Molecular Design and Supramolecular Organization of Highly Efficient Nonlinear Optical Chromophores for Exceptional Electro-Optic Properties

Abstract

Arene-perfluoroarene stacking interactions are explored in a new series of dendronized nonlinear optical (NLO) chromophores to create extended network structures and overcome intermolecular electrostatic interactions for improving their poling efficiency and alignment stability. These supramolecular self-assembled molecular glasses showed ultrahigh electro-optic (EO) activity (r 33 > 300 pm/V) and excellent thermal stability (at 85°C). These unprecedented EO activities could inspire the vigorous development of new integrated optical devices.Organic and polymeric electro-optic (EO) materials have been intensively studied for several decades due to their potential applications for the high speed/broad bandwidth information technologies (1-3), terahertz radiation generation and detection (4, 5), integrated circuitry, and multifunctional microand nanodevices (6-8). Their development is motivated not only by the large nonlinear optical (NLO) susceptibilities, but also by the versatility, ease of processability, and possibility of tailoring the physicochemical properties through In Organic Thin Films for Photonic Applications; Herman, W., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2010.molecular engineering. Recently, significant advances (9, 10) in the design and synthesis of new-generation organic EO materials have led to the successful demonstration of ultralarge EO coefficients (r 33 values) of greater than 300 pm/V. This breakthrough result allowed organic NLO materials to significantly surpass the EO properties of lithium niobate, the dominant inorganic material currently used in modern EO modulator technology. These materials with such high EO activities and unprecedented performance in conventional device formats provide a powerful platform for building innovative devices such as hybrid systems using EO polymers integrated with silicon photonics (11,12).

Systematic Nanoengineering of Soft Matter Organic Electro-optic Materials

“…This research has been covered in other reviews (and references cited therein including to even earlier reviews). [4][5][6][7][8][9][10][11][12][13][14] Another factor which has recently impacted the commercial viability of ONLO materials is the advance in device engineering, particularly the advent of silicon photonics. [10][11][12][15][16][17][18][19][20] The high index of refraction of silicon has permitted a dramatic reduction in the size of photonic circuitry.…”

Extended First Hyperpolarizability of Quasi-Octupolar Molecules by Halogenated Methylation: Whether the Iodine Atom is the Best Choice

“…The remarkable positive contribution principally stems from the top DPA moiety, and most of the negative contribution is located near the central ring for each species. Clearly, the value of −zρ zz (2) ⃗ r ( ) function becomes increasingly sparse with the increase of atomic number of halogens in the dye from F to I. This is particularly evident for the negative spatial distributions in the closest branch to halogen (the left branch) of molecules.…”

“…Simultaneously, for ease of operation and discussion, the direction of dipole moments was adjusted to coincide with the z-axis, and the halogen atoms were set at the original points of the coordinate system. Thereby, the hyperpolarizability density we are concerned about corresponds to ρ zz (2) ⃗ r ( ). The visualized results of the −zρ zz…”

“…For a long time, the nonlinearity of the molecule has been one of the most important properties that people have been paying close attention to. The preparation of effective nonlinear optical (NLO) materials has always been a hot topic in the field of photoelectric functional material design. − So far, many kinds of NLO chromophores, such as organic dyes, inorganic molecules, or metal clusters, have emerged endlessly. − For purely organic dyes, it is a well-established rule that a molecule with a strong electron donor (D) connected to a powerful electron acceptor (A) through a π-bridging system, known as the D−π–A-type dipolar compound, usually exhibits large molecular first hyperpolarizability and then affects second-order (quadratic) NLO susceptibilities of the bulk material containing it. ,− Based on this conception, a large number of extended conjugated systems, such as quadrupolar (D−π–A−π–D, A−π–D−π–A,...) − and octupolar ((D−π) 3 –A, (A−π) 3 –D,...) − organic molecules, was designed in theory and/or synthesized in experiment.…”

Linear and Nonlinear Optical Properties of Triphenylamine–Indandione Chromophores: Theoretical Study of the Structure–Function Relationship under the Combined Action of Substituent and Symmetry Change

“…In the past 20 years, the design and synthesis of organic nonlinear optical (NLO) materials have received a great deal of interest, both experimentally and theoretically. − Scientists have continuously proposed different strategies for achieving high-performance photoelectric functional molecules. − ,− For purely organic compounds, a well-established method used to increase molecular NLO responses is the modification of the molecules with some electron donor (D) and/or acceptor (A) groups. − The introduction of electron donor and/or acceptor unit(s) can increase the polarization abilities and reduce the optical gap of NLO chromophores. Besides, the fact that the consequent symmetry breaking of the molecules is also one of the critical factors in changing their optical properties is often neglected.…”