Abstract This study reports the first new approach of using nitrogen functionalized carbon dots coated on zinc oxide nanoparticles (N-CDs/ZnONPs) as a novel nanocomposite for latent fingerprint detection using the powder brushing method. N-CDs/ZnONPs nanocomposite was prepared using melamine, potato peel waste and zinc acetate dehydrate as precursors. This nanocomposite was characterized by Fourier-transform infrared spectroscopy, UV–Visible spectroscopy, Fluorescence spectroscopy, X-ray diffraction, Raman spectroscopy, Zeta nanosizer, Scanning Electron Microscope, Energy-Dispersive X-ray Spectrometry and Transmission Electron Microscopy. The size of N-CDs was around at 50–20 nm and ZnONPs was around at 40–50 nm. The quantum yield of N-CDs increased the fluorescence intensity of the fluorophore by 5.54%. The N-CDs were coated on surface of ZnONPs to increase the quantum yield and increase the blue emission after formation of N-CDs/ZnONPs by 5.12%. The N-CDs/ZnONPs nanocomposite demonstrated extraordinary sensitivity and selectivity for Latent Fingerprint (LPF) detection on the distinctive non-porous substrates which included aluminum foil, aluminum sheets, an aluminum rod, an iron disc, a compact disc, a black mat, white marble and magazine paper. This nanocomposite acts as a labeling agent and it helped to detect LFP with clear readability ridges and high contrast fingerprint images under UV light irradiation. N-CDs/ZnONPs nanocomposite additionally demonstrated superior ability to reveal readability ridges and clarity and high contrast LFP images with 415 nm and 450 nm light sources and a yellow filter by using a Living Image Microscope. This nanocomposite exhibited advantages such as improved efficiency, a non-toxic nature, good optical properties and good results in the LFP detection of the freshly applied fingerprints. N-CDs/ZnONPs nanocomposite is, therefore, a good alternative material for detection of latent fingerprints in crime investigations.

中文翻译：

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用于潜在指纹检测的荧光 N-CDs/ZnONPs 纳米复合材料的合成与表征

摘要 本研究报告了第一种使用涂覆在氧化锌纳米粒子 (N-CDs/ZnONPs) 上的氮功能化碳点作为一种新型纳米复合材料，用于使用粉末刷涂法检测潜在指纹的新方法。以三聚氰胺、马铃薯皮废料和脱水醋酸锌为前驱体，制备了 N-CDs/ZnONPs 纳米复合材料。该纳米复合材料通过傅里叶变换红外光谱、紫外-可见光谱、荧光光谱、X 射线衍射、拉曼光谱、Zeta 纳米粒度仪、扫描电子显微镜、能量色散 X 射线光谱和透射电子显微镜进行表征。N-CDs 的尺寸约为 50-20 nm，ZnONPs 的尺寸约为 40-50 nm。N-CDs 的量子产率使荧光团的荧光强度增加了 5.54%。将 N-CDs 涂覆在 ZnONPs 的表面以提高量子产率并将 N-CDs/ZnONPs 形成后的蓝色发射增加 5.12%。N-CDs/ZnONPs 纳米复合材料在独特的无孔基材上显示出对潜在指纹 (LPF) 检测的非凡灵敏度和选择性，这些基材包括铝箔、铝片、铝棒、铁盘、光盘、黑垫、白色大理石和杂志纸。这种纳米复合材料充当标记剂，有助于在紫外线照射下检测具有清晰可读脊和高对比度指纹图像的 LFP。N-CDs/ZnONPs 纳米复合材料还展示了使用活体图像显微镜显示具有 415 nm 和 450 nm 光源和黄色滤光片的可读性脊和清晰度以及高对比度 LFP 图像的卓越能力。这种纳米复合材料具有提高效率、无毒性质、良好的光学特性以及在新应用指纹的 LFP 检测中的良好结果等优点。因此，N-CDs/ZnONPs 纳米复合材料是一种很好的替代材料，可用于在犯罪调查中检测潜在指纹。