Abstract
We introduce the first π-conjugated polymer-based, black-to-transmissive and multicolored switching electrochromic device (ECD) constructed in a Pseudo 3-ElectrodeElectrochromicDevice (P3-ECD) architecture. In this ECD, the non-electrochromic, yet electroactive, polymer poly(3,4-propylenedioxypyrrole-N- propionitrile) (PProDOP-N-EtCN) serves as a counter electrode material.This transmissive polymer helps eliminate the contrast limitations seen in dual polymer ECDs that use combinations of anodically and cathodically coloring polymers. The P3-ECD adds colors by transmitting light through two independently controlled working electrodes (coated with two different electrochromic polymer films) and two counter electrodes (coated with PProDOP-N-EtCN) stacked together with a gel electrolyte. The two cathodically coloring EC polymers that were used in this work are, a diestersubstituted poly(3,4-propylenedioxythiophene) (PProDOT-(CH2CO2C12H25) 2) for the first one, namely PProDOT-ester, and a donor-acceptor analogue, namely PProDOT-BTD, which consists of a specific alternation of donor and acceptor building units spanning the electron-rich 3,4-thylenedioxythiophene (EDOT), 2-ethylhexyloxy-substituted 3,4-propylenedioxythiophene ProDOT-(CH 2O(2-EtHx))2 and the electron-deficient 2,1,3-benzothiadiazole (BTD). The PProDOT-ester switches from a deep purple (L* = 41 a* = 22 b* = -48) to a highly transmissive gray/blue (L* = 87 a*=-2 b*=-7),while the PProDOT-BTD switches from a deep green (L*=60, a*=-23, b*= 12) to transmissive sky blue (L*=84, a*=-4, b*=-6). Utilizing PProDOT-ester and PProDOTBTDin their neutral form in the P3-ECD yields a deep blue-black with color coordinates of L*=26 ,a* =-3, b*=-17 switching to a transmissive statewith color coordinates of L*=75, a*=-7, b*=-7. The device has a highMichelson contrast of 0.8 (which can range from0 to 1). Separate potential control over the electrodes allows colormixing of the polymers in intermediate oxidation states in the P3-ECD. As such, a full palette of colors is accessible through proper choice of EC materials as desired for the construction of multicolored information displays, and in the case of black-to-transmissive electronic paper.
Original language | English (US) |
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Pages (from-to) | 5145-5153 |
Number of pages | 9 |
Journal | Chemistry of Materials |
Volume | 21 |
Issue number | 21 |
DOIs | |
State | Published - Nov 10 2009 |
Externally published | Yes |
ASJC Scopus subject areas
- General Chemistry
- General Chemical Engineering
- Materials Chemistry