The second-order nonlinear optical (NLO) properties of two tetrathiafulvalene (TTF)-fused electron donor-acceptor dyads have been determined using the Electric Field Induced Second Harmonic generation (EFISH) technique and theoretically rationalized. Dyads TTF-dppz (1) and TTF-BTD (2) were obtained by direct fusion of a TTF electron donor unit either with a dipyrido[3,2-a:2′,3′-c]phenazine (dppz) or a benzothiadiazole (BTD) electron acceptor moiety. Dyad 1 acts as a reversible acido-triggered NLO switch by protonation/deprotonation at two nitrogen atoms of the dppz acceptor moiety induced by sequential exposure to HCl and ammonia vapors. Dyad 2, on the other hand, displays redox-tunable NLO properties upon two consecutive oxidations to its radical cation 2+and dication 22+species. The resulting final dication 22+exhibits an inversion of the sign of β0, due to a completely inverted distribution of the frontier molecular orbitals with respect to those of its neutral species, leading to a scarcely polar species in the excited state, as indicated by the theoretical calculations.
|Titolo:||Stimuli-responsive NLO properties of tetrathiafulvalene-fused donor-acceptor chromophores|
|Parole Chiave:||Nonlinear-optical properties; intramolecular charge-transfer; ambipolar transport-properties; density-functional theory; field-effect transistors; sensitized solar-cells; push-pull; benzothiadiazole dyad; organic-compounds; TTF derivates|
|Settore Scientifico Disciplinare:||Settore CHIM/03 - Chimica Generale e Inorganica|
|Data di pubblicazione:||2017|
|Digital Object Identifier (DOI):||10.1039/c7cp04687a|
|Appare nelle tipologie:||01 - Articolo su periodico|