molecules. 相似文献
127.
M. Anamul Haque M. Muhibur Rahman M. Abu Bin Hasan Susan 《Journal of solution chemistry》2012,41(3):447-457
The electrochemical behavior of an anthraquinone (AQ) was studied in aqueous solutions at a glassy carbon electrode, using
the sodium salt of anthraquinone-2-sulfonic acid (AQS), by employing cyclic voltammetry. AQ undergoes a two-electron reduction
in aqueous media. The electrochemical behavior of AQ was also investigated in micelles, reverse micelles (CTAB/1-butanol/water),
and microemulsions (CTAB/1-butanol/water/cyclohexane) of cetyltrimethylammonium bromide (CTAB). The electrode reactions of
AQ in reverse micelles and microemulsions are nearly reversible at low oil (cyclohexane) content. However, at higher oil content,
the reversibility is gradually lost. In the case of reverse micelles, the reduction current, as well as the reduction potential,
of AQ depend on the transition from a micellar solution to a stable solution of reverse micelles that occurs with added 1-butanol.
In microemulsions, the change in cyclohexane content was found to cause a linear increase in the peak current for AQ reduction
as well as a linear decrease in the corresponding reduction potential. As the cyclohexane content is increased, the o/w microemulsions
dominated by micelles undergo a transition to a w/o microemulsion dominated by reverse micelles, which causes changes in the
electrochemical behavior. 相似文献
128.
Sarker ZI Elgadir MA Ferdosh S Akanda JH Manap MY Noda T 《Molecules (Basel, Switzerland)》2012,17(5):5733-5744
The objective of this study was to investigate the effect of selected biopolymers on the rheological properties of surimi. In our paper, we highlight the functional properties and rheological aspects of some starch mixtures used in surimi. However, the influence of some other ingredients, such as cryoprotectants, mannans, and hydroxylpropylmethylcellulose (HPMC), on the rheological properties of surimi is also described. The outcome reveals that storage modulus increased with the addition of higher levels of starch. Moreover, the increasing starch level increased the breaking force, deformation, and gel strength of surimi as a result of the absorption of water by starch granules in the mixture to make the surimi more rigid. On the other hand, the addition of cryoprotectants, mannans, and HPMC improved the rheological properties of surimi. The data obtained in this paper could be beneficial particularly to the scientists who deal with food processing field. 相似文献
129.
Saeed MA Pramanik A Wong BM Haque SA Powell DR Chand DK Hossain MA 《Chemical communications (Cambridge, England)》2012,48(69):8631-8633
An unanticipated anion-water cluster is assembled by one bromide and three highly-ordered "water tetramers" within the cavity of a receptor, providing a perfect C(3) symmetric propeller-shaped bromide-water cluster of [Br(H(2)O)(12)](-). 相似文献
130.
The petroleum ether and chloroform extracts of the root of Piper chaba showed antimicrobial, antileishmanial and cytotoxic activities. Further bioactivity-guided fractionation led to the isolation of Bornyl piperate (1), piperlonguminine (2) and piperine (3). This is the first report of isolation of compounds (1) and (2) from P. chaba. It was observed that the isolated compounds (1 and 2) showed potent antifungal activity when compared with standard drug Nystatin, and significant cytotoxic activity with the IC?? values of 0.76 and 0.83?μg?mL?1, respectively. These compounds were also found to have weak antibacterial and antileishmanial activities. This is the first report about the antileishmanial activity of Piper isolates. 相似文献