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Piezochromic materials refer to a class of matters that alter their photoluminescence (PL) colors in response to the external stimuli, which exhibit promising smart applications in anti‐counterfeiting, optoelectronic memory and pressure‐sensing. However, so far, most reported piezochromic materials have been confined to organic materials or hybrid materials containing organic moieties with limited piezochromic range of less than 100 nm in visible region. Here, we achieved an intriguing piezochromism in all‐inorganic zero‐dimensional (0D) Cs3Cu2Cl5 nanocrystals (NCs) with a considerable piezochromic range of 232 nm because of their unique inorganic rigid structure. The PL energy shifted from the lowest‐energy red fluorescence (1.85 eV) to the highest‐energy blue fluorescence (2.83 eV), covering almost the entire visible wavelength range. Pressure‐modulated self‐trapped exciton emission between different energy levels of self‐trapped states within Cs3Cu2Cl5 NCs was the main reason for this piezochromism property. Note that the quenched emission, which is over five times more intense than that in the initial state, is retained under ambient conditions upon decompression. This work provides a promising pressure indicating material, particularly used in pressure stability monitoring for equipment working at extreme environments. [ABSTRACT FROM AUTHOR]

Piezochromic materials refer to a class of matters that alter their photoluminescence (PL) colors in response to the external stimuli, which exhibit promising smart applications in anti‐counterfeiting, optoelectronic memory and pressure‐sensing. However, so far, most reported piezochromic materials have been confined to organic materials or hybrid materials containing organic moieties with limited piezochromic range of less than 100 nm in visible region. Here, we achieved an intriguing piezochromism in all‐inorganic zero‐dimensional (0D) Cs3Cu2Cl5 nanocrystals (NCs) with a considerable piezochromic range of 232 nm because of their unique inorganic rigid structure. The PL energy shifted from the lowest‐energy red fluorescence (1.85 eV) to the highest‐energy blue fluorescence (2.83 eV), covering almost the entire visible wavelength range. Pressure‐modulated self‐trapped exciton emission between different energy levels of self‐trapped states within Cs3Cu2Cl5 NCs was the main reason for this piezochromism property. Note that the quenched emission, which is over five times more intense than that in the initial state, is retained under ambient conditions upon decompression. This work provides a promising pressure indicating material, particularly used in pressure stability monitoring for equipment working at extreme environments. [ABSTRACT FROM AUTHOR]

A recent research article published in Angewandte Chemie by Guanjun Xiao et al. discusses the discovery of an all-inorganic zero-dimensional metal-halide perovskite with a significant piezochromic range. The researchers used a diamond anvil cell to observe the pressure-induced piezochromic behavior in Cs3Cu2Cl5 nanocrystals. The nanocrystals exhibited a shift in emission energy from red fluorescence to blue fluorescence, covering the entire visible wavelength range. This discovery has potential applications in visual pressure monitoring and sensing. [Extracted from the article]

A research article published in Angewandte Chemie International Edition by Guanjun Xiao et al. discusses the discovery of an all-inorganic zero-dimensional metal-halide perovskite with a significant piezochromic range of 232 nm. The article describes the use of a diamond anvil cell to observe pressure-induced piezochromic behavior in Cs3Cu2Cl5 nanocrystals. The nanocrystals exhibited a shift in emission energy from red fluorescence to blue fluorescence, covering the entire visible wavelength range. This discovery has potential applications in visual pressure monitoring and sensing. [Extracted from the article]

[Display omitted] • 1. AFM-based biophysical measurements are performed on a neural cell. • 2. Exposure to high-dose carbon dots affects cellular mechanics and morphology. • 3. Actin filaments are disorganized in the cells after exposure to high-dose carbon dots. • 4. Biological studies validate the cytotoxic effects disclosed by AFM. • 5. AFM is a powerful biophysical tool for the study of cell-nanomaterials interactions. Understanding the cytotoxicity of fluorescent carbon dots (CDs) is crucial for their applications, and various biochemical assays have been used to study the effects of CDs on cells. Knowledge on the effects of CDs from a biophysical perspective is integral to the recognition of their cytotoxicity, however the related information is very limited. Here, we report that atomic force microscopy (AFM) can be used as an effective tool for studying the effects of CDs on cells from the biophysical perspective. We achieve this by integrating AFM-based nanomechanics with AFM-based imaging. We demonstrate the performance of this method by measuring the influence of CDs on living human neuroblastoma (SH-SY5Y) cells at the single-cell level. We find that high-dose CDs can mechanically induce elevated normalized hysteresis (energy dissipation during the cell deformation) and structurally impair actin skeleton. The nanomechanical change highly correlates with the alteration of actin filaments, indicating that CDs-induced changes in SH-SY5Y cells are revealed in-depth from the AFM-based biophysical aspect. We validate the reliability of the biophysical observations using conventional biological methods including cell viability test, fluorescent microscopy, and western blot assay. Our work contributes new and significant information on the cytotoxicity of CDs from the biophysical perspective. [ABSTRACT FROM AUTHOR]

The engineering activities of deep stratigraphic resources development and space utilization are often subjected to complex stress conditions. In terms of gas-bearing coal resource mining, the dynamic mechanical properties of coal at complex loaded stress and gas environment were researched in this paper. Through the split Hopkinson pressure bar (SHPB), the dynamics experiments were performed, in which the factors of axial static load, circumferential confining pressure, internal gas pressure, and outside impact load were considered. Based on the stress and strain results of gas-bearing coal, the dynamic compressive strength and peak failure strain characteristics with strain rates were obtained. Under different loaded conditions, both dynamic compressive strength and peak failure strain added linearly along with strain rates increasing. In fact, high strain rates were the results of comprehensive loading conditions, so the effects of them to coal mechanical properties were discussed. And the improved dynamic material model of gas-bearing coal at high strain rates was proposed, which considered pre-damage of static load, hardening effects of strain rate, and weakening role of gas. Through using this model in numerical simulation, the plastic deformation and stress distribution of coal specimens subjected to impact failure were researched, which verified the results of dynamics experiments. Dynamics achievements of gas-bearing coal at complex loaded environment will provide guides for disaster prevention and promote green mining. [ABSTRACT FROM AUTHOR]

To reveal fracture mechanism of gas-bearing coal subjected to complex geology environment, the impact dynamics experiments were conducted to study energy characteristics based on split Hopkinson pressure bar (SHPB) system. The incident, reflected and transmission strain were collected to calculate various energy. It was found reflected strain was always larger than transmission strain. Therefore, the reflected energy was generally higher than transmission energy under different loading conditions, but they were smaller than incident energy. With time evolution, both elastic deformation and dissipative energy experienced slow increase, rapid increase, peak point and decrease stage regardless of loading conditions. Before macro failure, micro-meso fractures had changed drasticly, which also involved intense energy conversion. So dissipative energy peak was earlier than that of elastic deformation energy. Due to pre-damage of static load and weakening effects of gas, the dissipative energy decreased with their increases (static load from 2.00 to 9.00 MPa and gas pressure from 0.25 to 1.50 MPa) during impact fracture process. However, at high confining pressure and dynamic load environment, the impact failure of gas-bearing coal exhausted massive energy. These energy characteristics will provide guidances to prevent and control disaster during coal mining and coal seam gas (CSG) exploitation in deep area. [Display omitted] • Instant strain characteristics of gas-bearing coal were analyzed under dynamic load. • Energy dissipation mechanism of gas-bearing coal were revealed during impact process. • The effects of loading conditions to energy evolution of gas-bearing coal were discussed. [ABSTRACT FROM AUTHOR]