Molecular orientation and site dependent charge transfer dynamics at PTCDA/TiO2(110) interface revealed by resonant photoemission spectroscopy

Abstract

Charge transfer dynamics across the interface of 3,4,9,10- perylenetetracarboxylic dianhydride (PTCDA) organic molecules and the reduced rutile TiO2 (110) 1 × 1 surface has been investigated using core-hole clock implementation of resonant photoemission spectroscopy (RPES). It is found that ultrafast charge transfer from PTCDA molecules to TiO2 substrate takes place on the time scale of 8-20 fs due to their strong electronic coupling. Moreover, the charge transfer time scale at the PTCDA/TiO2 (110) interface shows evident orientational dependence which varies with the molecular site owing to different electronic coupling strengths. © 2014 American Chemical Society.