Structure and Photocapacitance characteristics of nanosized coumarin-based dye for organic light-dependent resistor applications

Abstract

Abstract The performance of a coumarin-based dye as an organic photoresistor, MACROLEX Fluorescent Red G, as an organic photoresistor was investigated. This commercial dye is highly photostable and efficiently fluorescent for solar energy applications. Specifically, this dye possesses several features, including low price, simple processing, and a high fluorescence quantum yield (90%). A comprehensive characterization was conducted using a range of techniques, such as thermogravimetric analysis (TGA), transmission electron microscopy (TEM), optical absorption, and fluorescence spectroscopy. XRD analysis revealed that the material has a polycrystalline triclinic nanostructure, The calculation of the optical band gap indicated a direct interband transition at 2.1 eV, falling within the range of semiconductor materials. Electrical conductivity and photocapacitance measurements were performed using impedance spectroscopy in the frequency range (20Hz-3MHz) at different temperatures (303–473 K). The dye-based device exhibited a significant enhancement in conductance at an illumination intensity of 100 mW cm−2, surpassing its initial value by more than 27 times. This result supports the potential application of this device as an organic light-dependent resistor (OLDR).