A new organo-inorganic hybrid of poly(cyclotriphosphazene-4,4′-bipyridinium)chloride with a large electrochromic contrast

Abstract

A new organo-inorganic hybrid electrochromic material poly(cyclotriphosphazene-4,4 0 -bipyridinium)chloride salt was synthesized wherein each phosphorus atom in the triphosphazene core is linked by diquaternized 4,4 0 -bipyridyls (PPBP). The electrochrome was characterized by 31 P nuclear magnetic resonance, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). XPS confirmed the formation of P-N + and P-N linkages in the PPBP and the conversion of covalently bound Cl to ionic Cl À species. The transparent PPBP material undergoes three reversible one electron-transfer reactions to yield a radical cation insoluble film which first acquires a purple hue and then turns deep blue. Electrochromic devices were constructed with the PPBP hybrid dissolved in a highly conductive, thermally stable and electrochemically inert ionic liquid based gel electrolyte and a Prussian blue (PB) layer as the anode. The PPBP-PB device showed an extremely large coloration efficiency of 504 cm 2 C À1 , an exceptionally high transmission modulation of 70.5% at 590 nm, one among the highest reported contrasts in organic electrochromics, a large reflectance contrast of 59.2% at 545 nm and fast switching kinetics. The device was durable as it retained 96.2% of its original transmission after 1000 color-bleach cycles, thus exemplifying its use for both reflective and transmissive electrochromic applications.Electrochemical impedance studies revealed charge transfer to be a less resistive process during reduction relative to oxidation which cumulatively ensues in shorter coloration times. Our studies demonstrate the yet untapped potential of the inorganic (PNCl 2 ) 3 in steering the synthesis of new organo-inorganic hybrid materials, capable of undergoing facile redox phenomena, manifesting in unequalled functional properties and thereby offering opportunities to use this trimer for preparing a whole gamut of new high performance electroactive compounds.

A high contrast solid-state electrochromic device based on nano-structural Prussian blue and poly(butyl viologen) thin films

“…The maximum reflectance change of the device from 1000 to 2500 nm is about 14%. The decrements of the transmittance and reflectance of the ECD were caused by the higher absorbance in the darkened state [39][40][41], which is consistent with Fig. 6.…”

Thin cyclomatrix polyphosphazene films: interfacial polymerization of hexachlorocyclotriphosphazene with aromatic biphenols

“…The broad band from 1200-1120 cm −1 , with a peak at 1150 cm −1 , originates from the asymmetric PvN−P stretching, while the peak at 870-880 cm −1 belongs to the symmetric PvN−P stretching. 25,26,42 The absorbance peak at 940 cm −1 originates from the P−O−Ph bond, indicating the successful preparation of a cross-linked network for all aromatic monomers used.…”

Integrating boron atoms into ultrathin organic polymer for visible light photocatalytic CO2reduction to CH4with nearly 100% selectivity

“…[43][44][45] Obviously, a different peak at 288.5 eV appears in the C 1s peak of the CP sample, which is attributed to the C-O bond. 46 As the number of aromatic rings in the monomer declines, the area of C-H also decreases signicantly. In the O 1s spectra of the 2CPB sample (Fig.…”