光致发光
荧光
猝灭(荧光)
材料科学
水溶液
量子点
纳米技术
相变
化学
光化学
分析化学(期刊)
化学物理
碳纤维
光电子学
物理化学
有机化学
复合材料
物理
复合数
量子力学
作者
Sergii Kalytchuk,Lukáš Zdražil,Zdeňěk Baďura,Miroslav Medveď,Michal Langer,Markéta Paloncýová,Giorgio Zoppellaro,Stephen V. Kershaw,Andrey L. Rogach,Michal Otyepka,Radek Zbořil
出处
期刊:ACS Nano
[American Chemical Society]
日期:2021-03-16
卷期号:15 (4): 6582-6593
被引量:29
标识
DOI:10.1021/acsnano.0c09781
摘要
Highly fluorescent carbon nanoparticles called carbon dots (CDs) have been the focus of intense research due to their simple chemical synthesis, nontoxic nature, and broad application potential including optoelectronics, photocatalysis, biomedicine, and energy-related technologies. Although a detailed elucidation of the mechanism of their photoluminescence (PL) remains an unmet challenge, the CDs exhibit robust, reproducible, and environment-sensitive PL signals, enabling us to monitor selected chemical phenomena including phase transitions or detection of ultralow concentrations of molecular species in solution. Herein, we report the PL turn-off/on behavior of aqueous CDs allowing the reversible monitoring of the water–ice phase transition. The bright PL attributable to molecular fluorophores present on the CD surface was quenched by changing the liquid aqueous environment to solid phase (ice). Based on light-induced electron paramagnetic resonance (LEPR) measurements and density functional theory (DFT) calculations, the proposed kinetic model assuming the presence of charge-separated trap states rationalized the observed sensitivity of PL lifetimes to the environment. Importantly, the PL quenching induced by freezing could be suppressed by adding a small amount of alcohols. This was attributed to a high tendency of alcohol to increase its concentration at the CD/solvent interface, as revealed by all-atom molecular dynamics simulations. Based on this behavior, a fluorescence “turn-on” alcohol sensor for exhaled breath condensate (EBC) analysis has been developed. This provided an easy method to detect alcohols among other common interferents in EBC with a low detection limit (100 ppm), which has a potential to become an inexpensive and noninvasive clinically useful diagnostic tool for early stage lung cancer screening.
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