All-polymeric electrochromic and photoelectrochemical devices: new advances

Flexible and solid-state electrochromic and photoelectrochemical devices were assembled using PET-ITO flexible electrodes as substrate to the electroactive layers and a polymer electrolyte based on poly(epichlorohydrin-co-ethylene oxide). Large area all-polymeric electrochromic device (20 cm(2)) consisted of a sandwich-type cell of electrodes modified with poly(o-methoxy aniline) and poly(3,4-ethylene dioxythiophene)-poly(styrene sulfonate) films. The device exhibited a very high optical contrast (transparent to dark blue), with DeltaT% = 75% at lambda = 640 nm, however, it partially loses optical contrast after 100 redox cycles, resulting in DeltaT% = 42%. The solid-state flexible photoelectrochemical solar cell consisted of a dye-sensitized porous TiO2 electrode and a Pt counter-electrode assembled with the polymer electrolyte containing the I-3(-)/I- redox couple. This cell exhibited an open circuit potential of 0.83 V, a short-circuit photocurrent of 0.19 mA cm(-2) and an efficiency of 0.09% (100 mWcm(-2)). The low efficiency for energy conversion, in comparison to cells with liquid electrolytes, was attributed to the polymer electrolyte and the reduced mobility of I-3(-) in such medium as well as to the poor electronic contact between the TiO2 particles in the porous film, (C) 2001 Elsevier Science Ltd. All rights reserved.