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Photoluminescence response of colloidal quantum dots on VO2 film across metal to insulator transition.

Kuznetsov SN, Cheremisin AB, Stefanovich GB - Nanoscale Res Lett (2014)

Bottom Line: The supporting reflectance data point out that photoluminescence response mimics a reflectance change in VO2 across metal to insulator transition.Time-resolved photoluminescence study did not reveal any significant change of luminescence lifetime of deposited quantum dots under metal to insulator transition.It is a strong argument in favor of the proposed explanation based on the reflectance data. 71.30. + h; 73.21.La; 78.47.jd.

View Article: PubMed Central - HTML - PubMed

Affiliation: Physico-Technical Department, Petrozavodsk State University, Lenin av. 33, 185910 Petrozavodsk, Russian Federation.

ABSTRACT

Unlabelled: We have proposed a method to probe metal to insulator transition in VO2 measuring photoluminescence response of colloidal quantum dots deposited on the VO2 film. In addition to linear luminescence intensity decrease with temperature that is well known for quantum dots, temperature ranges with enhanced photoluminescence changes have been found during phase transition in the oxide. Corresponding temperature derived from luminescence dependence on temperature closely correlates with that from resistance measurement during heating. The supporting reflectance data point out that photoluminescence response mimics a reflectance change in VO2 across metal to insulator transition. Time-resolved photoluminescence study did not reveal any significant change of luminescence lifetime of deposited quantum dots under metal to insulator transition. It is a strong argument in favor of the proposed explanation based on the reflectance data.

Pacs: 71.30. + h; 73.21.La; 78.47.jd.

No MeSH data available.


Related in: MedlinePlus

Photoluminescence response of QDs on dielectric substrate. (a) Temperature dependence of PL peak position (points) and corresponding Varshni fit (line). (b) PL spectra for different temperatures.
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Figure 3: Photoluminescence response of QDs on dielectric substrate. (a) Temperature dependence of PL peak position (points) and corresponding Varshni fit (line). (b) PL spectra for different temperatures.

Mentions: Before presenting the main results, we recall the well-known temperature effect on the semiconductor band gap - its narrowing with temperature increase. Concerning CdSe/ZnS QDs, this effect becomes apparent as red shift of PL band [8]. We confirm these observations for QDs deposited on dielectric substrate (namely, the above mentioned sitall). Figure 3a shows temperature dependence of PL peak energy (points) and corresponding fit to empirical Varshni formula [8]. Figure 3b illustrates measured PL spectra of QDs for different temperatures. As can be seen, QDs spectra are characterized by near-Gaussian shape with narrow emission band width of approximately 0.1 eV at half maximum. Note that we will use the term ‘PL intensity’ defined as an integral over whole emission band (so-called integrated PL). Moreover, PL intensity linear decrease is observed with temperature when QDs are placed at the dielectric substrate. This case is shown for normalized PL intensity in Figure 4a, curve 1.


Photoluminescence response of colloidal quantum dots on VO2 film across metal to insulator transition.

Kuznetsov SN, Cheremisin AB, Stefanovich GB - Nanoscale Res Lett (2014)

Photoluminescence response of QDs on dielectric substrate. (a) Temperature dependence of PL peak position (points) and corresponding Varshni fit (line). (b) PL spectra for different temperatures.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4232974&req=5

Figure 3: Photoluminescence response of QDs on dielectric substrate. (a) Temperature dependence of PL peak position (points) and corresponding Varshni fit (line). (b) PL spectra for different temperatures.
Mentions: Before presenting the main results, we recall the well-known temperature effect on the semiconductor band gap - its narrowing with temperature increase. Concerning CdSe/ZnS QDs, this effect becomes apparent as red shift of PL band [8]. We confirm these observations for QDs deposited on dielectric substrate (namely, the above mentioned sitall). Figure 3a shows temperature dependence of PL peak energy (points) and corresponding fit to empirical Varshni formula [8]. Figure 3b illustrates measured PL spectra of QDs for different temperatures. As can be seen, QDs spectra are characterized by near-Gaussian shape with narrow emission band width of approximately 0.1 eV at half maximum. Note that we will use the term ‘PL intensity’ defined as an integral over whole emission band (so-called integrated PL). Moreover, PL intensity linear decrease is observed with temperature when QDs are placed at the dielectric substrate. This case is shown for normalized PL intensity in Figure 4a, curve 1.

Bottom Line: The supporting reflectance data point out that photoluminescence response mimics a reflectance change in VO2 across metal to insulator transition.Time-resolved photoluminescence study did not reveal any significant change of luminescence lifetime of deposited quantum dots under metal to insulator transition.It is a strong argument in favor of the proposed explanation based on the reflectance data. 71.30. + h; 73.21.La; 78.47.jd.

View Article: PubMed Central - HTML - PubMed

Affiliation: Physico-Technical Department, Petrozavodsk State University, Lenin av. 33, 185910 Petrozavodsk, Russian Federation.

ABSTRACT

Unlabelled: We have proposed a method to probe metal to insulator transition in VO2 measuring photoluminescence response of colloidal quantum dots deposited on the VO2 film. In addition to linear luminescence intensity decrease with temperature that is well known for quantum dots, temperature ranges with enhanced photoluminescence changes have been found during phase transition in the oxide. Corresponding temperature derived from luminescence dependence on temperature closely correlates with that from resistance measurement during heating. The supporting reflectance data point out that photoluminescence response mimics a reflectance change in VO2 across metal to insulator transition. Time-resolved photoluminescence study did not reveal any significant change of luminescence lifetime of deposited quantum dots under metal to insulator transition. It is a strong argument in favor of the proposed explanation based on the reflectance data.

Pacs: 71.30. + h; 73.21.La; 78.47.jd.

No MeSH data available.


Related in: MedlinePlus