Color engineering of π-conjugated donor-acceptor systems : the role of donor and acceptor units on the neutral state color

Design of a monomer is a viable route for adjusting the properties of its corresponding polymer. The main goal of this study is to design and synthesize novel soluble polymers having various colors of color palette and amenable for use in electrochromic device applications. In designing the monomers, the factors affecting the properties of the polymers are also considered. For this purpose, each part of the monomers is chosen properly for each desirable properties and the effect of them is investigated separetely. Thus, this study is based on the investigation of the effect of three major parts on the polymer properties: Donor groups, acceptor groups and the length of alkyl chain. For this aim, nine D-A-D type monomers, TSeT, ESeE, PSeP-C10, PSP-C10, PNP-C10, POP-C10, PSeP-C4, PSP-C4 and PSP-C6, and their corresponding polymers, P(TSeT), P(ESeE), P(PSeP-C10), P(PSP-C10), P(PNP-C10), P(POP-C10), P(PSeP-C4), P(PSP-C4) and P(PSP-C6), based on thiophene, 3,4-ethylenedioxythiophene (EDOT), and 3,3-dialkyl-3,4-dihydro-2H-thieno[3,4-b]-[1,4]dioxepine (ProDOT-Cn) as D units and 2,1,3-benzoselenadiazole, 2,1,3-benzothiadiazole, 2-decyl-2H-benzo[d][1,2,3]triazole, and 2,1,3-benzooxadiazole as A units were synthesized. The obtained polymers have somewhat low band gap between 1.13 eV and 1.80 eV, they show electrochromic behaviors. Among them P(POP-C10), P(PSP-C10) and P(PSP-C6) have cyan color which is one leg of CMY (Cyan-Magenta-Yellow) color spaces. Since there have been scant studies on cyan colored polymers in the literature, these polymers are so precious. Via copolymerization of PNP-C10 and PSeP-C10, the first electrochemically synthesized neutral state black polymer was obtained.Ph.D. - Doctoral Progra

Furan and benzochalcogenodiazole based multichromic polymers via a donor-acceptor approach

Two new furan and benzochalcogenodiazole based monomers, namely 4,7-di(furan-2-yl) benzo[c][1,2,5]-selenadiazole (FSeF) and 4,7-di(furan-2-yl) benzo[c][1,2,5]thiadiazole (FSF), were designed and synthesized via a donor-acceptor-donor approach. The monomers were electrochemically polymerized via potentiodynamic or potentiostatic methods. The monomers and their polymers exhibited lower oxidation potentials (1.16 V and 1.06 V for monomers; 0.93 V and 0.80 V for polymers vs. Ag/AgCl) and red shifts of the whole dual-band absorption spectra upon moving from S to Se. Intramolecular charge transfer properties of the monomers and the polymers were demonstrated by using electroanalytical and optical methods. Also, the polymers PFSeF and PFSF were multicolored at different redox states and have low band gaps of 1.43 eV and 1.61 eV, respectively

A platform to synthesize a soluble poly(3,4-ethylenedioxythiophene) analogue

Alkyl-substituted polyhedral oligomeric silsesquioxane (POSS) cage is combined with 3,4-ethylenedioxythiophene under the same roof. The corresponding monomer called EDOT-POSS is used to get soluble poly(3,4-ethylenedioxythiophene) (PEDOT-POSS) analogue. Both chemically and electrochemically obtained polymers are soluble in common organic solvents like dichloromethane, chloroform, tetrahydrofuran, and so forth. The PEDOT-POSS has somewhat higher band gap (1.71 eV at 618 nm) than its parent PEDOT (1.60 eV at 627 nm) and as expected the PEDOT-POSS exhibits higher optical contrast (74% at 618 nm) and coloration efficiency (582 cm(2)/C for 100% switching), lower switching time (0.9 s), higher electrochemical stability (93% of its electroactivity retains after 5000 cycles under ambient conditions) when compared to the PEDOT. A number of advantages of the PEDOT-POSS over the PEDOT can make it a promising material in the areas of electro-optical applications. (C) 2017 Wiley Periodicals, Inc