Neutral and

New generation of electrochromic gels: switching from colorless to neutral and multi-color

CIDETEC has developed innovative “all-in-one” electrochromic gels, which allow to fabricate electrochromic devices providing colorless-to-neutral color (i.e. gray or black) and colorless-to-multicolor switching. The unique combination of the “all-in-one” simplified architecture (i.e. electrochromic gel sandwiched between two electrodes) and extension of the electrochromic color palette may open wide avenues for applications such as smart windows, climate adaptive building shells, displays and light filters. (patent application PCT/ES2016/070932).


Besides overcoming the drawbacks of liquid and solid electrolytes, “all-in-one” electrochromic gels result in a stabilization of the chemical species involved in the redox processes behind the electrochromism, leading to improved cyclability and open wide possibilities to extend the electrochromic color palette.

Neutral color

CIDETEC’s electrochromic gels including asymmetric viologens

1. Alesanco et al. ACS Appl. Mater. Interfaces 2016, 8, (43), 29619

2. Alesanco et al. Adv. Optical Mater. 2017, 5, (8), 1600989

Multi-color electrochromism

Single viologen-based CIDETEC’s electrochromic gel:


Two-viologen blend-based CIDETEC’s electrochromic gels:



The new generation “all-in-one” electrochromic gels together with the large CIDETEC’s capacities on electrochromics, open wide possibilities for this technology in well-defined applications such as smart windows and displays, but also in emerging ones such as paper-based electronics. CIDETEC is leading the H2020 INNPAPER project ( funded by the European Commission.