Supramolecular ordering of PTCDA molecules : the key role of dispersion forces in an unusual transition from physisorbed into chemisorbed state

doi:10.1021/nn303546m

Supramolecular ordering of PTCDA molecules : the key ...

Bibliographic description

punktacja MNiSW [2012 A]: 45

title:	Supramolecular ordering of PTCDA molecules : the key role of dispersion forces in an unusual transition from physisorbed into chemisorbed state
author:	Godlewski Szymon , Tekiel Antoni, Piskorz Witold , Zasada Filip , Prauzner-Bechcicki Jakub , Sojka Zbigniew , Szymoński Marek
Journal title:	ACS Nano
volume:	6
issue:	10
date of publication:	2012
pages:	8536-8545
ISSN:	1936-0851
eISSN:	1936-086X
DOI:	10.1021/nn303546m
language:	English
Journal language:	English
abstract in english:	Adsorption and self-assembly of large pi-conjugated 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) molecules on rutile TiO2(110) surface have been investigated using a combination of high-resolution scanning tunneling microscopy (STM), low-energy electron diffraction, and density functional theory calculations with inclusion of Grimme treatment of the dispersion forces (DFT-D). Evolution of the STM images as a function of PTCDA coverage Is owed by transition of the adsorption mode from physisorbed single adspecies and meandering stripes into spontaneously ordered chemisorbed molecular assemblies. This change in the adsorption fashion is accompanied by significant bending of the intrinsically flat, yet elastic, PTCDA molecule, which allows for strong electronic coupling of the dye adspecies with the TiO2 substrate. Extensive DFT-D modeling has revealed that adsorption is controlled by interfacial and intermolecular dispersion forces playing a dominant role in the adsorption of single PTCDA species, their self-organization into the meandering stripes, and at the monolayer coverage acting collectively to surmount the chemisorption energy barrier associated with the molecule bending. Analysis of the resulting density of states has revealed that alignment of the energy levels and strong electronic coupling at the PTCDA/TiO2 interface are beneficial for dye sensitization purposes
keywords in other languages:	supramolecular ordering, titanium dioxide, TiO2, PTCDA, dye sensitization, photovoltaics, STM, DFT-D, van der Waals, semi-empirical dispersion, adsorption, DOS, surface functionalization
number of pulisher's sheets:	1
affiliation:	Wydział Fizyki, Astronomii i Informatyki Stosowanej : Instytut Fizyki im. Mariana Smoluchowskiego, Wydział Chemii : Zakład Chemii Nieorganicznej
type:	journal article
subtype:	academic paper