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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

PL peak energy of (squares) dry colloidal CdSe NPs sample and (circles) in-liquid CdSe/ZnS NPs. The insert shows the same dependence for in-liquid NPs without monotonic part introduced in Equation 1.
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Figure 3: PL peak energy of (squares) dry colloidal CdSe NPs sample and (circles) in-liquid CdSe/ZnS NPs. The insert shows the same dependence for in-liquid NPs without monotonic part introduced in Equation 1.

Mentions: PL peak energy of in-liquid and dry colloidal CdSe/ZnS NPs in the temperature range of T = 240-290 K are shown on Figure 3. In-liquid CdSe/ZnS NPs are near the water freezing point. The dashed and solid lines are the best-fit curves to Varshni relation for dry and in-liquid NPs, respectively. It is clearly seen that PL peak energy of in-liquid NPs exhibits not only the monotonic temperature dependence similar to dry NPs sample but the N-type feature near the solvent phase transition. The PL peak energy increases by approximately 30 meV, from approximately 2.07 eV to approximately 2.1 eV, as the temperature changes from 260 to 270 K. Also, PL peak energy at low and high temperatures decreases at practically the same rate with increasing temperature.


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)

PL peak energy of (squares) dry colloidal CdSe NPs sample and (circles) in-liquid CdSe/ZnS NPs. The insert shows the same dependence for in-liquid NPs without monotonic part introduced in Equation 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: PL peak energy of (squares) dry colloidal CdSe NPs sample and (circles) in-liquid CdSe/ZnS NPs. The insert shows the same dependence for in-liquid NPs without monotonic part introduced in Equation 1.
Mentions: PL peak energy of in-liquid and dry colloidal CdSe/ZnS NPs in the temperature range of T = 240-290 K are shown on Figure 3. In-liquid CdSe/ZnS NPs are near the water freezing point. The dashed and solid lines are the best-fit curves to Varshni relation for dry and in-liquid NPs, respectively. It is clearly seen that PL peak energy of in-liquid NPs exhibits not only the monotonic temperature dependence similar to dry NPs sample but the N-type feature near the solvent phase transition. The PL peak energy increases by approximately 30 meV, from approximately 2.07 eV to approximately 2.1 eV, as the temperature changes from 260 to 270 K. Also, PL peak energy at low and high temperatures decreases at practically the same rate with increasing temperature.

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