A New High-Performance Blue to Transmissive Electrochromic Material and Use of Silver Nanowire Network Electrodes as Substrates

Synthesis of a novel, high-performance blue to transmissive switching electrochromic material is described. The polymer (P1) was prepared by both electrochemical (P1E) and chemical (P1C) means from the corresponding monomer. The electrochemically synthesized polymer (P1E) revealed 64% optical contrast change (on ITO) in the visible region and very fast switching times of 0.32 s (coloration) and 0.90 s (bleaching). On the other hand, the chemically synthesized, solution processable polymer (P1C) also showed a high optical contrast value (49%, on ITO) with very fast switching times of 0.86 s for coloration and 0.57 s for bleaching. These high optical contrast values coupled with fast switching times place these materials along with high-performance blue to transmissive electrochromic polymers. Significantly, these improved characteristics were achieved by side chain engineering of a known, inferior blue to transmissive polymer, PBEBT. Towards fabrication of flexible electrochromic devices, the performance of P1C was also tested on silver nanowire network electrodes. Even though the full potential of the material could not be demonstrated, a good optical contrast of 24% was achieved using these electrodes. Under the same potential range allowed by silver nanowire network electrodes, P1C on ITO showed an optical contrast of 30%. (C) 2017 Wiley Periodicals, Inc