Cesium copper halides (CCHs) show promise for optoelectronic applications, and their syntheses usually involve high-temperatures and hazard solvents. Herein, the synthesis of highly luminescent and phase-pure Cs 3 Cu 2 X 5 (X = Cl, Br, and I) and CsCu 2 I 3 via a solvent-free mechanochemical approach through manual grinding is demonstrated. This costeffective approach can produce CCHs on a scale of tens to hundreds of grams. Rietveld refinement analysis of the X-ray diffraction patterns of the as-synthesized CCHs reveals their structural details. Notably, the emission characteristics of green-emitting, chloride-based CCHs remain stable even at elevated temperaturesmaintaining 80% of initial PL efficiency at 150 °C. Lastly, a postsynthetic reversible transformation between zero-and one-dimensional CCH materials is demonstrated, indicating the labile nature of their crystal structure. The proposed study suggests that mechanochemistry can be an alternative and promising synthetic tool for fabricating high-quality lead-free metal halides.

detection of these two sensory modalities can enhance the accuracy of the cognitive system further by providing complementary information between them. For example, the multimodal interactions to combine visual and tactile sensing information take place in the human brain to maximize the object recognition performance.As a visual-inspection method, X-ray detectors, which can examine the inside of the objects, have been implemented in various fields, such as industrial non-destructive testing, homeland security, and medical diagnostic imaging. [10][11][12][13][14][15][16] Although the X-ray inspection system is indispensable for the assessment of internal structures, which the human eye and optical cameras cannot observe, this X-ray inspection only provides visual information, which can limit the extension of its potential applications. [17] To improve the quality of inspection and diagnosis, the mapping of tactile pressure distributions should be used to detect excessive pressures, for example, the expansion of batteries before they explode and the fatigue failure of pipelines. Also, combining visual and tactile information makes it possible to diagnose various diseases (e.g., edema, scoliosis, and diabetes) by measuring additional pressure-related factors, such as body pressure and the circulation of blood, which cannot be measured by X-ray radiography alone. [18][19][20] Therefore, using a multimodal sensory platform that consists of X-ray detectors and tactile pressure sensors, which allows the simultaneous visuotactile imaging of the internal structures and external morphologies of target objects, can be an effective way to acquire accurate inspections.Metal halide perovskites are a new generation of semiconductor materials with extraordinary properties that allow the direct conversion of X-rays into electronic signals. Although these perovskites can be fabricated using a low-temperature solution process, their 3D integration capability for multiplexed sensory platforms has been limited due to their inherent vulnerability to the heat and moisture in the fabrication process, both of which degrade their remarkable optoelectronic properties. [21] Recently, direct-conversion X-ray detectors have been reported in which the perovskite layer is simply coated onto a commercially available Si transistor array for digitized pixel imaging. [14] However, the rigid and fragile form of this Si transistor Visual and tactile information are the key intuitive perceptions in sensory systems, and the synchronized detection of these two sensory modalities can enhance accuracy of object recognition by providing complementary information between them. Herein, multimodal integration of flexible, high-resolution X-ray detectors with a synchronous mapping of tactile pressure distributions for visualizing internal structures and morphologies of an object simultaneously is reported. As a visual-inspection method, perovskite materials that convert X-rays into charge carriers directly are synthesized. By incorporating pressure-sensitive ...

Increasing the stability of lead halide perovskites (LHPs) is required for integrating them into light-emitting devices. To date, most studies toward this direction have primarily concentrated on improving the chemical stability of green-emitting LHPs. In this work, red-emitting CsPbI 3 −Cs 4 PbI 6 hybrid nanocrystals (NCs) were synthesized with a high photoluminescence (PL) quantum yield of ∼90%. Their hybrid structure was examined via structural (Rietveld) refinement analysis and transmission electron microscopy. Rietveld refinement also revealed that the black polymorph of CsPbI 3 NCs is an orthorhombic perovskite rather than a cubic one. The thermodynamic stability of the CsPbI 3 NCs in Cs 4 PbI 6 matrices is enhanced in both solutions and films for up to several weeks. The enhanced stability of the embedded CsPbI 3 NCs is attributed to the lowering of their Gibbs free energy, as determined on the basis of experimental data. Additionally, the hybrid NCs exhibit unprecedented emission stabilitymaintaining 65% of their original PL efficiency at 150 °C and improved aqueous stability.