II–VI semiconductor nanoplatelets have emerged as promising candidates for various applications, owing to their tunable optical properties dictated by their thickness and compositions. In the realm of infrared technology, mercury chalcogenides stand out as particularly promising materials for optoelectronic applications. However, the direct synthesis of 2D particles in this category remains challenging, thus prompting the exploration of alternative methods such as cation exchange. Here, we demonstrate that the cation exchange process from cadmium to mercury can be effectively catalyzed by monovalent Ag⁺ cations. This catalysis facilitates the formation of alloyed Hg_xCd_1–xSe nanoplatelets with tunable optical properties, with the photoluminescence peak ranging from 1.23 eV for the thinnest three-monolayer (ML) nanoplatelets to 0.92 eV for the thickest 7 ML nanoplatelets. The Ag⁺ ions reduce the activation energy of the cation exchange process by a factor of 2, enabling enhanced penetration of mercury atoms deep into the native CdSe nanoplatelets. Moreover, these nanoplatelets exhibit optical gain in the infrared spectrum, including the 1.3 μm telecommunication band, with a fluence threshold at 80 K of 50 μJ·cm^–2.

中文翻译：

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通过银离子催化的阳离子交换合成厚 HgxCd1–xSe 纳米片，显示出放大的自发发射


II-VI半导体纳米片已成为各种应用的有希望的候选者，因为它们的光学特性取决于其厚度和成分。在红外技术领域，汞硫属化物作为光电应用特别有前景的材料脱颖而出。然而，直接合成此类二维粒子仍然具有挑战性，因此促使人们探索阳离子交换等替代方法。在这里，我们证明单价 Ag ⁺ 阳离子可以有效催化从镉到汞的阳离子交换过程。这种催化作用促进了具有可调光学性质的合金化 Hg _x Cd _1–x Se 纳米片的形成，光致发光峰范围从最薄的三单层 (ML) 纳米片的 1.23 eV 到 0.92 eV最厚的 7 ML 纳米血小板的 eV。 Ag ⁺ 离子将阳离子交换过程的活化能降低了 2 倍，从而增强了汞原子深入天然 CdSe 纳米片的渗透。此外，这些纳米片在红外光谱（包括 1.3 μm 电信波段）中表现出光学增益，在 80 K 时的注量阈值为 50 μJ·cm ^–2 。