Application Cases

Experiment Name: Optical Modulation Experiment of Electrochromic Dimming Devices

Research Direction: Electrochromic Dimming Display

Experiment Content: By constructing a multi-layer structure of electrochromic devices, an external power supply is achieved through a signal generator connected to a power amplifier, enabling reversible regulation of the optical properties of the electrochromic device in the visible light spectrum, thereby achieving a colorful display effect.

Testing Equipment: ATA-2031 high-voltage amplifier, signal generator, UV-Vis spectrophotometer, computer, etc.

Experiment Process: The experiment centers on a multi-layer sandwich structure of electrochromic devices, using ITO glass as the substrate. A 200nm tungsten oxide (WO₃) layer is deposited as the electrochromic layer via magnetron sputtering, and a 150nm thick PEDOT:PSS counter electrode layer is coated by spin coating. A LiClO₄-PC gel electrolyte is filled in between as the ionic conductor. The interlayer interfaces are enhanced by oxygen plasma treatment and then cured in a vacuum at 80°C for 30 minutes to eliminate bubbles and improve structural density. To achieve dynamic optical modulation of the device, an external power supply system is set up: a square wave signal (0.1Hz, ±1.5V) generated by the Keysight 33500B signal generator is amplified by the AETechron 7224 power amplifier and connected to the device electrodes. The depth of lithium ion insertion into the WO₃ lattice is precisely controlled by adjusting the duty cycle of the square wave (30%-70%).

Optical performance testing is simultaneously conducted using the OceanOptics Maya2000Pro spectrometer to monitor the transmittance changes in the visible light range (400-800nm) and validate the multi-color switching effect through color coordinate calculations. The experiment shows that when a +1.5V positive voltage is applied, lithium ions are extracted, and WO₃ exhibits a highly transparent state with a transmittance of >70%. When a gradient negative voltage (-0.5 to -1.5V) is applied, different amounts of Li⁺ insertion cause the material to display colors such as blue (470nm), gray-green (580nm), and dark gray (650nm). In the cycling stability test, the device shows a transmittance decay rate of <10% after 500 charge-discharge cycles, with a response time consistently below 6 seconds. Further optimization of layer thickness and interface design using COMSOL simulation confirms that a nano-porous structure can shorten the ion diffusion path, achieving a color contrast of over 68%, thus verifying the feasibility of voltage-driven multi-color display.

Figure: Experimental Setup for Optical Modulation of Electrochromic Dimming Devices

Experimental Results: Through the synergistic design of the metal W reflection layer and the dielectric WO₃ resonant cavity, this work successfully achieved dynamic color modulation across the entire visible light range (460-725nm) for inorganic electrochromic devices (ECDs), breaking through the limitation of traditional inorganic materials that can only display a single blue tone. By precisely controlling the thickness of the WO₃ film and the driving voltage, the spectral peak shift can reach up to 181nm, covering high-saturation colors such as yellow, cyan, purple, and magenta (Figure 3h). The device features low driving voltage (-1.5 to 0.5V), high coloring efficiency (75.3 cm²·C⁻¹), and long cycling stability (>1000 cycles). Particularly, its bending stability was verified on a flexible substrate (PET) (Figure 5c), providing an aesthetically and functionally integrated solution for applications such as smart windows and flexible displays.

Figure: Experimental Results

Power Amplifier Recommendation: ATA-2031 High-Voltage Amplifier

Figure: Specification Parameters of the ATA-2031 High-Voltage Amplifier