Enhanced Contrast Dual Polymer Electrochromic Devices

Abstract

The ability to match two complementary polymers constitutes an important step forward in the design of electrochromic devices (ECDs). Here we show that the necessary control over the color, brightness, and environmental stability of an electrochromic window can be achieved through the careful design of anodically coloring polymers. For this purpose, we have constructed ECDs based on dimethyl substituted poly(3,4-propylenedioxythiophene) (PProDOT-Me 2 ) as a cathodically coloring layer, along with poly[3,6-bis(2-ethylenedioxythienyl)-N-methyl-carbazole] (PBEDOT-NMeCz) and N-propane sulfonated poly(3,4-propylenedioxypyrrole) (PProDOP-NPrS) as anodically coloring polymers. Comparison of the results shows that using PProDOP-NPrS as the high band gap polymer has several advantages over the carbazole counterpart. The main benefit is the opening of the transmissivity window throughout the entire visible spectrum by moving the π-π* transition of the neutral anodically coloring material into the ultraviolet region. Another advantage of the PProDOPNPrS based device is the noticeable increase in the optical contrast as evidenced by an increase in the transmittance change of the device (∆%T) from 56% to 68%, as measured at 580 nm. These devices exhibit a 60% change in luminance along with half-second switching times for full color change. Moreover, they were found to retain up to 86% of their optical response after 20 000 double potential steps, opening up new directions in optical technology.

RAFT “grafting-through” approach to surface-anchored polymers: Electrodeposition of an electroactive methacrylate monomer

“…In our group, carbazolecontaining polymers and dendrimers have been synthesized and studied [24][25][26][27][28] because of their potential applications on electroluminescent devices [29][30][31], photorefractive materials [32,33], electrochromic materials [34,35], and memory devices [36]. In all the above applications, the main use of carbazole-derivatized polymers for electro-optical function involves efficient hole transport, good solution processing properties, and high chemical stability [37][38][39][40].…”

Carbazole based electrochromic polymers with benzoazole units: Effect of heteroatom variation on electrochromic performance

“…Besides, these polymers demonstrate remarkable electrochromic properties due to the conjugation broken on the carbazyl nitrogen. One of the exciting multicolor polymer frameworks based on the 3,6-linked carbazole moiety was proposed by Reynolds and coworkers [18][19][20]. These polymers can form radical cations that are separated from each other owing to the broken conjugation on the polymer backbone.…”

Copolymerisation as a way to enhance the electrochromic properties of an alkylthiophene oligomer and a pyrrole derivative: copolymer of 3,3′″ dihexyl-2,2′:5′,2″:5″,2′″-quaterthiophene with (R)-(-)-3-(1-pyrrolyl)propyl-N-(3,5-dinitrobenzoyl)-α-phenylglycinate

“…A major focus in the study of electrochromic polymer materials has been that of controlling their colours by main-chain and pendant group structural modification as well as copolymerisation [3,4]. However, the structural modification of these conjugated polymers with the aim to improve their properties is still a challenge.…”