Colorless-to-colorful switching electrochromic polyimides with very high contrast ratio

Abstract

Colorless-to-colorful switching electrochromic polymers with very high contrast ratio are unattainable and attractive for the applications of smart wearable electronics. Here we report a facile strategy in developing colorless-to-colorful switching electrochromic polyimides by incorporating with alicyclic nonlinear, twisted structures and adjusted conjugated electrochromophores, which minimize the charge transfer complex formation. It is noted that, by controlling the conjugation length of electrochromophore, the colorless-to-black switching electrochromic polymer film (PI-1a) exhibites an ultrahigh integrated contrast ratio up to 91.4% from 380 to 780 nm, especially up to 96.8% at 798 nm. In addition, PI-1a film with asymmetric structure also demonstrates fast electrochemical and electrochromic behaviors (a switching and bleaching time of 1.3 s and 1.1 s, respectively) due to the loose chain stacking, which provides more pathways for the penetration of counterion. Moreover, the colorless-to-black EC device based on PI-1a reveals an overall integrated contrast ratio up to 80%.

Flexible and High-Performance Electrochromic Devices Enabled by Self-Assembled 2D TiO2/MXene Heterostructures

“…The absorption coefficient change Δα can be obtained by Δα = αcαb ≈ [ln(Tc/Tb)]/L, which is a physical parameter independent of geometries of the film, thus can be used to compare different technologies. Δα of the LLIA TiO2 film is extracted to be 0.12 nm -1 , which is almost one order of magnitude higher than the previously reported TiO2-based EC materials assembled by other methods (Table S4) (20,(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54), suggesting a very high utilization of TiO2 in the LLIA films during the EC process.…”

Multifunctional electrochromic energy storage devices by chemical cross-linking: impact of a WO3·H2O nanoparticle-embedded chitosan thin film on amorphous WO3 films

“…The use of electrochromic (EC) devices in the production of smart windows is imperative as a primary technology because they can facilitate energy savings by actively adjusting the sunlight flux that enters a building. The ability to regulate heat flow into a building by changing the transparency or reflectance of an EC structure via an applied voltage results in a savings of >40% of the energy consumption 4,5 . In addition, EC devices are promising for use in a variety of optoelectronic applications, such as electronic displays, electronic paper, and rear-view mirrors, due to the realization of multiple colors by the adjustment of the operating voltage 6 .…”

Preparation and Characterization of Semi-Alicyclic Polyimides Containing Trifluoromethyl Groups for Optoelectronic Application

“…There is an urgent need for high-performance polymers available for the advanced manufacturing. Polyimides (PI) are a class of engineering plastics widely applied in electronics, microelectronics, aerospace and energy fields, due to their outstanding thermal, mechanical, chemical resistance and electrical properties [ 4 , 5 , 6 , 7 , 8 ]. Thus, PIs are regarded as the best choice for substrate materials used for flexible optoelectronic applications such as organic electroluminescent displays, flexible thin film solar cells, flexible printed circuits boards with multilayers, etc [ 9 , 10 , 11 , 12 ].…”