摘要
电解质层位于电致变色器件的中心,通过电解质离子在电极材料中的嵌入和脱出,调控电极的可逆氧化还原反应,从而实现器件颜色变化。传统Li^(+)电解质的响应速度较慢,无法满足快速响应的需求。基于在Li^(+)电解质中掺入Al^(3+)可以显著提升电致变色性能,制备了5种不同离子数比例的Li^(+)/Al^(3+)复合电解质,研究其对WO_(3)薄膜电致变色性能的影响。结果表明,Li^(+)/Al^(3+)复合电解质与纯Al^(3+)电解质的着色响应时间和记忆效应明显优于纯Li^(+)电解质。当c(Li^(+))∶c(Al^(3+))=1∶3时,着色响应时间最短,为1.05 s;开路28 h后,550 nm波长处的透过率仅增加7.1%。同时,复合电解质条件下的WO_(3)薄膜在循环稳定性方面显著优于纯电解质,尤其当c(Li^(+))∶c(Al^(3+))=1∶3时,表现出优异的循环性能。在1000圈循环伏安(CV)测试后,电荷容量保持率高达90.38%。本工作系统探讨了Li^(+)/Al^(3+)离子比例对WO_(3)薄膜电致变色性能的影响,对WO_(3)基电致变色器件的优化和应用具有重要的指导意义。
Objective Traditional Li^(+)electrolytes often fail to meet the requirements for fast response due to their slower response speed.In this paper,we prepare five Li^(+)/Al^(3+)composite electrolytes with varying Li^(+)/Al^(3+)ratios to investigate their effects on the electrochromic properties of WO_(3) thin films fabricated via magnetron sputtering.The results demonstrate that the coloring response time and memory effect of WO^(+3+)_(3) films in Li/Al^(3+)composite and pure Al electrolytes significantly outperform those in pure Li^(+)electrolytes.Specifically,when the Li^(+)/Al^(3+)ratio is 1∶3,the coloring response time is minimized at 1.05 s,and after 28 h under open-circuit conditions,the transmittance at 550 nm increases by only7.1 percentage points.Moreover,the cycle stability of WO_(3) films in composite electrolytes is markedly superior to that in pure electrolytes.Particularly at a Li^(+)/Al^(3+)ratio of 1∶3,the WO_(3) film exhibits optimal cyclic performance,with a charge retention rate of 90.38% after 1000 cycles of voltammetric cycling (CV) testing.Methods WO_(3) films are deposited on indium tin oxide (ITO) substrates via DC reactive magnetron sputtering.Film thickness is measured using a BrukerDektakXT step profiler,and scanning electron microscopy (SEM) imaging is conducted with a Zeiss Sigma 500 at 15 kV.X-ray diffraction (XRD) analysis is performed using Philips X’Pert diffractometer with Cu Kα radiation to determine the crystalline structure of the films.Electrochemical properties are measured in a standard three-electrode setup using an Ag/AgCl reference electrode in various lithium perchlorate/aluminum perchlorate LiClO_4/Al(ClO_4)_(3) electrolytes dissolved in propylene carbonate (PC).Chronoamperometry and cyclic voltammetry tests using a CHI760E electrochemical workstation are employed to evaluate response times and cyclic performance.Ultraviolet-visible (UV-Vis) spectrophotometry (Shimadzu UV-3600 plus) is used to characterize modulation rates.Results and Discussions Five groups of Li^(+)/Al^(3+)composite electrolytes with different ratios are prepared,and their effects on the electrochromic performance of WO_(3) film are studied.Key findings include:1) The light modulation rate of WO_(3) films in Li^(+)/Al^(3+)composite electrolyte is higher than in pure Li^(+)electrolyte (Fig.2).2) Adding Al^(3+)to Li^(+)electrolytes significantly reduces the coloring response time,though the fading time gradually increases with higher Al^(3+)content (Fig.3).3) After 28 h under open-circuit conditions,the transmittance increase of WO_(3) films in composite electrolytes (4 percentage points-9 percentage points) is similar to that in pure Al^(3+)electrolyte (8.4 percentage points) but significantly smaller than in pure Li^(+)electrolyte (Fig.4).4) With increasing Al^(3+)content,the Q_(ex)/Q_(in) ratio increases,achieving the highest stripping efficiency at a Li^(+)/Al^(3+)ratio of 1∶3 (Fig.5).Conclusions In this paper,we prepare WO_(3) thin film via DC reactive magnetron sputtering,and the effects of different Li^(+)/Al^(3+)ratios on their electrochromic properties are thoroughly investigated.XRD and SEM analysis reveal that WO_(3thin) films are amorphous with a uniform,porous,and loose structure.Notably,incorporating Al^(3+)into Li^(+)composite electrolytes significantly reduces the coloring response time of WO_(3) thin films,compared to pure Li^(+)electrolytes.Among the tested ratios,a Li^(+)/Al^(3+)ratio of 3∶1 yields the best memory effect with the transmittance of the WO_(3) thin film increasing by only 4.8 percentage points after 28 h under open-circuit conditions.Moreover,the WO_(3) thin film demonstrates the shortest coloring response time (1.05 s) and superior cycle stability when the Li^(+)/Al^(3+)ratio is 3∶1.At this ratio,the charge density reaches 21.08 mC/cm^(2),and the charge retention rate remains as high as 90.38%.These findings confirm that introducing Al^(3+)into Li^(+)electrolytes enhances the electrochromic properties of WO_(3) thin film.By optimizing the Li^(+)/Al^(3+)ratio in the electrolyte solution,the electrochromic performance of WO_(3) films can be effectively controlled,offering a promising approach for achieving a film with better functionality.
作者
郑浩彬
唐岩
周兴龙
唐秀凤
张炯
袁双双
Zheng Haobin;Tang Yan;Zhou Xinglong;Tang Xiufeng;Zhang Jiong;Yuan Shuangshuang(School of Applied Physics and Materials,Wuyi University,Jiangmen 529020,Guangdong,China;School of Civil Engineering and Architecture,Wuyi University,Jiangmen 529030,Guangdong,China)
出处
《光学学报》
北大核心
2025年第3期273-281,共9页
Acta Optica Sinica
基金
2022年广东省攀登计划项目(pdjh2022a0524,pdjh2022a0522)。
关键词
薄膜
复合电解质
电致变色性能
氧化钨
循环稳定性
thin films
composite electrolyte
electrochromic performance
tungsten oxide
cycle stability
