Yutaka Ohsedo

Electrochromic properties of new methacrylate copolymers containing pendant oligothiophene and oligo(ethyleneoxide) moieties in the presence of a polymer-gel electrolyte

Abstract Electrochromic properties of new methacrylate copolymers containing pendant terthiophene and oligo(ethyleneoxide) moieties, poly[(2,2′:5′,2″-terthiophen-5-yl)methyl methacrylate- co -α-ethoxy-ω-methacryloyl-oligo(ethyleneoxide)] (poly(MA3T- co -MAEO)), in the presence of a polymer–gel electrolyte were studied. A polymer–gel electrolyte composed of poly(methylmethacrylate), lithium perchlorate, and propylene carbonate was sandwiched between two indiumtin oxide (ITO)-coated glass substrates, on one of which a film of poly(MA3T- co -MAEO) was coated. The device was found to undergo a color change from yellowish–orange to pale green and vice versa on electrochemical oxidation and reduction. The response times for green coloration and decoloration of a poly(MA3Tco-MAEO) 60/40 film in the presence of the polymer–gel electrolyte were estimated to be 5.3 and 5.5 s, respectively.

Synthesis and electrochromic properties of a methacrylate polymer containing pendant terthiophene

Abstract A new methacrylate polymer containing terthiophene as a pendant group, poly[(2,2′:5′,2″-terthiophen-5-y) methyl methacrylate], has been prepared by radical polymerization of the corresponding monomer and its electrochromic properties have been examined. Electrochemical oxidation of the polymer in the presence of tetra-n-butylammonium perchlorate produced a purple-colored electrochemically doped polymer, which was identified as a radical-cation salt of pendant terthiophene with ClO 4 − as a dopant. The polymer undergoes a reversible clear color change from pale yellow to purple and vice versa on electrochemical doping and dedoping and is expected to be a potential electrochromic material.

Hole-transporting and emitting pendant polymers for organic electroluminescent devices

New hole-transporting pendant polymers with high glass-transition temperatures (Tgs) above 200 °C were designed and synthesized. Multilayer organic electroluminescent (EL) devices using the new polymers as the hole-transport layer and quinacridone-doped tris(8-quinolinolato)aluminum as the emitting layer exhibited high performance. One of the hole-transporting polymers functioned well as a hole injection buffer layer in organic EL devices. New green- and orange-emitting pendant polymers with high Tgs and desired ambipolar character were also designed and synthesized. Organic EL devices using these emitting polymers also exhibited good performance. One of the hole-transporting polymer showed a high hole carrier mobility of over 10-3 cm2V-1s-1 at an electric field of 1.0 × 105 Vcm-1, as determined by a time-of-flight method.