Organic Semiconductors at the University of Washington: Advancements in Materials Design and Synthesis and toward Industrial Scale Production

Abstract

Second-order NLO effects can be separated into two broad categories. The first category involves how light waves interact with an NLO medium, and it includes second-harmonic generation, sum-frequency generation, difference-frequency generation, and optical rectification. In the second category, called the electro-optic effect, an applied external electric field induces a linear change in refractive index of the NLO material. [10] Applications of the EO effect include phase modulators, Mach-Zehnder interferometers (Figure 1), in-phase-quadrature modulators, resonant antennae modulators, and ring resonators (wavelength division multiplexers), which are incredibly important commercially for transducing electrical to optical signals at high frequencies (GHz) for telecommunications over photonics fiber/wireless networks. The dominant EO material used commercially is lithium niobate, which is an inorganic crystal; however, organic materials have an inherent advantage for high-frequency applications as the polarization response in an organic molecule is dependent on the motions of electrons, which yield response times much faster (10 −14 s) than the polarization response times of inorganic EO materials (10 −10 s) which depend on the motions of ions. [10] Over the past ≈20 years, UW researchers (in the groups of Profs.

Sustainable Access to π-Conjugated Molecular Materials via Direct (Hetero)Arylation Reactions in Water and under Air

“…Comparatively fewer contributions are dedicated to the transition from proof of concept laboratory synthesis and characterization to the industrial environment. Aside from improved stability and processability, one of the main issues still hampering full industrial exploitation is the overall sustainability of the synthetic protocols [7][8][9]. Researchers working in the field of printed (opto)electronics are becoming increasingly aware of the need for materials combining reasonable performances with sustainable synthetic access [10,11].…”

Advances in applying C–H functionalization and naturally sourced building blocks in organic semiconductor synthesis

“…Direct arylation and oxidative C-H/C-H coupling are the two C-H activation involved synthetic routes for OSMs as green alternatives to the conventional synthetic methods, such as Suzuki and Stille couplings, due to their high atom economy (Scheme 2). [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] For instance, the atom economy of a Suzuki coupling shown in Scheme 1a is calculated to be 60%. If direct arylation and oxidative C-H/C-H coupling were used instead to synthesize the same organic semiconducting product in Scheme 1a, respectively, then the values of atom economy would be 80% for direct arylation and 99% for oxidative C-H/C-H coupling.…”

“…DArP, as an emerging subject in the field of OSM synthesis, has been reviewed many times in the past few years. [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] The semiconducting polymers synthesized via DArP are mostly linear homopolymers and alternating copolymers. When homopolymers are prepared using DArP, the monomer has a C-X (X = Cl, Br, I) bond and a C-H bond to proceed a head-to-tail polycondensation (Scheme 4, top).…”

“…Many scientific endeavors have been made to improve the environmental impact of OSMs, including shortening the synthetic routes by adopting C-H functionalization, applying green solvents, replacing the toxic and scarce metal catalysts with earth abundant (first row) transition metal catalysts, reducing the energy consumption by performing the synthesis under ambient conditions, as well as utilizing naturally sourced building blocks. [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] This review highlights the progress on enhancing the environmental friendliness of synthetic protocols, consisting of synthetic routes, reagents, reaction conditions, and building blocks of OSMs, made in the past four years to facilitate the large-scale production and commercialization of OSMs. Specifically, the purification and processing of OSMs are outside the scope of this review.…”

Temperature-dependent morphology-electron mobility correlations of naphthalene diimide-indacenodithiophene copolymers prepared via direct arylation polymerization

“…4,6 Especially donoracceptor copolymers have emerged as modular systems due to versatile tailoring of their structural and electronic properties by suitable selection of donor and acceptor blocks. [7][8][9] In the last decade, one focus has been the development of new n-type polymers for OSCs and OFETs. [10][11][12][13][14] Many of these n-type conjugated polymers are based on naphthalene diimide (NDI), perylene diimide (PDI) or bithiophene imide (BTI).…”