Asymmetric mono cationic 4,4′-bipyridiniums, 1 -butyl-4,4′- bipyridinium bromide (BUBP) and 1-methyl-4,4′-bipyridinium iodide (MEBP) showed electrochromic properties from blue to transparent yellow. The electrochromic bipyridiniums, BUBP and MEBP, were introduced to solid state electrochromic cells by using a solution of the bipyridinium, TiO 2, and polymer electrolyte composite. The 4,4′-bipyridinium derivatives was attached to TiO 2 nanoparticles and decreased aggregation of TiO 2 to afford EC dye-TiO 2 nanoparticles with average diameter smaller than 20 nm, as determined by FE-SEM. An all solid state electrochromic cells prepared from the dye-TiO 2 nanoparticles showed improved electrochromic response compared to that without TiO 2. Thus the cell from the BUBP- TiO 2 nanoparticles responded to a step potential of ±2 V within 7 sec with coloration efficiency of 117. The redox cyclability of the bipyridinium-TiO 2 nanoparticles cell was longer than that of the TiO 2 free cells. The enhanced properties were attributed to the conductivity and the large surface area of TiO 2 nanoparticles.
All Science Journal Classification (ASJC) codes
- General Chemistry
- Biomedical Engineering
- General Materials Science
- Condensed Matter Physics