Journal of Inorganic Materials, Volume. 39, Issue 4, 432(2024)
In recent years, humidity sensors have attracted widespread attention from researchers in fields such as food safety and soil monitoring. Traditional humidity sensors exhibit the advantages of good stability and high sensitivity. However, most humidity sensing systems convert humidity signals into recognizable waveforms through wired connections and large external devices, making it impossible to achieve real-time visual monitoring of changes in humidity information. Currently, direct conversion of humidity information into visible color signals by eyes provides an ideal solution to the aforementioned problems but still lacks intelligent monitor capacity. This study integrated humidity sensors and electrochromic devices (ECDs) to prepare an intelligent visual humidity monitoring system. By converting humidity signals into voltage signals to drive ECDs, stable and reversible color change in the system could be achieved. The ECDs were prepared using tungsten trioxide (WO3) as the negative electrode and zinc foil (Zn) as the positive electrode. Based on the output voltage of the humidity sensor, it achieves transitions between different working states, thereby generating color signals that can be observed by the naked eyes. Electrochemical performance and electrochromic performance of ECDs were tested and characterized by using a UV-visible spectrophotometer and an electrochemical workstation. Subsequently, the performance of the conditioning circuit was analyzed using an oscilloscope and a humidity generation platform. The results show that the intelligent electrochromic humidity indicator has good stability and rapid response performance, where the coloring time and fading time are only 7.5 s and 4.5 s, respectively. After 300 cycles, the optical modulation (ΔT) is basically maintained the same as the initial value, and the retention rate can reach more than 95%. Therefore, this visual humidity indication system which possesses novel design and simple structure has promising broad application in fields such as artificial intelligence and intelligent agriculture.
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Mingshuo ZHEN, Xiaoran LIU, Xiangqian FAN, Wenping ZHANG, Dongdong YAN, Lei LIU, Chen LI.
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Received: Sep. 26, 2023
Accepted: --
Published Online: Jul. 8, 2024
The Author Email: LI Chen (lichen@nuc.edu.cn)