TY - JOUR
T1 - Dual-Redox System of Metallo-Supramolecular Polymers for Visible-to-Near-IR Modulable Electrochromism and Durable Device Fabrication
AU - Mondal, Sanjoy
AU - Chandra Santra, Dines
AU - Ninomiya, Yoshikazu
AU - Yoshida, Takefumi
AU - Higuchi, Masayoshi
N1 - Funding Information:
This research work was financially supported by the CREST project (grant number: JPMJCR1533) from the Japan Science and Technology Agency (JST).
Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/12/30
Y1 - 2020/12/30
N2 - Dual-redox metallo-supramolecular polymers with a zigzag structure (polyFe-N and polyRu-N) were successfully synthesized by 1:1 complexation of a redox-active Fe(II) or Ru(II) ion and 4,4-bis(2,2:6,2-terpyridinyl)phenyl-triphenylamine (LTPA) as a redox-active ligand. The polymers had high solubility in methanol, and the polymer solutions showed dark brown (polyFe-N) or orange-red (polyRu-N) coloration. UV-vis spectra of the polymers displayed a strong metal-to-ligand charge transfer (MLCT) absorption in the visible region. Cyclic voltammograms of the polymer films exhibited two pairs of reversible redox waves. The first redox at ∼0.5 V versus Ag/Ag+ was assigned to the redox in the triphenylamine (TPA) moiety of LTPA, and the second redox at 0.8 V versus Ag/Ag+ (polyFe-N) or 0.9 V versus Ag/Ag+ (polyRu-N) was given to the redox of Fe(II)/(III) or Ru(II)/(III), respectively. Upon applying a positive potential of more than 0.5 V versus Ag/Ag+ to the polymer films, a new absorption at ∼820 nm in the near-infrared (NIR) region appeared with wide tailing to the longer wavelength. It is considered that the new absorption in the NIR region is caused by the polaron band of the oxidized ligand in the polymers. When the applied potential was increased to 1.0 V versus Ag/Ag+ (polyFe-N) or 1.1 V versus Ag/Ag+ (polyRu-N), the maximum wavelength of the new absorption in the NIR region shifted to 885-900 nm and the absorbance was further enhanced with disappearance of the MLCT absorption. Eventually, the original colors of the polymers were faint to light green. This visible-to-NIR electrochromism was reversible, and maximum optical contrast (ΔT) reached 52% in the visible region and 80% in the NIR region. A prototype solid-state device with the polymer was fabricated for practical utilization, exhibiting excellent cycle stability of >4000 cycles with maintaining high optical contrast from the visible-to-NIR range.
AB - Dual-redox metallo-supramolecular polymers with a zigzag structure (polyFe-N and polyRu-N) were successfully synthesized by 1:1 complexation of a redox-active Fe(II) or Ru(II) ion and 4,4-bis(2,2:6,2-terpyridinyl)phenyl-triphenylamine (LTPA) as a redox-active ligand. The polymers had high solubility in methanol, and the polymer solutions showed dark brown (polyFe-N) or orange-red (polyRu-N) coloration. UV-vis spectra of the polymers displayed a strong metal-to-ligand charge transfer (MLCT) absorption in the visible region. Cyclic voltammograms of the polymer films exhibited two pairs of reversible redox waves. The first redox at ∼0.5 V versus Ag/Ag+ was assigned to the redox in the triphenylamine (TPA) moiety of LTPA, and the second redox at 0.8 V versus Ag/Ag+ (polyFe-N) or 0.9 V versus Ag/Ag+ (polyRu-N) was given to the redox of Fe(II)/(III) or Ru(II)/(III), respectively. Upon applying a positive potential of more than 0.5 V versus Ag/Ag+ to the polymer films, a new absorption at ∼820 nm in the near-infrared (NIR) region appeared with wide tailing to the longer wavelength. It is considered that the new absorption in the NIR region is caused by the polaron band of the oxidized ligand in the polymers. When the applied potential was increased to 1.0 V versus Ag/Ag+ (polyFe-N) or 1.1 V versus Ag/Ag+ (polyRu-N), the maximum wavelength of the new absorption in the NIR region shifted to 885-900 nm and the absorbance was further enhanced with disappearance of the MLCT absorption. Eventually, the original colors of the polymers were faint to light green. This visible-to-NIR electrochromism was reversible, and maximum optical contrast (ΔT) reached 52% in the visible region and 80% in the NIR region. A prototype solid-state device with the polymer was fabricated for practical utilization, exhibiting excellent cycle stability of >4000 cycles with maintaining high optical contrast from the visible-to-NIR range.
KW - cycle stability
KW - device
KW - electrochromism
KW - metallo-supramolecular polymer
KW - near-IR
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U2 - 10.1021/acsami.0c18109
DO - 10.1021/acsami.0c18109
M3 - Article
C2 - 33326234
AN - SCOPUS:85098986890
VL - 12
SP - 58277
EP - 58286
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
SN - 1944-8244
IS - 52
ER -