Enhancing photo-induced ultrafast charge transfer across heterojunctions of CdS and laser-sintered TiO2 nanocrystals

Bryan T. Spann, S. Venkataprasad Bhat, Qiong Nian, Kelly M. Rickey, Gary J. Cheng, Xiulin Ruan, Xianfan Xu

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Enhancing the charge transfer process in nanocrystal sensitized solar cells is vital for the improvement of their performance. In this work we show a means of increasing photo-induced ultrafast charge transfer in successive ionic layer adsorption and reaction (SILAR) CdS-TiO2 nanocrystal heterojunctions using pulsed laser sintering of TiO2 nanocrystals. The enhanced charge transfer was attributed to both morphological and phase transformations. At sufficiently high laser fluences, volumetrically larger porous networks of the metal oxide were obtained, thus increasing the density of electron accepting states. Laser sintering also resulted in varying degrees of anatase to rutile phase transformation of the TiO2, producing thermodynamically more favorable conditions for charge transfer by increasing the change in free energy between the CdS donor and TiO2 acceptor states. Finally, we report aspects of apparent hot electron transfer as a result of the SILAR process which allows CdS to be directly adsorbed to the TiO2 surface. This journal is

Original languageEnglish (US)
Pages (from-to)10669-10678
Number of pages10
JournalPhysical Chemistry Chemical Physics
Volume16
Issue number22
DOIs
StatePublished - Jun 14 2014
Externally publishedYes

Fingerprint

Nanocrystals
Heterojunctions
Charge transfer
heterojunctions
nanocrystals
charge transfer
Lasers
lasers
phase transformations
sintering
Sintering
Phase transitions
Adsorption
Electronic density of states
adsorption
Hot electrons
electron states
Pulsed lasers
hot electrons
anatase

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Enhancing photo-induced ultrafast charge transfer across heterojunctions of CdS and laser-sintered TiO2 nanocrystals. / Spann, Bryan T.; Bhat, S. Venkataprasad; Nian, Qiong; Rickey, Kelly M.; Cheng, Gary J.; Ruan, Xiulin; Xu, Xianfan.

In: Physical Chemistry Chemical Physics, Vol. 16, No. 22, 14.06.2014, p. 10669-10678.

Research output: Contribution to journalArticle

Spann, Bryan T. ; Bhat, S. Venkataprasad ; Nian, Qiong ; Rickey, Kelly M. ; Cheng, Gary J. ; Ruan, Xiulin ; Xu, Xianfan. / Enhancing photo-induced ultrafast charge transfer across heterojunctions of CdS and laser-sintered TiO2 nanocrystals. In: Physical Chemistry Chemical Physics. 2014 ; Vol. 16, No. 22. pp. 10669-10678.
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