Conjugated chromophores optical properties

Fig. 8. Examples of some of the donor-acceptor substituted TEEs prepared for the exploration of structure-property relationships in the second- and third-order nonlinear optical effects of fully two-dimensionally-conjugated chromophores. For all compounds, the second hyperpolarizability y [10 esu], measured by third harmonic generation experiments in CHCI3 solution at a laser frequency of either A = 1.9 or 2.1 (second value if shown) pm is given in parentheses. n.o. not obtained...

The optical properties of AuNPs of different size and shape have been studied,121-123 as well as those of materials based on chromophore-gold nanoparticle conjugates.124... 

Many of the hyperbranched polymers contain aromatic chromophores in their 7r-conjugated structures and should show interesting optical properties [31]. This is indeed the case. For example, hb-P20 carries the TPA chro-mophore, which is often used as hole-transport materials in the fabrication of light-emitting diodes [120]. The Aab of triyne 20 appeared at 342 nm (Fig. 5),... 

Semi-empirical ZINDO SOS (sum over states) and ab initio quadratic response function (DDRPA) calculations on a series of D-A-substituted 7t-conjugated chromophores based on styryl benzothiazoles were used to aid in the design of dyes with high nonlinear optical properties <2004PCP495>. 

For copolymers of structure I, for both types of side-chains, there is a striking similarity with the optical properties of the corresponding models the absorption and photoluminescence maxima of the polymers are only 0.08-0.09 eV red-shifted relative to those of the models, as shown in Figure 16-9 (left) for the octyloxy-substituted compounds. The small shift can be readily explained by the fact that in the copolymers the chromophores are actually substituted by silylene units, which have a weakly electron-donating character. The shifts between absorption and luminescence maxima are exactly the same for polymers and models and the width of the emission bands is almost identical. The quantum yields are only slightly reduced in the polymers. These results confirm that the active chromophores are the PPV-type blocks and that the silylene unit is an efficient ti-conjugation interrupter. 

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