context: To quantitatively evaluate the ECD performance, the difference (ΔT) in transmittance values in coloured (TC) and bleached (TB) states is defined as below: The measurement results regarding the visible light transmittance of the ECDs under coloured and bleached states according to various UV curing times of 0, 5, 10, and 20 minutes are presented in Fig. 3a and Fig. S4 (ESI†). To assess the ΔT value, the transmittance values at a wavelength of 550 nm were chosen (Fig. 3b). For the ECD with 5 min of curing, the ΔT was reduced from 54.7% to 51.7%, as shown in Fig. 3b and Table 1. As the UV curing time was delayed, the ΔT values were slightly decreased to approximately 50.0% primarily owing to the increased TC value. This suggests that the UV curing process can deteriorate the EC performance of ECDs. It could be inferred that immobile PMMA molecules block many of the reaction sites on the surfaces of both the electrodes. Fig. 3c shows the dynamic spectra of the UV-cured EDCs at a wavelength of 550 nm under a periodic bias voltage between −1.2 and 0 V. The reliabilities of all the UV-cured ECDs were maintained for the first five cycles, which is comparable to that of uncured ECD using the liquid electrolyte. Furthermore, their low driving voltage of −1.2 V and natural state (0 V) bleaching characteristics are beneficial for low-power devices such as Internet of Things (IoT) devices and wearable displays.