Theory-Guided Design and Synthesis of Multichromophore Dendrimers:  An Analysis of the Electro-optic Effect

Abstract

Extensive experimental and theoretical study suggests that interchromophore electrostatic interactions are among the most severe impediments to the induction and stability of large electro-optic coefficients in electric-field-poled organic materials. In this report, multichromophore-containing dendritic materials have been investigated as a means to minimize unwanted attenuation of nonlinear optical (electro-optic) activity at high chromophore loading. The dendritic molecular architectures employed were designed to provide optimized molecular scaffolding for electric-field-induced molecular reorientation. Design parameters were based upon past experimental results in conjunction with statistical and quantum mechanical modeling. The electro-optic behavior of these materials was evaluated through experimental and theoretical analysis. Experimental data collected from the dendrimer structures depict a reasonably linear relationship between chromophore number density (N) and electro-optic activity (r(33)) demonstrating a deviation from the dipolar frustration that typically limits r(33) in conventional chromophore/polymer composite materials. The observed linear dependence holds at higher chromophore densities than those that have been found to be practical in systems of organic NLO chromophores dispersed in polymer hosts. Theoretical analysis of these results using Monte Carlo modeling reproduces the experimentally observed trends confirming linear dependence of electro-optic activity on N in the dendrimer materials. These results provide new insight into the ordering behavior of EO dendrimers and demonstrate that the frequently observed asymptotic dependence of electro-optic activity on chromophore number density may be overcome through rational design.

High-Speed, Low Drive-Voltage Silicon-Organic Hybrid Modulator Based on a Binary-Chromophore Electro-Optic Material

“…The voltage-dependent transmission of the MZM is depicted in Fig. 3(b) and we extract U π = 1.22 V. Note that for this material, the achieved in device EO coefficien r 33 is even higher than its bulk-material counterpart: In bulk reference samples, EO coefficient of r 33 = 90 pm/V were measured at a poling fiel of E poling = 90V/μm [31]. Even though this corresponds to a much higher poling efficien y of r 33 /E poling =1.04 nm 2 /V 2 , the achievable EO coefficien is smaller due to the early onset of dielectric breakdown, which limits the maximum applicable poling fiel to ∼100 V/μm in bulk PSLD41.…”

“…2(b), consists of a central connecting motif to which three EO substructures are attached (marked in green). This results in a spherical shape of the molecule, which is known to lead to an improved poling efficien y as compared to oblate and prolate structures [29], [31]. In addition, perfluoraryl containing side-groups (marked in blue) are attached to the EO substructures.…”

“…In addition, perfluoraryl containing side-groups (marked in blue) are attached to the EO substructures. These site-isolation groups effectively reduce the dipole-dipole interaction of neighboring molecules [31]. This way, PSLD41 can be used as a neat material without the need of an isolating polymer matrix.…”

Nano-Engineering of Molecular Interactions in Organic Electro-Optic Materials

“…The specific theoretical methods of rigid body Monte Carlo (RBMC), fully atomistic Monte Carlo (FAMC) and molecular dynamics (MD) have been crucial (Sullivan et. al., 2009;Rommel & Robinson, 2007;Robinson& Dalton, 2000;Leahy-Hoppa et. al., 2006;Knorr et.…”

Ar–ArF Self‐Assembly of Star‐Shaped Second‐Order Nonlinear Optical Chromophores Achieving Large Macroscopic Nonlinearities

“…[5,[9][10][11] In the past two decades, a wide variety of dendritic NLO materials with very promising macroscopic NLO effects have www.advelectronicmat.de their low synthetic complexity but high NLO activities. [16,18,[28][29][30][31][32][33][34] Thus, to further explore the advantages of this structure, in this communication, three simple, multibranched NLO materials T1-T3 (Figure 1) were prepared using triphenylamine as the core to link pentafluorobenzene groups modified azobenzenebased chromophores. In T1-T3, the number of chromophore arms attached to the core was changed from one to three with an attempt in studying the effect of this adjusted molecular structure on the bulky structure and consequent macroscopic NLO effects.…”