How mobile are dye adsorbates and acetonitrile molecules on the surface of TiO₂ nanoparticles? A quasi-elastic neutron scattering study.

ABSTRACT: Motions of molecules adsorbed to surfaces may control the rate of charge transport within monolayers in systems such as dye sensitized solar cells. We used quasi-elastic neutron scattering (QENS) to evaluate the possible dynamics of two small dye moieties, isonicotinic acid (INA) and bis-isonicotinic acid (BINA), attached to TiO₂ nanoparticles via carboxylate groups. The scattering data indicate that moieties are immobile and do not rotate around the anchoring groups on timescales between around 10 ps and a few ns (corresponding to the instrumental range). This gives an upper limit for the rate at which conformational fluctuations can assist charge transport between anchored molecules. Our observations suggest that if the conformation of larger dye molecules varies with time, it

SUBMITTER: Vaissier V 

PROVIDER: S-EPMC5171786 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature