The conduction band dispersion in methylammonium lead iodide (CHNHPbI) was studied by both angle-resolved two-photon photoelectron spectroscopy (AR-2PPE) with low photon intensity (∼0.0125 nJ/pulse) and angle-resolved low-energy inverse photoelectron spectroscopy (AR-LEIPS). Clear energy dispersion of the conduction band along the Γ-M direction was first observed by these independent methods under different temperatures, and the dispersion was found to be consistent with band calculation under the cubic phase. The effective mass of the electrons at the Γ point was estimated to be (0.20 ± 0.05) at the temperature of 90 K. The observed conduction band energy was different between the AR-LEIPS and AR-2PPE, which was ascribed to the electronic-correlation-dependent difference of initial and final states probing processes. The present results also indicate that the surface structure in CHNHPbI provides the cubic-dominated electronic property even at lower temperatures.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/acs.jpclett.1c00530 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Exploring the role of quantitative electroencephalography in ischaemic stroke through spectral and topographic mapping.
Med J Malaysia
January 2025
National University of Malaysia, Faculty of Medicine, Department of Medicine, Kuala Lumpur, Malaysia.
Introduction: Stroke is a major cause of morbidity and mortality worldwide. While electroencephalography (EEG) offers valuable data on post-stroke brain activity, qualitative EEG assessments may be misinterpreted. Therefore, we examined the potential of quantitative EEG (qEEG) to identify key band frequencies that could serve as potential electrophysiological biomarkers in stroke patients.
View Article and Find Full Text PDFHalogen-Free Wide Band Gap Polymer Donors Based on Dicyanobithiophene for Efficient Organic Solar Cells.
ACS Appl Mater Interfaces
January 2025
Conjugated polymer donors have always been one of the important components of organic solar cells (OSCs), particularly those featuring simple synthetic routes, proper energy levels, and appropriate aggregation behavior. In this work, we employed a nonfused electron-deficient building block, dicyanobithiophene (2CT), for constructing high-performance donors. Combining this with side-chain engineering, two novel halogen-free polymer donors, PB2CT-BO and PB2CT-HD, were reported.
View Article and Find Full Text PDFDeciphering the Photophysical Properties of Nonplanar Heterocyclic Compounds in Different Polarity Environments.
J Phys Chem B
January 2025
Materials Chemistry Department, CSIR-Institute of Minerals and Materials Technology, Bhubaneswar 751013, India.
Nonplanar (butterfly-shaped) phenothiazine () and its derivative's () photophysical and spectral properties have been tuned by varying the solvents and their polarity and investigated employing spectroscopic techniques such as UV-Vis, steady-state and time-resolved fluorescence, and TDDFT calculations. The UV-Vis absorption studies and TDDFT calculations reveal two distinct bands for both compounds: a strong π-π* transition at shorter wavelengths and a weaker -π* transition, which displays a little bathochromic shift in polar solvents. The detailed emission studies reveal that such dual emission is a result of the photoinduced excited-state conjugation enhancement (ESCE) process.
View Article and Find Full Text PDFTunnel barriers for Fe-based spin valves providing high spin-polarized current.
Phys Chem Chem Phys
January 2025
King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division (PSE), Thuwal 23955-6900, Saudi Arabia.
Employing density functional theory for ground state quantum mechanical calculations and the non-equilibrium Green's function method for transport calculations, we investigate the potential of CdS, ZnS, CdZnS, and ZnCdS as tunnel barriers in magnetic tunnel junctions for spintronics. Based on the finding that the valence band edges of these semiconductors are dominated by p orbitals and the conduction band edges by s orbitals, we show that symmetry filtering of the Bloch states in magnetic tunnel junctions with Fe electrodes results in high tunneling magnetoresistances and high spin-polarized current (up to two orders of magnitude higher than in the case of the Fe/MgO/Fe magnetic tunnel junction).
View Article and Find Full Text PDFStudy of spectral overlap and heterogeneity in agriculture based on soft classification techniques.
MethodsX
June 2025
Department of Biological and Pharmaceutical Environmental Sciences and Technologies, University of Campania "L. Vanvitelli", Via Antonio Vivaldi, 43, Caserta 81100, CE, Italy.
This study explores the application of fuzzy soft classification techniques combined with vegetation indices to address spectral overlap and heterogeneity in agricultural image processing. The methodology focuses on the integration of three key vegetation indices: Soil-Adjusted Vegetation Index (SAVI), Modified Soil-Adjusted Vegetation Index (MSAVI), and Modified Chlorophyll Absorption in Reflectance Index (MCARI), with Modified Possibilistic C-Means (MPCM) clustering. The analysis involves preprocessing the image data, calculating the vegetation indices, and applying the MPCM algorithm to perform soft classification, allowing pixels to belong to multiple classes with varying degrees of membership.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!