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Photoinduced Charge Carrier Dynamics of Metal Chalcogenide Semiconductor Quantum Dot Sensitized TiO2 Film for Photovoltaic Application

Padmaperuma, Safna Ravindi ; Liu, Maning LU orcid ; Nakamura, Ryosuke and Tachibana, Yasuhiro (2021) In Journal of Photopolymer Science and Technology 34(3). p.271-278
Abstract

Semiconductor quantum dot (QD) sensitization is one of the most attractive structures to employ QDs for photovoltaic application. The function of QD sensitized solar cells (QDSSC) is controlled by the interfacial charge transfer dynamics. Here we employ transient absorption spectroscopy (TAS) to assess charge transfer dynamics at CdS QD/TiO2 interface, and correlate their dynamics with their solar cell performance. An electron injection occurs from CdS QD conduction band to TiO2 on ultrafast time scales, and the time constant decreases from ~10 ps to 1 ps, as the QD size decreases from 4 nm to 1.6 nm. Also, the charge recombination lifetime at the QD/TiO2 interface increases, as the QD size increases. An... (More)

Semiconductor quantum dot (QD) sensitization is one of the most attractive structures to employ QDs for photovoltaic application. The function of QD sensitized solar cells (QDSSC) is controlled by the interfacial charge transfer dynamics. Here we employ transient absorption spectroscopy (TAS) to assess charge transfer dynamics at CdS QD/TiO2 interface, and correlate their dynamics with their solar cell performance. An electron injection occurs from CdS QD conduction band to TiO2 on ultrafast time scales, and the time constant decreases from ~10 ps to 1 ps, as the QD size decreases from 4 nm to 1.6 nm. Also, the charge recombination lifetime at the QD/TiO2 interface increases, as the QD size increases. An absorbed photon to current conversion efficiency (APCE) of the QDSSC increases, as the QD size increases. Therefore, we conclude that the APCE of the CdS QDSSC is controlled by the interfacial charge recombination dynamics competing with dynamics of the hole transfer from the QD valence band to the reduced electrolyte. The optimum CdS QD size is close to or larger than 4 nm, as long as the light harvesting efficiency of the CdS QD sensitized film is sufficiently high.

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author
; ; and
publishing date
type
Contribution to journal
publication status
published
subject
keywords
CdS quantum dot sensitized TiO, Charge recombination, Electron injection, Photocurrent generation efficiency, Quantum dot size, Solar cells
in
Journal of Photopolymer Science and Technology
volume
34
issue
3
pages
8 pages
publisher
Tokai University
external identifiers
  • scopus:85123783388
ISSN
0914-9244
DOI
10.2494/PHOTOPOLYMER.34.271
language
English
LU publication?
no
id
938f661d-52e0-4d9c-b1ed-2fb5099c2322
date added to LUP
2023-08-24 12:20:54
date last changed
2023-08-25 13:08:43
@article{938f661d-52e0-4d9c-b1ed-2fb5099c2322,
  abstract     = {{<p>Semiconductor quantum dot (QD) sensitization is one of the most attractive structures to employ QDs for photovoltaic application. The function of QD sensitized solar cells (QDSSC) is controlled by the interfacial charge transfer dynamics. Here we employ transient absorption spectroscopy (TAS) to assess charge transfer dynamics at CdS QD/TiO<sub>2</sub> interface, and correlate their dynamics with their solar cell performance. An electron injection occurs from CdS QD conduction band to TiO<sub>2</sub> on ultrafast time scales, and the time constant decreases from ~10 ps to 1 ps, as the QD size decreases from 4 nm to 1.6 nm. Also, the charge recombination lifetime at the QD/TiO<sub>2</sub> interface increases, as the QD size increases. An absorbed photon to current conversion efficiency (APCE) of the QDSSC increases, as the QD size increases. Therefore, we conclude that the APCE of the CdS QDSSC is controlled by the interfacial charge recombination dynamics competing with dynamics of the hole transfer from the QD valence band to the reduced electrolyte. The optimum CdS QD size is close to or larger than 4 nm, as long as the light harvesting efficiency of the CdS QD sensitized film is sufficiently high.</p>}},
  author       = {{Padmaperuma, Safna Ravindi and Liu, Maning and Nakamura, Ryosuke and Tachibana, Yasuhiro}},
  issn         = {{0914-9244}},
  keywords     = {{CdS quantum dot sensitized TiO; Charge recombination; Electron injection; Photocurrent generation efficiency; Quantum dot size; Solar cells}},
  language     = {{eng}},
  number       = {{3}},
  pages        = {{271--278}},
  publisher    = {{Tokai University}},
  series       = {{Journal of Photopolymer Science and Technology}},
  title        = {{Photoinduced Charge Carrier Dynamics of Metal Chalcogenide Semiconductor Quantum Dot Sensitized TiO<sub>2</sub> Film for Photovoltaic Application}},
  url          = {{http://dx.doi.org/10.2494/PHOTOPOLYMER.34.271}},
  doi          = {{10.2494/PHOTOPOLYMER.34.271}},
  volume       = {{34}},
  year         = {{2021}},
}