Hole-vibronic coupling in oligothiophenes: impact of backbone torsional flexibility on relaxation energies.
Density functional theory calculations together with highly resolved gas-phase ultraviolet photoelectron spectroscopy have been applied to oligothiophene chains with up to eight thiophene rings. One of the important parameters governing the charge transport properties in the condensed phase is the amount of energy relaxation upon ionization. Here, we investigate the impact on this parameter of the backbone flexibility present in oligothiophenes as a result of inter-ring torsional motions. With respect to oligoacenes that are characterized by a coplanar and rigid backbone, the torsional flexibility in oligothiophenes adds to the relaxation energy and leads to the broadening of the first ionization peak, making its analysis more complex.
Filho
Demetrio A da Silva
DA
School of Chemistry and Biochemistry, Centre for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA.
Coropceanu
Veaceslav
V
Fichou
Denis
D
Gruhn
Nadine E
NE
Bill
Tonja G
TG
Gierschner
Johannes
J
Cornil
Jérôme
J
Brédas
Jean-Luc
JL