TiO2 nanowire sensitized by natural dyes for solar cell applications

ORAL

Abstract

We investigate the electronic coupling between a semiconductor TiO$_2$ nanowire and a natural dye sensitizer based on time-dependent first-principles calculations. The model dye molecule, cyanidin is found to dissociate into the quinonoidal form upon adsorption, rendering its highest occupied molecular orbitals (HOMO) located in the middle of TiO$_2$ bandgap and its lowest-unoccupied molecular orbital (LUMO) at the bottom of TiO$_2$ conduction band. The visible light absorption is greatly enhanced with two prominent peaks at 460 nm and 650 nm. The excited electrons are injected into the TiO$_2$ conduction within a ultrafast timescale of $<$50 fs, with negligible non-radiative energy dissipation and recombination.

*This work is supported in part by DOE CMSNGrant DE-FG02-05ER46226 and Harvard University Center for the Environment.

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Authors

  • Sheng Meng

    • Harvard University

  • Jun Ren

    • Harvard University
    • Physics Department and School of Engineering and Applied Sciences, Harvard University

  • Efthimios Kaxiras

    • Harvard University
    • Department of Physics and School of Engineering and Applied Sciences, Harvard University
    • Department of Physics and School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA