Precise control over the photoluminescence（PL） of single quantum dots（QDs） is important for their practical applications. We show that the PL of individual Cd Se/Zn S core/shell QDs can be effectively enhanced and...Precise control over the photoluminescence（PL） of single quantum dots（QDs） is important for their practical applications. We show that the PL of individual Cd Se/Zn S core/shell QDs can be effectively enhanced and continuously modulated by electrochemically manipulating the electron transfer（ET） between the QDs and the attached redox-active ligands such as 2-mercaptoethanol（BME）. We found that i） the ET from BME to the QDs＇ surface trap states suppresses the blinking of the QDs, ii） the ET from the QDs＇ conduction band to the oxidization product results in dimmed PL when BME is oxidized,and iii） further oxidization of BME results in a significant PL brightening. The single particle measurements help us unveil the important features hidden in ensemble measurements and understand the underlying mechanism of the PL modulation.The results also suggest a simple yet efficient method to produce bright and non-blinking QDs and offer opportunities for further development of high resolution fluorescent bioimaging and nanodevices.展开更多
In this work, we investigated the energy transfer (EnT) and electron transfer (ET) processes as well as their relationship in the carbon quantum dots/rhodamine B (CQDs/RhB) including o-CQDs/Rh B and m-CQDs/RhB systems...In this work, we investigated the energy transfer (EnT) and electron transfer (ET) processes as well as their relationship in the carbon quantum dots/rhodamine B (CQDs/RhB) including o-CQDs/Rh B and m-CQDs/RhB systems by using photoluminescence spectroscopy in combination with steady-state and transient absorption spectroscopy. We found that the ET process is negligible in the o-CQDs/RhB system with an EnT efficiency as high as 73.2%,while it becomes pronounced in the m-CQDs/RhB system whose EnT efficiency is lower than 33.5%. Such an interplay of En T and ET processes revealed in the prototypical composite system consisting of carbon quantum dots and dye molecules would provide helpful insights for applications of relevance to exciton quenching.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10904164,61275192,and 11104328)
文摘Precise control over the photoluminescence（PL） of single quantum dots（QDs） is important for their practical applications. We show that the PL of individual Cd Se/Zn S core/shell QDs can be effectively enhanced and continuously modulated by electrochemically manipulating the electron transfer（ET） between the QDs and the attached redox-active ligands such as 2-mercaptoethanol（BME）. We found that i） the ET from BME to the QDs＇ surface trap states suppresses the blinking of the QDs, ii） the ET from the QDs＇ conduction band to the oxidization product results in dimmed PL when BME is oxidized,and iii） further oxidization of BME results in a significant PL brightening. The single particle measurements help us unveil the important features hidden in ensemble measurements and understand the underlying mechanism of the PL modulation.The results also suggest a simple yet efficient method to produce bright and non-blinking QDs and offer opportunities for further development of high resolution fluorescent bioimaging and nanodevices.
基金supported by the National Key Research and Development Program on Nano Science and Technology of MOST(No.2016YFA0200602 and No.2018YFA0208702)the National Natural Science Foundation of China(No.21573211 and No.21633007)the Anhui Initiative in Quantum Information Technologies(AHY090200)
文摘In this work, we investigated the energy transfer (EnT) and electron transfer (ET) processes as well as their relationship in the carbon quantum dots/rhodamine B (CQDs/RhB) including o-CQDs/Rh B and m-CQDs/RhB systems by using photoluminescence spectroscopy in combination with steady-state and transient absorption spectroscopy. We found that the ET process is negligible in the o-CQDs/RhB system with an EnT efficiency as high as 73.2%,while it becomes pronounced in the m-CQDs/RhB system whose EnT efficiency is lower than 33.5%. Such an interplay of En T and ET processes revealed in the prototypical composite system consisting of carbon quantum dots and dye molecules would provide helpful insights for applications of relevance to exciton quenching.
