Ultrafast Trap State-Mediated Electron Transfer for Quantum Dot Redox Sensing
Ultrafast Trap State-Mediated Electron Transfer for Quantum Dot Redox Sensing
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DOI：
10.1021/acs.jpcc.8b02551
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发表时间：
2018-04
影响因子：
3.7
通讯作者：
A. Harvie;Charles T Smith;Ruben Ahumada-Lazo;L. Jeuken;M. Califano;R. Bon;S. Hardman;D. Binks;K. Critchley
中科院分区：
文献类型：
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作者：
A. Harvie;Charles T Smith;Ruben Ahumada-Lazo;L. Jeuken;M. Califano;R. Bon;S. Hardman;D. Binks;K. Critchley
与电子受体配体缀合的量子点 (QD) 可用作从化学检测到生物成像等应用的氧化还原传感器。我们的目标是提高这些氧化还原传感量子点共轭物的有效性，这取决于初始电荷分离和重组的竞争机制，包括发光和电子转移到共轭氧化还原分子。在本研究中，超快激光测量用于研究 CdTe/CdS 核/壳 QD 的激发态动力学，其中醌/醌受体 (Q2NS) 配体附着在表面（每个 QD 最多 40 个）。详细分析以及系统的计算模型显示了多种电子转移途径，并确定了从表面电子陷阱状态到醌配体的超快电子转移（2-8 ps）。我们认为这会带来高的、依赖于氧化还原的淬灭效率（表面平均有 10 个醌/醌醇，淬灭效率为 98.7%）。由于只需要少量的氧化还原配体，...
Quantum dots (QDs) conjugated to electron acceptor ligands are useful as redox sensors in applications ranging from chemical detection to bioimaging. We aimed to improve effectiveness of these redox-sensing QD conjugates, which depends on the initial charge separation and on the competing mechanisms of recombination, including luminescence and electron transfer to the conjugated redox molecules. In this study, ultrafast laser measurements were used to study the excited state dynamics in CdTe/CdS core/shell QDs with quinone/quinol acceptor (Q2NS) ligands attached to the surface (up to 40 per QD). Detailed analysis, along with computational modeling of the system, showed multiple electron-transfer pathways and identified an ultrafast electron transfer from a surface electron trap state to the quinone ligands (2–8 ps). We propose that this leads to high, redox-dependent, quenching efficiencies (98.7% with an average of 10 quinone/quinols on the surface). As only low populations of redox ligands are required,...