Optical-Gain-based Sensing Using Inorganic-Ligand-Passivated Colloidal Quantum Dots
Optical-Gain-based Sensing Using Inorganic-Ligand-Passivated Colloidal Quantum Dots
复制标题
使用无机配体钝化胶体量子点进行基于光学增益的传感
DOI：
10.1021/acs.nanolett.1c02547
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发表时间：
2021
期刊：
影响因子：
10.8
通讯作者：
Du Jiangfeng
中科院分区：
文献类型：
--
作者：
Chen Weiguo;Lu Xuechun;Fan Fengjia;Du Jiangfeng
胶体量子点具有极大的比表面积，是一种潜在的高性能传感材料。然而，以前的传感工作，使用它们的自发辐射遭受低灵敏度。扩增过程的缺乏和长链有机配体的空间位阻的存在是两个可能的原因。在这里，我们建议这两个问题可以通过使用由短链无机配体覆盖的胶体量子点的放大自发辐射来规避。为了验证这一概念，我们进行了湿度传感，并观察到灵敏度提高了2.31倍。同时，我们发现在高湿度环境下，放大自发辐射阈值功率降低了34%。在我们的瞬态吸收测量的基础上，我们将这些观测结果归因于超快亚皮秒捕获过程的缓解，这是由水分子的吸收实现的。
Thanks to their extremely large surface-to-volume ratio, colloidal quantum dots are potential high-performance sensing materials. However, previous sensing works using their spontaneous emission suffer from low sensitivities. The absence of an amplification process and the presence of the steric hindrance of long-chain organic ligands are two possible causations. Herein we propose that these two issues can be circumvented by using the amplified spontaneous emission of colloidal quantum dots capped by short-chain inorganic ligands. To exemplify this concept, we performed humidity sensing and observed a ∼31 times enhancement in sensitivity. Meanwhile, we found that the amplified spontaneous emission threshold power was reduced by 34% in a high humidity environment. On the basis of our transient absorption measurements, we attribute these observations to the mitigation of ultrafast subpicosecond trapping processes, which are enabled by the absorption of water molecules.