磷光碳点粉末的合成及其在抗背景干扰的潜指纹成像中的应用

Phosphorescent carbon dots powder:Synthesis and application in anti‑background interference latent fingerprint imaging

以乙二胺、磷酸和硼酸为反应物,采用水热法制备了荧光碳点(CDs)溶液,进一步加热水热反应溶液,获得了磷光CDs粉末。利用X射线衍射(XRD)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、紫外可见(UV-Vis)吸收光谱和光致发光光谱等对CDs的结构、形貌和尺寸、表面基团与化学组成以及光学特性进行了表征。结果表明,合成的CDs粉末为无定型碳,形貌为单分散的近球形,尺寸分布在3.78~7.64 nm范围之内,其表面存在大量的N、P和B杂原子基团。CDs粉末在365 nm紫外光照射下呈现明亮的蓝色荧光,关闭激发光后,呈现长达10 s的绿色室温磷光。该CDs粉末可作为指纹试剂应用于具有复杂背景图案且有强荧光发射基质表面的潜指纹(LFPs)显现。显现后的LFPs在激发光关闭后均呈现明亮完整的磷光指纹图谱,指纹细节特征清晰可辨,有效消除了背景图案与背景荧光干扰。同时,制备的CDs粉末对不同干扰背景客体表面老化7 d的LFPs也能够显现出清晰可识别的磷光指纹图谱。

In this work,fluorescent carbon dots(CDs)solution was prepared via a hydrothermal method with ethyl-enediamine,phosphoric acid,and boric acid as starting materials.Subsequently,the obtained solution was heated at 180℃ for 5 h to get phosphorescent CDs powder.The structure,morphology and size,surface groups and chemical compositions,and optical properties of as-prepared CDs were then characterized by powder X-ray diffraction(XRD),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),ultraviolet-visible absorption spectroscopy,and photoluminescence spectra.The results showed the synthesized CDs were amorphous carbon structure,well-dispersed,and sphere-like in shape with a diameter of 3.78-7.64 nm.CDs were rich in heteroatom groups containing N,P,and B on the surface.Under 365 nm UV light irradiation,the CDs powder exhibited bright blue fluorescence,and green room-temperature phosphorescence(RTP)was observed for up to 10 s after switching off the 365 nm light irradiation.The as-obtained CDs powder as an efficient fingerprint reagent was successfully used for developing latent fingerprints(LFPs)on substrates with complex background patterns and strong back-ground fluorescence.After turning off the 365 nm UV light,the clear whole fingerprint shapes with well-defined details can be observed.The background patterns and background fluorescence interference were efficiently elimi-nated by capturing the phosphorescent latent fingerprint images.Meanwhile,the developed 7-day-old LFPs on various substrates with strong background interference showed well-resolved green ridge flow phosphorescence finger-print patterns.