| Autor: |
Cao W; School of Photovoltaic and Renewable Energy Engineering, UNSW Sydney, Sydney, NSW 2052, Australia. z3169210@unsw.edu.au., Yuan L, Patterson R, Wen X, Tapping PC, Kee T, Veetil BP, Zhang P, Zhang Z, Zhang Q, Reece P, Bremner S, Shrestha S, Conibeer G, Huang S |
| Jazyk: |
angličtina |
| Zdroj: |
Nanoscale [Nanoscale] 2017 Nov 09; Vol. 9 (43), pp. 17133-17142. |
| DOI: |
10.1039/c7nr05247b |
| Abstrakt: |
The carrier dynamics of lead sulphide quantum dot (PbS QD) drop cast films and closely packed ordered Langmuir-Blodgett films are studied with ultra-fast femtosecond transient absorption spectroscopy. The photo-induced carrier temperature is extracted from transient absorption spectra and monitored as a function of time delay. The cooling dynamics of carriers in PbS QDs suggest a reduction of the carrier energy loss rate at longer time delays through the retardation of the longitudinal optical (LO) phonon decay due to partial heating of acoustic phonon modes. A slowed hot carrier cooling time up to 116 ps is observed in the drop cast film. A faster cooling rate was also observed in the highly compact Langmuir-Blodgett film due to the enhanced carrier-LO phonon coupling strength arising from the Coulombic interaction in neighboring QDs, which is verified by temperature dependent steady state PL measurements. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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