ACS ENERGY LETTERS,2018年3(11):2713-2720 ISSN：2380-8195
Li, Wei;Prezhdo, Oleg V.
[Tang, Jianfeng; Li, Wei] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.;[Casanova, David] DIPC, Donostia San Sebastian 20018, Euskadi, Spain.;[Casanova, David] IKERBASQUE, Basque Fdn Sci, Bilbao 48013, Euskadi, Spain.;[Prezhdo, Oleg V.] Univ Southern Calif, Dept Chem, Los Angeles, CA 90089 USA.
[Li, Wei] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.;[Prezhdo, Oleg V.] Univ Southern Calif, Dept Chem, Los Angeles, CA 90089 USA.
Increased charge carrier lifetimes at elevated temperatures constitute an intriguing and valuable feature of hybrid organic inorganic perovskites that are subject to heating in solar energy applications. We rationalize this peculiar behavior at the atomistic level using real-time time dependent density functional theory and nonadiabatic molecular dynamics. Focusing on tetragonal MAPbI(3), we demonstrate that temperature has different effects on the organic and inorganic subsystems and leads to subtle structural changes, decreasing nonradiative electron hole recombination. First, charge-phonon interactions are decreased because the libration dynamics of the organic component at higher temperature reduces the oscillation amplitude of the Pb-I lattice that supports electrons and holes. Second, thermal disorder localizes wave functions, reducing the nonadiabatic charge phonon coupling. Third, tilting of the inorganic octahedra increases the bandgap, extending charge carrier lifetime further. The detailed time-domain atomistic analysis of the uncommon dependence of charge recombination on temperature emphasizes the key role played by the organic cation, establishes important structure property relationships, provides valuable insights into efficient performance of perovskite solar cells, and highlights factors required to maintain and improve such performance.
Feature extraction plays a great important role in image processing and pattern recognition. As a power tool, multifractal theory is recently employed for this job. However, traditional multifractal methods are proposed to analyze the objects with stationary measure and cannot for non-stationary measure. The works of this paper is twofold. First, the definition of stationary image and 2D image feature detection methods are proposed. Second, a novel feature extraction scheme for non-stationary image is proposed by local multifractal detrended fluctuation analysis (Local MF-DFA), which is based on 2D MF-DFA. A set of new multifractal descriptors, called local generalized Hurst exponent (Lh<inf>q</inf>) is defined to characterize the local scaling properties of textures. To test the proposed method, both the novel texture descriptor and other two multifractal indicators, namely, local Hölder coefficients based on capacity measure and multifractal dimension D<inf>q</inf> based on multifractal differential box-counting (MDBC) method, are compared in segmentation experiments. The first experiment indicates that the segmentation results obtained by the proposed Lh<inf>q</inf> are better than the MDBC-based D<inf>q</inf> slightly and superior to the local Hölder coefficients significantly. The results in the second experiment demonstrate that the Lh<inf>q</inf> can distinguish the texture images more effectively and provide more robust segmentations than the MDBC-based D<inf>q</inf> significantly.
In this paper, we consider the compressible Navier-Stokes-Korteweg system that models the motions of the compressible isothermal viscous capillary fluids. We prove the global existence of a strong solution to the compressible Navier-Stokes-Korteweg system when the initial perturbation lips parallel to rho(0) - (rho) over cap parallel to(H2) + parallel to u(0)parallel to(H1) is small. Furthermore, if the L-1 norm of the initial perturbation is finite, we can obtain the optimal L-2 decay rates. (C) 2012 Elsevier Inc. All rights reserved.
Regioselective azotization or bis(amination) products of the title porphyrinoid were achieved in one-pot one-step syntheses under mild conditions using a selection of aromatic amines and isoamyl nitrite or p-chloranil, respectively. Structures, tautomery, chirality as well as spectroscopic and redox properties of the new systems were discussed.
Identification and quantification of small organic molecules capable of binding to a protein of interest with reasonable affinity and specificity is a central problem. Via developing DNA-encoded recognizing probe, we validate a proof-of-principle for constructing of small target-to-DNA conversion that screens the small molecule-protein interaction. Successful identification of beta-indole acetic acid, abscisic acid, or 2,4-dichlorophenoxyacetic acid/corresponding antibody binding implies its fascinating potential for interrogating small molecule/protein interaction.