Estimation of methyl orange dye’s molar absorptivity using a photoresistor-based photometer

Abstract

The need to further develop solar cell technology, particularly on dye-sensitized solar cells (DSSCs), drives absorption studies of various chemical species. In this study, absorbance analysis of methyl orange (MO) dye was performed using the adapted and modified photoresistor-based photometer of Adams-McNichol et al. [1]. The research aims to improve the stability of the reference setup, while maintaining the accuracy of absorbance results it yields. The methodology includes photometer fabrication, MO dye sample preparation, and the evaluation of MO dye’s molar absorptivity in an aqueous solution. Results show that the estimated molar absorptivity of MO using the voltage readings from the photometer is close to the literature value, with a percentage error of 1.44%. This finding demonstrates that the modified photometer retains its effectiveness, as supported by the method repeatability measurements from six samples for each of the following MO concentrations: 0 μM, 40 μM, 45 μM, and 50 μM. Considering these results, the device may be useful in teaching light absorption to students as an alternative to the “black box” approach, and in exploring purified natural dyes that have potential applications in solar cell technology.