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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]

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]