Single entity detection of organic semiconducting nanoparticles with photoinduced charge quantification

This study is aimed to evaluate the charge accumulation in poly(3-hexylthiophene) nanoparticles (P3HT-NPs) suspended in a physiological solution as consequence of illumination. A series of preparatory experiments were conducted to gather valuable information about precision of the experimental procedure and about the nanoparticles. First, a noise quantification experiment was performed employing shot noise theory to evaluate the system's accuracy. Then, noise characterization was carried out on an electrode/electrolyte system to model the noise magnitude for subsequent experiments involving nanoparticles. Electrochemical impedance spectroscopy (EIS) was employed to gather crucial information such as impedance, admittance, capacitance, and radius of Au-microelectrodes. Next, it was performed an experiment aimed to detect silver nanoparticles in a KCl solution and measure their charge, serving as a preparatory experiment for the chronoamperometric recording and the analysis of single entity electrochemistry experiments. Finally, it was developed a novel experiment for the amperometric detection of photoinduced charge stored in poly(3-hexylthiophene-2,5-diyl) (P3HT) organic nanoparticles. Controlled-size P3HT nanoparticles were prepared using the flash nanoprecipitation method, and their optoelectronic properties were thoroughly analyzed..