基于PEDOT:PSS层的自供能电致变色器件的制备及性能

Preparation and properties of self-powered electrochromic devices based on PEDOT:PSS layer

摘要:

为制备结构简化、具有优异性能的自供能电致变色器件（ECDs），基于聚(3,4-乙烯二氧噻吩):聚(苯乙烯磺酸)（PEDOT:PSS）的变色和导电特性，在聚对苯二甲酸乙二醇酯（PET）基材上制备PEDOT:PSS薄膜，将其作为电致变色层和电极层的共用功能层制备自供能ECDs。通过超景深三维数字显微镜和快速傅立叶变换（FFT）表征，考察旋涂转速（500、1000、1500 r/min）对PEDOT:PSS电极表面形貌和均匀性的影响。采用万用表和分光光度计，探究不同金属（Zn、Al、Cu）阳极对自供能ECDs光学性能的影响。采用循环伏安（CV）、恒电流充放电（GCD）和电化学阻抗谱（EIS）测试，表征PEDOT:PSS电极和自供能ECDs的电化学性能。并将紫外-可见-近红外分光光度计与电化学综合测试仪连用，测试自供能ECDs的光学和循环性能。结果表明，旋涂转速1500 r/min制备的PEDOT:PSS电极具有平整和均匀的形貌。Zn为金属阳极的自供能ECDs具有优异的光学和电化学性能，色差为13.36，着褪色时间分别为3.0和4.2 s，着色效率为58.38 cm2/C；在0.01 mA/cm2的电流密度下具有4.89 mA·h/m2的面积比容量，等效串联电阻为181.6 Ω。Zn为金属阳极的自供能ECDs经4000 s后的透射率对比度仍达到80%，处于90°弯曲状态下器件具有平整状态93.5%的比容量保持率。

Abstract:

To fabricate simplified-structure, high-performance self-powered electrochromic devices (ECDs), poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films were prepared on polyethylene terephthalate (PET) substrates, leveraging the color variability and electrical conductivity of PEDOT:PSS, to serve as a common functional layer for both the electrochromic layer and the electrode layer in the self-powered ECDs. The surface morphology and uniformity of PEDOT:PSS electrodes were characterized using a ultra-depth 3D digital microscope and fast-fourier transform (FFT) analysis, with the effect of spin-coating speeds (500, 1000, 1500 r/min) on the electrodes being investigated. The optical performance of self-powered ECDs with different metal (Zn, Al, Cu) anodes was explored using a multimeter and a spectrophotometer. The electrochemical performance of PEDOT:PSS electrodes and self-powered ECDs was characterized through cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) tests. An ultraviolet-visible-near-infrared spectrophotometer was connected to an electrochemical workstation to test the optical and cycling performance of the self-powered ECDs. Results indicated that PEDOT:PSS electrodes prepared at a spin-coating speed of 1500 r/min exhibited a smooth surface morphology and excellent uniformity, which facilitated ion diffusion at the electrode-electrolyte interface. Self-powered ECDs with Zn as the metal anode demonstrated superior optical and electrochemical properties, with a color difference of 13.36, coloration and bleaching time of 3.0 and 4.2 s, respectively, a coloration efficiency of 58.38 cm2/C, and an area specific capacity of 4.89 mA·h/m2 at a current density of 0.01 mA/cm2, along with an equivalent series resistance of 181.6 Ω. The devices showed commendable cycling and mechanical stability, maintaining approximately 80% of their initial transmittance contrast ratio after 4000 s of cycling. Moreover, compared to their original flat state, the devices retained 93.5% of their discharge capacity under a 90° bending condition. The fabricated self-powered ECDs hold significant potential for application in flexible display devices.