화학공학소재연구정보센터
Electrochimica Acta, Vol.60, 339-346, 2012
Electrochromic films with high optical contrast prepared by oxidative electropolymerization of a novel multi-functionalized cyclometalating ligand and its neutral-charged Pt(II) complexes
A novel multi-functionalized cyclometalating ligand (HL) and its two neutral-charged Pt(II) complexes, i.e., [(L)PtCl] (C1) and [(L)Pt(C equivalent to CC6H5)] (C2) (HL=4-{p-[N-(4-(9-carbazole))butyl-N-phenyl]anilino}-6-phenyl-2,2'-bipyridine), have been successfully synthesized and verified by H-1 NMR, C-13 NMR, elemental analysis and/or X-ray crystallography. The introduction of the electron-donating arylamino unit at the 4-position of the electron-withdrawing 6-phenyl-2,2'-bipyridine ligand forms the D-A system, resulting in the enhanced (MLCT)-M-1 bands in the absorption spectra and intense orange emissions in the PL spectra of C1 and C2. The carbazole units grafted through alkyl chain in HL, C1 and C2 electrochemically trigger the efficient cross-linking reaction to form polymer films, which have been characterized by AC impedance, SEM and spectroelectrochemistry. Each of the poly-HL and poly-C1 films exhibits reversible oxidation with significant color change having a high contrast ratio (81.8% for poly-HL film and 67.3% for poly-C1 film), a reasonable coloration response time (6.3 s for poly-HL film and 3.1 s for poly-C1 film) and a comparable coloration efficiency (158C(-1) cm(2) for poly-HL film and 132C(-1) cm(2) for poly-C1 film) that can be switched by modulation of the applied potential. (C) 2011 Elsevier Ltd. All rights reserved.