Emergent carbonized polymer dots as versatile featured nanomaterial for latent fingerprints, colorimetric sensor, and photocatalysis applications

Abstract

A facile and multifeatured nanomaterial ‘carbon dots-incorporated polyethyleneimine polymer dots’ (CPPDs) was developed for the utilization in forensic and environmental applications. The one-step hydrothermal method was applied to synthesize CPPDs in which nile blue-derived carbon dots (C-dots) were encapsulated by polyethyleneimine polymeric chains to form a core-shell-nanostructured CPPDs. By taking advantage of the excellent optical spectral properties of CPPDs, three distinct applications including latent fingerprints (LFPs), colorimetric sensors, and metal-free photocatalysis were implemented. CPPDs were employed as a fluorescent probe in the development of LFPs on various substrates. The developed LFPs showed distinct fluorescent patterns with high resolution, providing three levels of identification of a fingerprint including its core, pores, island, and bifurcations. Second, CPPDs were established as a colorimetric sensing probe for the detection of copper ions (Cu2+). When Cu2+ ions were added, the colorless CPPDs solution was turned to a blue color with a detection limit of 6.87 nM. The high selectivity and sensitivity were achieved due to the existence of abundant amine functional groups that led to a stronger interaction with copper ions resulting in complex formation. In addition to LFPs and sensor applications, CPPDs showed their proficiency as a photocatalyst for the degradation of toxic chromium [Cr(VI)] solution. The photocatalytic degradation of Cr(VI) was performed under visible light illumination in which nearly 94% degradation was achieved in 30 min with a rate constant of 0.1339 min−1. An effective degradation process was governed by photogenerated electrons via a reduction reaction. It is anticipated that this work will lead to the development of facile, low-cost, and effective C-dots/polymer dots-based nanomaterials for synergic applications.