The PAN/TiO 2 /Ag nanofibers membrane for air filtration media was successfully synthesized with electrospinning method. The morphology, size, and element percentage of the nanofiber were characterized by a scanning electron microscopy–energy dispersive spectroscopy, while X-ray fluorescence and FTIR were used to observe the chemical composition. The water contact angle and UV–vis absorption were measured for physical properties. Performance for air filtration media was measured by pressure drop, efficiency, and quality factor test. TiO 2 and Ag have been successfully deposited in nonuniform 570 nm PAN/TiO 2 /Ag nanofibers. The nanofiber membrane had hydrophilic surface after TiO 2 and Ag addition with a water contact angle of 34.58°. UV–vis data showed the shifting of absorbance and band gap energy of nanofibers membrane to visible light from 3.8 to 1.8 eV. The 60 min spun PAN/TiO 2 /Ag nanofibers membrane had a 96.9% efficiency of PM 2.5 , comparable to results reported in previous studies. These properties were suitable to be applied on air filtration media with photocatalytic activity for self-cleaning performance.

Scintillators fabricated from organic–inorganic layered perovskites have attracted wide attention due to their excellent properties, including fast decay times, superior light yield, and high exciton binding energy. In relation to their optoelectronic properties, hybrid organic–inorganic perovskites are known for their tunability, which could be manipulated by modifying the organic cations. In this study, we investigate the optical and scintillation properties of lead halide perovskites A2PbBr4, where A vary from amylammonium (AA), hexylammonium (HA), octylammonium (OA), and benzylammonium (BZA) organic ligands. Photoluminescence (PL) spectra display dual peaks due to surface and bulk trap states contributions, while fast average decay times from time-resolved photoluminescence (TRPL) for all samples are within the range of 0.69 ± 0.11–0.99 ± 0.13 ns. The optical band gap of these hybrid perovskites is within ∼3 eV range, which fulfill the criteria of promising scintillators. Radioluminescence (RL) spectra show negative thermal quenching behavior (NTQ) in all samples, with the AA2PbBr4 peak intensity appearing at relatively lower temperature compared to other samples. Thermoluminescence (TL) measurement reveals trap-free states in AA2PbBr4, while other samples possess shallow traps (<40 meV) as well as low trap density, which is beneficial for fast-decay scintillators, X-ray detection and energy conversion for solar cells. Overall, our results demonstrate that the extension of linear organic chains in lead-based perovskite is a deterministic strategy for a fast response hybrid-based scintillator to date.

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The tunable control in the inorganic octahedral framework of hybrid perovskites offers potential applications in photovoltaics, solid-state lighting, and radiation detection. However, the implication of the structure and optoelectronic properties pose challenges due to competition between organic–inorganic coupling and intraoctahedral interactions. In this study, we combine X-ray absorption spectroscopy (XAS) and Raman analysis to interpret the angular-dependent behavior and anharmonicity of manganese-based single-crystal perovskites differing by a single methylene unit. The XAS spectra of manganese-based single-crystal perovskites with 2-phenethylamine (PEA) compared to 3-phenyl-1-propylamine (PPA) as organic cations unambiguously demonstrated a 180° intensity shift as a function of the incoming photon, suggesting a pronounced structural ligand variation. The out-of-plane polarization is found to be more prominent in L2-edge than in L3. In addition, an accompanying shoulder peak around 643 eV was attributed to the electron excitation from Mn 2p to 3d orbitals to form d5L states. A decrease in terms of field strength is prominently observed that infers a low crystal field splitting energy. Raman analysis of the two hybrid perovskites displays a notable difference in the respective translational modes at 84 and 87 cm–1, which signifies the amplified anharmonicity due to extended chain length. Based on this phenomenological approach, a longer chain promotes a rather unique octahedral deformation than anharmonicity shift that is crucially important to decoupling the nature of the active units. This effort sheds some light to implement the orientational ordering toward an efficient charge transport of hybrid perovskite semiconductors.

There are works have reported the crystal structures and mechanical properties of ferrite cement (C4AF) at the atomic scale with deviation owing to the omission of the Coulomb interaction effect (Ueff) between 3d electrons of Fe in C4AF. In this work, the DFT+U method was used to evaluate its effect on their electronic structures and mechanical properties of C4AF with two different phases I2mb (C4AF‐I) and Pnma (C4AF‐P). The Fe‐O bonds of the two phases are all weaker and display Ueff due to the presence of Fe ions. The mechanical properties of C4AF calculated using DFT+U method significantly differ from those obtained without considering Ueff, in which the former shows lower inferior mechanical properties than the latter. This work presents a comparative study the effect of Coulomb interaction to the internal electronic structures and mechanical properties, which will pave the way for designing high hydration reaction cement and high toughness materials.This article is protected by copyright. All rights reserved