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Luminescence of colloidal CdSe/ZnS nanoparticles: high sensitivity to solvent phase transitions.

Antipov A, Bell M, Yasar M, Mitin V, Scharmach W, Swihart M, Verevkin A, Sergeev A - Nanoscale Res Lett (2011)

Bottom Line: We investigate nanosecond photoluminescence processes in colloidal core/shell CdSe/ZnS nanoparticles dissolved in water and found strong sensitivity of luminescence to the solvent state.First of all, the luminescence intensity substantially (approximately 50%) increases near the transition.The observed effects are associated with the reconstruction of ligands near the ice/water phase transition.

View Article: PubMed Central - HTML - PubMed

Affiliation: Electrical Engineering Department, University at Buffalo, Buffalo, NY 14260, USA. vmitin@buffalo.edu.

ABSTRACT
We investigate nanosecond photoluminescence processes in colloidal core/shell CdSe/ZnS nanoparticles dissolved in water and found strong sensitivity of luminescence to the solvent state. Several pronounced changes have been observed in the narrow temperature interval near the water melting point. First of all, the luminescence intensity substantially (approximately 50%) increases near the transition. In a large temperature scale, the energy peak of the photoluminescence decreases with temperature due to temperature dependence of the energy gap. Near the melting point, the peak shows N-type dependence with the maximal changes of approximately 30 meV. The line width increases with temperature and also shows N-type dependence near the melting point. The observed effects are associated with the reconstruction of ligands near the ice/water phase transition.

No MeSH data available.


Related in: MedlinePlus

Exciton lifetime of in-liquid CdSe/ZnS NPs near the water freezing point. The insert shows the fit (solid line) to the fast component of PL decay curve.
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Figure 5: Exciton lifetime of in-liquid CdSe/ZnS NPs near the water freezing point. The insert shows the fit (solid line) to the fast component of PL decay curve.

Mentions: We also investigate the temperature dependence of exciton lifetime of in-liquid CdSe/ZnS NPs near the water freezing point. Time-resolved measurements are performed using the time-correlated single-photon counting system, PicoHarp 300. PL decay curves are analyzed by multiexponential fitting. As it is shown in the insert of Figure 5, PL response consists of two (fast and slow) exponential components. The fast component of PL decay at T = 240-290 K is shown in Figure 5. It undergoes the shift by approximately 200 ps, from 150 to 350 ps, within a temperature range of 260-270 K. The fast component decreases in the temperature range T = 240-260 K and slowly increases at T = 260-290 K. The slow component of PL decay curve does not exhibit any changes in the temperature range T = 240-290 K and stays the same for approximately 10 ns. The experimental investigations of dry NPs show that there are no changes in exciton lifetime as for the slow component and for the fast component of PL decay curve within the temperature range T = 240-290 K. New N-type feature that we report here correlates very well with the behavior of exciton lifetime of in-liquid NPs near the water freezing point.


Luminescence of colloidal CdSe/ZnS nanoparticles: high sensitivity to solvent phase transitions.

Antipov A, Bell M, Yasar M, Mitin V, Scharmach W, Swihart M, Verevkin A, Sergeev A - Nanoscale Res Lett (2011)

Exciton lifetime of in-liquid CdSe/ZnS NPs near the water freezing point. The insert shows the fit (solid line) to the fast component of PL decay curve.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211190&req=5

Figure 5: Exciton lifetime of in-liquid CdSe/ZnS NPs near the water freezing point. The insert shows the fit (solid line) to the fast component of PL decay curve.
Mentions: We also investigate the temperature dependence of exciton lifetime of in-liquid CdSe/ZnS NPs near the water freezing point. Time-resolved measurements are performed using the time-correlated single-photon counting system, PicoHarp 300. PL decay curves are analyzed by multiexponential fitting. As it is shown in the insert of Figure 5, PL response consists of two (fast and slow) exponential components. The fast component of PL decay at T = 240-290 K is shown in Figure 5. It undergoes the shift by approximately 200 ps, from 150 to 350 ps, within a temperature range of 260-270 K. The fast component decreases in the temperature range T = 240-260 K and slowly increases at T = 260-290 K. The slow component of PL decay curve does not exhibit any changes in the temperature range T = 240-290 K and stays the same for approximately 10 ns. The experimental investigations of dry NPs show that there are no changes in exciton lifetime as for the slow component and for the fast component of PL decay curve within the temperature range T = 240-290 K. New N-type feature that we report here correlates very well with the behavior of exciton lifetime of in-liquid NPs near the water freezing point.

Bottom Line: We investigate nanosecond photoluminescence processes in colloidal core/shell CdSe/ZnS nanoparticles dissolved in water and found strong sensitivity of luminescence to the solvent state.First of all, the luminescence intensity substantially (approximately 50%) increases near the transition.The observed effects are associated with the reconstruction of ligands near the ice/water phase transition.

View Article: PubMed Central - HTML - PubMed

Affiliation: Electrical Engineering Department, University at Buffalo, Buffalo, NY 14260, USA. vmitin@buffalo.edu.

ABSTRACT
We investigate nanosecond photoluminescence processes in colloidal core/shell CdSe/ZnS nanoparticles dissolved in water and found strong sensitivity of luminescence to the solvent state. Several pronounced changes have been observed in the narrow temperature interval near the water melting point. First of all, the luminescence intensity substantially (approximately 50%) increases near the transition. In a large temperature scale, the energy peak of the photoluminescence decreases with temperature due to temperature dependence of the energy gap. Near the melting point, the peak shows N-type dependence with the maximal changes of approximately 30 meV. The line width increases with temperature and also shows N-type dependence near the melting point. The observed effects are associated with the reconstruction of ligands near the ice/water phase transition.

No MeSH data available.


Related in: MedlinePlus