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

Safna Ravindi Padmaperuma, Maning Liu, Ryosuke Nakamura, Yasuhiro Tachibana

Research output: Contribution to journalArticlepeer-review

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 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.

Original languageEnglish
Pages (from-to)271-278
Number of pages8
JournalJournal of Photopolymer Science and Technology
Volume34
Issue number3
DOIs
Publication statusPublished - 2021
Externally publishedYes

Subject classification (UKÄ)

  • Physical Chemistry

Free keywords

  • CdS quantum dot sensitized TiO
  • Charge recombination
  • Electron injection
  • Photocurrent generation efficiency
  • Quantum dot size
  • Solar cells

Fingerprint

Dive into the research topics of 'Photoinduced Charge Carrier Dynamics of Metal Chalcogenide Semiconductor Quantum Dot Sensitized TiO2 Film for Photovoltaic Application'. Together they form a unique fingerprint.

Cite this