title: Photoluminescence Efficiency of Substituted Quaterthiophene Crystals.
abstract: The photoluminescence (PL) efficiency of substituted alpha-conjugated quaterthiophene crystals shows marked differences depending on crystal packing and molecular geometry. This effect is studied by evaluating the role of the intermolecular interactions and the effects of the single molecule conformation on the intersystem crossing (ISC) rate. The comparison of these calculations with absolute quantum efficiency measurements and with the experimental temperature dependence of the PL decay time, indicates that the differences in PL efficiency are not inherent to crystal packing effects but they are determined by the ISC rate.
authors.affiliation: Istituto Nazionale di Fisica della Materia, Dipartimento di Ingegneria dell'Innovazione, Università di Lecce, Via Arnesano, 73100 Lecce, Italy.
authors.initials: G
authors.lastname: Gigli
authors.lastname: Della Sala F
authors.initials: M
authors.lastname: Lomascolo
authors.initials: M
authors.lastname: Anni
authors.initials: G
authors.lastname: Barbarella
authors.lastname: Di Carlo A
authors.initials: P
authors.lastname: Lugli
authors.initials: R
authors.lastname: Cingolani