Lead‐Free Cesium Manganese Halide Nanocrystals Embedded Glasses for X‐Ray Imaging

Abstract

The toxicity of heavy-metal Pb and instability of lead-based halide perovskite nanomaterials are main factors to impede their practical applications in the fields of solar cells, LEDs and scintillators. In this paper, all inorganic lead-free cesium manganese halide nanocrystals are synthesized in glass for the first time. Red photoluminescence with broad PL band, negligible self-absorption and a high photoluminescence quantum yield of 41.8% is obtained. In addition, modulating halide component can change the Mn 2+ ions coordination environment to obtain tunable photoluminescence from red to green. More importantly, cesium manganese halide nanocrystals embedded glasses exhibit outstanding long-term stabilities. Theses cesium manganese halide nanocrystals embedded glasses are also highly stable against high energy irradiation and exhibit highly efficient radioluminescence, making them promising for high-resolution X-ray imaging. These results demonstrate that cesium manganese halide nanocrystals embedded glasses are promising eco-friendly candidates for applications in light-emitting diodes and scintillators.

Solid-state synthesis of cesium manganese halide nanocrystals in glass with bright and broad red emission for white LEDs

“…2). In contrast to previous studies, 28,29,33,36 these CsMnBr 3 nanocrystal embedded glass samples with a larger FWHM are more suitable for solid-state lighting (Fig. 2).…”

“…The larger FWHM may be ascribed to the glass matrix. 33,37 In order to explore the origin of red emission, PL excitation (PLE) spectra are recorded (Fig. 1b).…”

“…Very recently, Liu et al reported that the CsMnX 3 NCs embedded glass with highest PL QY of 41.8% (CsMnCl 3 ) for X-ray imaging. 33 However, there is obvious absorption peaks in the 500-550 nm region of the UVvis absorption spectra of the CsMnX 3 NCs, indicatindg the existence of Mn 3+ . 34 Therefore, it is urgent to develop new methods to improve the stability of the manganese halide NCs.…”

Regulating the Optical Properties of Cs3MnBr5 Nanocrystals in Glasses for Narrow-Band Green Emission

“…The heat-treated Z00 specimens show three absorption peaks at 439, 455, and 475 nm, corresponding to the 6 A 1 → 4 A 1 , 4 E(G), 6 A 1 → 4 T 2 (G), and 6 A 1 → 4 T 1 (G) transitions of Mn 2+ ions in tetrahedral coordination, respectively. 36 With the increase in the heattreatment temperature, absorption coefficients of these three peaks are enhanced (Figure 2a). Changes in the local environment of Mn 2+ ions also significantly affect their PL properties (Figure 2b).…”

“…The polymer matrix employed is also inclined to undergo degradation and structural damage under long-term high-energy irradiation. Wrapping the red-emitting CsMnX 3 (X = Cl, Br, and I) NCs in inorganic glasses through melt-quenching and subsequent thermal treatment have been proved to improve their stability against high-energy laser irradiation, moisture, and heat. , To the best of our knowledge, green-emitting cesium manganese halide NCs with a high PL QY and good stability have not been precipitated in glasses until now.…”