Abstract
Solvent effects on luminescence in nanocolloids are typically related to changes in the dielectric constant around the light-emitting species, but they can have a completely different nature in complex dynamic nanoscale assemblies. Hybrid superstructures were assembled from Au nanoparticles (NPs) and CdTe nanowires (NWs) via poly(ethylene glycol) (PEG) bridges and provide the first example of solvent-responsive dynamic nanoscale assemblies from NWs. The photoluminescence (PL) intensity of the CdTe NWs was found to be dependent on the hydrophilic/hydrophobic balance of the solvent (water, methanol, ethanol, and 2-propanol) surrounding the superstructure and displayed slow equilibration kinetics. PL gradually decreased over a period of 2000 s by ca. 50% for ethanol and ca. 70% for 2-propanol, whereas it remained constant for water and methanol. This phenomenon was attributed to the solvent dependence of the radius of gyration (RF) of the PEG bridges between the NPs and NWs, which swells in ethanol and 2-propanol. The average distance between the NPs and NWs affects the plasmon-exciton interactions responsible for optical processes in the superstructure, and expansion results in a decrease of the luminescence enhancement of Cd Te by Au NPs. Theoretical modeling was carried out to confirm the mechanism of the solvent effect. Exciton-plasmon resonance was described as a combination of two components: field enhancement and energy transfer. Although carrying some limitations and being inherently approximate, this approach was able to describe the distance dependence of the PL intensity of NP-NW system well. The suggested theoretical model expands the understanding of plasmon-exciton electronic systems and can be applied to many semiconductor-metal superstructures.
| Original language | English |
|---|---|
| Pages (from-to) | 1404-1410 |
| Number of pages | 7 |
| Journal | Journal of Physical Chemistry C |
| Volume | 114 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - Jan 28 2010 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Electronic, Optical and Magnetic Materials
- Surfaces, Coatings and Films
- Energy(all)
Cite this
Solvent effect in dynamic superstructures from au nanoparticles and cdte nanowires : Experimental observation and theoretical description. / Lee, Jaebeom; Orazbayev, Azamat; Govorov, Alexander O.; Kotov, Nicholas A.
In: Journal of Physical Chemistry C, Vol. 114, No. 3, 28.01.2010, p. 1404-1410.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Solvent effect in dynamic superstructures from au nanoparticles and cdte nanowires
T2 - Experimental observation and theoretical description
AU - Lee, Jaebeom
AU - Orazbayev, Azamat
AU - Govorov, Alexander O.
AU - Kotov, Nicholas A.
PY - 2010/1/28
Y1 - 2010/1/28
N2 - Solvent effects on luminescence in nanocolloids are typically related to changes in the dielectric constant around the light-emitting species, but they can have a completely different nature in complex dynamic nanoscale assemblies. Hybrid superstructures were assembled from Au nanoparticles (NPs) and CdTe nanowires (NWs) via poly(ethylene glycol) (PEG) bridges and provide the first example of solvent-responsive dynamic nanoscale assemblies from NWs. The photoluminescence (PL) intensity of the CdTe NWs was found to be dependent on the hydrophilic/hydrophobic balance of the solvent (water, methanol, ethanol, and 2-propanol) surrounding the superstructure and displayed slow equilibration kinetics. PL gradually decreased over a period of 2000 s by ca. 50% for ethanol and ca. 70% for 2-propanol, whereas it remained constant for water and methanol. This phenomenon was attributed to the solvent dependence of the radius of gyration (RF) of the PEG bridges between the NPs and NWs, which swells in ethanol and 2-propanol. The average distance between the NPs and NWs affects the plasmon-exciton interactions responsible for optical processes in the superstructure, and expansion results in a decrease of the luminescence enhancement of Cd Te by Au NPs. Theoretical modeling was carried out to confirm the mechanism of the solvent effect. Exciton-plasmon resonance was described as a combination of two components: field enhancement and energy transfer. Although carrying some limitations and being inherently approximate, this approach was able to describe the distance dependence of the PL intensity of NP-NW system well. The suggested theoretical model expands the understanding of plasmon-exciton electronic systems and can be applied to many semiconductor-metal superstructures.
AB - Solvent effects on luminescence in nanocolloids are typically related to changes in the dielectric constant around the light-emitting species, but they can have a completely different nature in complex dynamic nanoscale assemblies. Hybrid superstructures were assembled from Au nanoparticles (NPs) and CdTe nanowires (NWs) via poly(ethylene glycol) (PEG) bridges and provide the first example of solvent-responsive dynamic nanoscale assemblies from NWs. The photoluminescence (PL) intensity of the CdTe NWs was found to be dependent on the hydrophilic/hydrophobic balance of the solvent (water, methanol, ethanol, and 2-propanol) surrounding the superstructure and displayed slow equilibration kinetics. PL gradually decreased over a period of 2000 s by ca. 50% for ethanol and ca. 70% for 2-propanol, whereas it remained constant for water and methanol. This phenomenon was attributed to the solvent dependence of the radius of gyration (RF) of the PEG bridges between the NPs and NWs, which swells in ethanol and 2-propanol. The average distance between the NPs and NWs affects the plasmon-exciton interactions responsible for optical processes in the superstructure, and expansion results in a decrease of the luminescence enhancement of Cd Te by Au NPs. Theoretical modeling was carried out to confirm the mechanism of the solvent effect. Exciton-plasmon resonance was described as a combination of two components: field enhancement and energy transfer. Although carrying some limitations and being inherently approximate, this approach was able to describe the distance dependence of the PL intensity of NP-NW system well. The suggested theoretical model expands the understanding of plasmon-exciton electronic systems and can be applied to many semiconductor-metal superstructures.
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U2 - 10.1021/jp809780m
DO - 10.1021/jp809780m
M3 - Article
VL - 114
SP - 1404
EP - 1410
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 3
ER -