Carbazole Based Ambipolar Compounds: A Study of Their Intramolecular Charge Transfer Properties
Date of Award
Doctor of Philosophy (Ph.D.)
Douglas Neckers, PhD
Massimo Olivucci, PhD (Committee Co-Chair)
Marshall Wilson, PhD (Committee Member)
Felix Castellano, PhD (Committee Member)
Lee Meserve, PhD
The present manuscript describes the synthesis and photophysical properties of six carbazole-based ambipolar compounds with donor-acceptor-donor (hereafter D-A-D) configuration in C2v symmetric arrangement. Three acceptor units were chosen based on their known optical properties, symmetry and planarity: fluorenone (FO), fluoren-9-ylidene malononitrile (FM), and dibenz[a,c]phenazine (Pz). Such units were connected through a phenylacetylene (PA) bridge (B) to favor structural rigidity and keep D-A distances fairly constant. The acceptor unit was functionalized through their common biphenylene skeleton via 3,3' and 4,4' substitutions (in the manuscript they adopt the numerology from fluorene). The triads B-A-B were also synthesized for comparison purposes. The photophysical properties have been investigated by means of steady state and time resolved UV-Vis absorption and photoluminescence, plus cyclic voltammetry. Computational methods such as density functional theory (DFT) and post self-consistent field (SCF) (i.e. complete active space SCF, or CASSCF) were utilized to map the electronic properties of the derivatives and perform a first survey of the possible non-radiative relaxation mechanism of their S1 state. The focus of these studies was based on the structure-activity relationship between the pattern of substitution and the electronic properties of the bulk. This helped establishing design patterns for the next generation of chromophores to be utilized in organic electronics applications such as thin-film transistors and photovoltaics, based on these D and A units.
Estrada, Leandro, "Carbazole Based Ambipolar Compounds: A Study of Their Intramolecular Charge Transfer Properties" (2010). Photochemical Sciences Ph.D. Dissertations. 38.