Novel moisture‐sensitive binary films that exhibit reversible change in fluorescent color have been created using a fluorescent amorphous molecular material, 4‐[bis(4‐methylphenyl)amino]benzylideneaniline (BMBZA), with organic acids such as pentafluorobenzoic acid and benzoic acid. Orange fluorescent color of the film under ambient dry atmosphere was found to change drastically to greenish blue under wet atmosphere. Response speed of such color change was quite fast and it responded well to exhaled breath. It was suggested that such change in fluorescent color was due to switching the excited species between BMBZA and its protonated iminium cation, and that the acidity level of the organic acids was an important factor for exhibiting such reversible changes in fluorescent colors. In addition, excited‐state intermolecular proton transfer was suggested to contribute the orange fluorescence under dry atmosphere.

中文翻译：

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4- [双（4-甲基苯基）氨基]亚苄基苯胺与有机酸的湿敏二元膜的荧光色的可逆变化

使用荧光无定形分子材料4- [双（4-（甲基苯基）氨基]苄叉基苯胺（BMBZA）和五氟苯甲酸和苯甲酸等有机酸制成了新颖的湿敏二元薄膜，该薄膜具有可逆的荧光颜色变化。发现在环境干燥气氛下膜的橙色荧光色在潮湿气氛下急剧变化为绿蓝色。这种颜色变化的响应速度非常快，并且对呼出气的响应也很好。有人认为，这种荧光颜色的变化是由于在BMBZA和其质子化的亚胺阳离子之间切换了激发物种，而有机酸的酸度水平是显示这种荧光颜色可逆变化的重要因素。此外，