Structure-Photoluminescence Correlation for Two Crystalline Polymorphs of a Thiophene-Phenylene Co-Oligomer with Bulky Terminal Substituents.
Two crystal polymorphs of a thiophene-phenylene hexamer with bulky terminal substituents are characterized by different molecular conformations and parallel versus herringbone packing. Irrespective of their similar emissive spectra and common H-aggregate features, evidenced by crystal structure analysis and confirmed by solid-phase and excited-state first-principles calculations, their luminescence is relatively high and, for one form, nearly double than that for the other. Interaromatic packing energy contributions are established by quantum chemical calculations and can be compared quantitatively as the same species in different crystal environments is examined. The different luminescence efficiency of the two phases highlights the crucial role of the interaromatic packing for the luminescence properties of polyaromatic oligomers.
†Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, P.zza L. Da Vinci 32, 20133 Milano, Italy.
Tommaso
T
Nicolini
†Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, P.zza L. Da Vinci 32, 20133 Milano, Italy.
Antonino
A
Famulari
†Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, P.zza L. Da Vinci 32, 20133 Milano, Italy.|‡Center for Nano Science and Technology@Polimi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy.
Teresa
T
Gatti
‡Center for Nano Science and Technology@Polimi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy.
Javier
J
Martí-Rujas
§Istituto per lo Studio delle Macromolecole (ISMAC), CNR, Via Bassini 15, 20133 Milano, Italy.
Francesca
F
Villafiorita-Monteleone
‡Center for Nano Science and Technology@Polimi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy.
Eleonora V
EV
Canesi
⊥Dipartimento Scienze dei Materiali, Università degli Studi di Milano Bicocca, Via Cozzi 55, 20125 Milano, Italy.
Francesco
F
Meinardi
§Istituto per lo Studio delle Macromolecole (ISMAC), CNR, Via Bassini 15, 20133 Milano, Italy.
Chiara
C
Botta
‡Center for Nano Science and Technology@Polimi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy.
Emilio
E
Parisini
†Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, P.zza L. Da Vinci 32, 20133 Milano, Italy.
Stefano Valdo
SV
Meille
†Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, P.zza L. Da Vinci 32, 20133 Milano, Italy.|‡Center for Nano Science and Technology@Polimi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy.
Chiara
C
Bertarelli
CH−π interaction; TD-DFT excited states; conjugated OLED material; parallel versus herringbone stack; photoluminescence QY; thiophene−phenylene co-oligomer