聚苯胺电致变色薄膜的红外发射特性研究

Infrared Emission Characteristics of Electrochromic Thin Films Based on Polyaniline

为实现聚苯胺电致变色薄膜红外发射率的大幅度调制,在柔性PET-ITO薄膜基底上恒电位沉积硫酸-磺基水杨酸共掺杂的聚苯胺薄膜.采用扫描电镜和傅立叶红外光谱仪表征了薄膜的形貌和结构,用红外比辐射率测试仪和紫外-可见分光光度计测量薄膜的红外发射率和可见光透过率.在优化电解液浓度配比的基础上,通过建立薄膜红外发射率与方块电阻之间的关系曲线(R-E曲线),深入探讨了影响聚苯胺红外发射特性的关键因素.研究结果表明,在薄膜中聚苯胺厚度和电导率的影响下,红外发射率和方块电阻之间遵循对数函数的变化特征.随着中间态发射率E0的增加,氧化态和还原态的红外发射率呈阶梯状上升,红外发射率调制幅度ΔE先增大后减小,在0.71处达到最大值.同时,红外发射率调节对薄膜的可见光电致变色性能无消极影响,可见光平均透过率之差可达43.8%.

To apply polyaniline thin films in electrochromic devices and optimize their performance,sulfuric acid（ H2SO4 ） and sulfosalicylic acid（SSA） co-doped electrochromic films based on polyaniline were prepared by potentiostatic method on flexible PET-ITO films. The physical properties of the films were studied by scanning electron microscopy（SEM）, infrared emissivity tester, FTIR spectroscopy, four-probe meter and UV- Vis spectrophotometer. The influences of electrolyte concentration ratio and temperature on the performance of PANI films were particularly discussed. To study the infrared emission characteristics of polyanline thin films and find key factors for emissivity changing in deposition process, resistance-emissivity curves （R-E curves） were given and their relationship with emissivity variability was discussed. Based on emissivity variance, electrochromic performance in visible lights were observed. R-E curves confirmed that the relationship between infrared emissivity and resistance follows logarithmic function depending on the effective thickness of the films and the conducting structure of the polymer,which can strongly affect the emissivity variability of polyaniline thin films. With the increase of original emissivity （E0） , the variability AE first increased, and reached the highest value when E0 was 0.71. After that △E reduced. The results of UV-Vis spectra confirmed that the films could realize good emissivity variability and at the same time get high contrast of visible lights （△T%） between coloring and bleaching. When E0is 0.71 ,the △T% at average of visible light wavelength is 43.8%.