Abstract Although quantum dots (QDs) based on two dimensional (2D) materials have manifested fascinating properties and promising applications in a wide range of fields, a low cost and non-tedious approach for the preparation of atomically thick 2D QDs with high yield remains elusive. Herein, for the first time, we demonstrate a reflux pretreatment-mediated sonication approach to produce a series of ultrathin 2D QDs (e.g., graphene, TiS2, MoS2, MoSe2, WSe2, NbS2, SnS2, and h-BN QDs) from their bulk counterparts. The solvent molecules, confined in the channels of layered materials during reflux, assist the delamination and fracture of 2D sheets in the process of bath sonication. The resulting 2D QDs exhibited uniform lateral size distribution of 2–7 nm and a mean thickness of 0.8–1 nm, almost identical to the monolayer thickness of layered materials. To demonstrate the unique property of these 2D QDs, the optical limiting activity was studied using open aperture z-scan technique. TiS2 QDs exhibited appreciable nonlinear optical limiting, reaching 50% by a tapered and sharp absorption at input laser fluence of 4.24 GW/cm2.

中文翻译：

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回流预处理介导的超声处理：获得二维量子点的新通用途径

摘要 尽管基于二维 (2D) 材料的量子点 (QD) 在广泛的领域表现出迷人的特性和有前景的应用，但制备具有高产率的原子厚度二维 QD 的低成本和非繁琐方法仍然难以实现. 在此，我们首次展示了一种回流预处理介导的超声处理方法，以从它们的本体中生产一系列超薄二维量子点（例如，石墨烯、TiS2、MoS2、MoSe2、WSe2、NbS2、SnS2 和 h-BN QD）同行。溶剂分子在回流过程中被限制在层状材料的通道中，在浴超声处理过程中有助于二维片材的分层和断裂。由此产生的二维量子点表现出 2-7 nm 的均匀横向尺寸分布和 0.8-1 nm 的平均厚度，几乎与分层材料的单层厚度相同。为了证明这些 2D QD 的独特性质，使用开孔 z 扫描技术研究了光学限制活动。TiS2 QD 表现出明显的非线性光学限制，在 4.24 GW/cm2 的输入激光能量密度下通过锥形和锐吸收达到 50%。