Ultrafast Coherent Electron-Hole Separation Dynamics in a Fullerene Derivative.

Academic Article

Abstract

  • The use of fullerene derivatives as electron donors in bulk heterojunctions is a promising development in the search for efficient energy conversion in hybrid solar cells. A long-lived photoexcited electron-hole pair will give rise to increased efficiency in photoenergy conversion. One way to prevent fast electron-hole recombination is to engineer fullerene derivatives that exhibit intrinsic electron-hole separation through accessible charge-transfer excited states. In this letter, the dynamics of photoexcited electron-hole pairs in a C60 derivative is studied using the real-time time-dependent density functional theory. Although the charge-transfer excited state is not directly accessible from the ground state, intrinsic coherent electron-hole separation is observed following photoexcition as a result of direct coupling between excited states. Ultrafast charge-transfer dynamics is the dominant phenomenon in <60 fs after visible photoexcitation. This work provides insights into the characteristics of ultrafast dynamics in photoexcited fullerene derivatives, and aids in the rational design of efficient solar cells.
  • Authors

  • Chapman, Craig
  • Liang, Wenkel
  • Li, Xiaosong
  • Status

    Publication Date

  • May 19, 2011
  • Published In

    Keywords

  • TDDFT
  • charge transfer
  • electron−hole dynamics
  • fullerene
  • Digital Object Identifier (doi)

    Pubmed Id

  • 26295324
  • Start Page

  • 1189
  • End Page

  • 1192
  • Volume

  • 2
  • Issue

  • 10