Department of Chemistry, Umm Al-Qura University, Makkah, Saudi Arabia.
Department of Chemistry, College of Science, University of Tabuk, Tabuk, Saudi Arabia.
Microsc Res Tech. 2022 Dec;85(12):3871-3881. doi: 10.1002/jemt.24244. Epub 2022 Oct 14.
Simple and efficient detection and mapping method based on a strong turn-on fluorescent pigment was developed for fingerprint analysis. We present a phosphor powder characterized by strong emission which is useful to achieve better fingerprint detection on multicolored or photoluminescent surfaces, such as currency notes characterized by optically changeable inks and highly fluorescent positions, because it offers better contrast and reduce the difficulty of background interference. Novel photochromic ink was prepared to establish a fingerprinted colorless film onto cellulose documents with green emission for anticounterfeiting applications as illustrated by photoluminescence spectra. Inorganic/organic nanoscale composite ink was prepared from rare-earth doped aluminate phosphor nanoparticles (PNPs; 27-49 nm) dispersed in a polyacrylic acid binding agent. PNPs were dispersed efficiently in polyacrylic acid to generate a colorless mark. The produced photochromic inks were spray-coated onto off-white paper sheets enclosing invisible fingermarks, and then exposed to thermofixation. Photochromic film was detected on paper surface presenting a transparent appearance under visible daylight and switchable to green under UV light. The CIE Lab parameters and photoluminescence spectra were studied under visible light and ultraviolet irradiation. The fingerprinted sheets showed fluorescence band at 517 nm upon excitation at 366 nm, showing a bathochromic shift and reversible photochromism without fatigue. The morphologies of pigment phosphor particles and fingerprinted sheets were inspected. The rheological properties of ink and mechanical behavior of the fingerprinted paper samples were explored. HIGHLIGHTS: Novel smart ink with alkaline-earth aluminate and polyacrylic acid was developed. Dual-mode fluorescent photochromism was presented for latent fingerprint analysis. Off-white fingerprinted films under daylight showed color change to green under UV. Fluorescence band monitored at 517 nm upon excitation at 366 nm. Fluorescent fingermark on paper sheets demonstrated good photostability.
基于强开启荧光颜料的简单高效检测和测绘方法被开发出来，用于指纹分析。我们提出了一种具有强发射特性的荧光粉，可用于在多色或磷光表面上实现更好的指纹检测，例如具有光学变色油墨和高荧光位置的钞票，因为它提供了更好的对比度并降低了背景干扰的难度。我们制备了新型光致变色油墨，在纤维素文件上建立无色指纹膜，发出绿色发射光，用于防伪应用，如磷光光谱所示。将掺稀土的铝酸盐荧光粉纳米粒子 (PNP；27-49nm) 分散在聚丙烯酸结合剂中，制备出无机/有机纳米复合油墨。PNP 有效地分散在聚丙烯酸中，生成无色标记。将制备的光致变色油墨喷涂在包含不可见指纹的白色纸张上，然后进行热固定。在可见日光下，光致变色膜在纸张表面呈现透明外观，在紫外光下可切换为绿色。在可见光和紫外线照射下研究了 CIE Lab 参数和磷光光谱。在 366nm 激发下，指纹片在 517nm 处显示出荧光带，表现出红移和可逆光致变色，无疲劳现象。检查了颜料荧光粉颗粒和指纹片的形态。研究了油墨的流变性能和指纹纸样品的机械性能。要点：开发了新型含堿土铝酸盐和聚丙烯酸的智能油墨。呈现双模式荧光光致变色，用于潜伏指纹分析。在日光下呈白色的指纹膜在紫外线下显示为绿色。在 366nm 激发下，在 517nm 处监测到荧光带。在纸张上的荧光指纹显示出良好的光稳定性。
