Flexible electrochromic windows: a comparison using liquid and solid electrolytes

Abstract

Neste trabalho foram montados e caracterizados dois dispositivos eletrocrômicos (ou janelas eletrocrômicas) utilizando como materiais opticamente ativos polímeros instrinsecamente condutores. Os materiais usados na montagem foram os mesmos, exceto pelo eletrólito usado. No primeiro foi usado como eletrólito uma solução de carbonato de propileno e no segundo o elastômero poli(epicloridrina-co-oxido de etileno), ambos contendo LiClO4. A condutividade elétrica do eletrólito líquido é aproximadamente duas ordens de grandeza maior (10 -3 S cm -1) do que a do eletrólito sólido e foram obtidos excelentes resultados do ponto de vista eletrocrômico em ambos os casos. A eficiência eletrocrômica em 640 nm foi calculada em 700 C cm -2 para o dispositivo com eletrólito liquido e 360 C cm -2 para o dispositivo montado com eletrólito sólido. O uso de dispositivos eletrocrômicos de estado sólido tem chamado bastante atenção e suas vantagens são discutidas.In the present work, two electrochromic devices (or electrochromic windows) based on intrinsically conducting polymers were assembled and characterized. For both devices, the materials used on the assembling were the same except for the electrolyte layer. In the first, we used as electrolyte a propylene carbonate solution and in the second the elastomer poly(epichlorohydrin-co-ethylene oxide), both containing LiClO4. The conductivity of the liquid electrolyte (10 -3 S cm -1) is approximately two orders of magnitude higher than for the solid electrolyte and we obtained very good electrochromic properties in both cases. The calculated electrochromic efficiency at 640 nm was 700 C cm -2 for the liquid electrolyte device and 360 C cm -2 for the solid state device. Solid state electrochromic windows have been investigated and some of its advantages over windows with liquid electrolytes are discussed.

Dual type complementary colored polymer electrochromic devices utilized by 3-ester substituted thiophenes

“…The color persistence in the ECDs is an important feature since it is directly related to aspects involved in its utilization and energy consumption during use [14]. changes to 80%.…”

Electrochromic Window Based on Conducting Poly(3,4-ethylenedioxythiophene)-Poly(styrene sulfonate)

“…[29] Carlberg [30] has reported important characterizations on this material, such as its high stability upon repeated electrochemical switching and fast kinetics, and she predicted the exceptional properties of poly(3,4-ethylenedioxythiophene) as a material for smart window applications. De Paoli and co-workers [31,32] investigated many polymeric solid state electrochromic devices and flexible electrochromic windows with the use of poly(3,4-ethylenedioxythiophene)±poly(styrene sulfonate) (PEDT/PSS). Reynolds' group synthesized new conducting poly(3,4-alkylenedioxythiophene) derivatives [33] and alkyl substituted poly (3,4-ethylenedioxythiophenes) [34,35] as fast electrochromics with high contrast ratios.…”

Solid-state electrochromic device based on two poly(thiophene) derivatives

“…65%, chromatic contrast at 485 and 725 nm between 30% and 40%, response time between 4 and 2 s, and good optical memory in its reduced state (E ¼ 0:0 V) under open circuit [19]. PEDT-PSS has been investigated previously by other authors, and its electrochromic behavior was confirmed [22,[28][29][30][31].…”

“…6 s). Other devices described in the literature and assembled using conducting polymers presented response time varying between 5 and 10 s [12,15,17,30,31]. This behavior suggests a faster response time for the reduction of poly(12-MFDDT)/ oxidation of PEDT-PSS than for the reverse process due to the faster kinetics of dopant ion diffusion.…”